Welcome to the beautiful state of Wisconsin where natural wonders abound and the cheese is delicious. Wisconsin offers much more than just these though; it’s also a great location for an Accessory Dwelling Unit (ADU). These compact, modular houses are an addition to your primary dwelling and open the doors for housing elderly parents, Airbnb rentals, and space for family and friends. Plus they are great investment options and increase your property value!
Zook Cabins is excited to present the essential information about ADU regulations and restrictions in Wisconsin, so you have the tools for success. From sizing laws to specific town guidelines, we’ll cover it all. Let’s go!
Are ADUs Allowed in Wisconsin?
Addressing the most critical question isn’t so black and white; it has more complexities than a simple yes or no. Wisconsin lacks a statewide law dictating the exact guidelines for ADUs in all counties and municipalities. Instead, it is left up to the discretion of local governments. This can be good news though! If there aren’t specific laws around ADUs in your town, your local zoning and building departments may be more open to the possibility of an ADU on your property, through use of a conditional permit.
So, in essence, yes, ADUs are allowed in many parts of Wisconsin, but most counties don’t have clear regulations for them yet, prompting homeowners to contact them directly to find out more. As ADUs continue to gain popularity across the nation and Wisconsin, statewide guidelines could pass.
What Is Considered An ADU in Wisconsin?
Wisconsin defines an accessory dwelling unit as a separate living unit on the same lot as a main dwelling unit with independent cooking, eating, and sleeping facilities. It can be multi bedroom, but must remain in the size limit outlined by the municipality.
Can Park Model ADUs Be Used As ADUs?
Our version of a tiny home, known as park model homes, are extremely popular for their compactness and versatility. Because park model homes are built to RV standards they may not qualify as an ADU in Wisconsin. However, this is typically determined by the local zoning board.
Take a look at the table below to see what Wisconsin, and all the other states that we deliver to, have to say about tiny home regulations.
| AL | IL | MN | NC | TX |
| AZ | IN | MS | ND | UT |
| AR | IA | MO | OH | VT |
| CA | KS | MT | OK | VA |
| CO | KY | NE | OR | WA |
| CT | LA | NV | PA | WV |
| DE | ME | NH | RI | WI |
| FL | MD | NJ | SC | WY |
| GA | MA | NM | SD | |
| ID | MI | NY | TN |
Can Log Cabins Be Used As An ADU?
Absolutely! Log cabins are an ideal choice for ADUs if you’re wishing for a timeless, cozy feel. An important thing to remember is the size restrictions. Since many counties and towns cap ADU size at 800-1000 sq feet, not all log cabins will work for your needs. Luckily, Zook Cabins offers several models that start at 700 square feet.
Can Modern Cabins Be Used As An ADU?
Not interested in a rustic feel? A sleek modern cabin might be what you need instead with a trendy interior and a modern exterior. As with log cabins, you’ll need to be mindful of sizing requirements and choose a model that stays within your county’s requirements.
What is the Difference Between a Prefab ADU & a Modular ADU?
The main difference comes down to the crafting and assembly. Prefab ADUs are created almost entirely in a factory or warehouse then transported to the site and installed. In contrast, modular ADUs are built in sections, then those sections are taken and assembled on the site. This allows for final adjustments and corrections.
When it comes to permits and regulations, there isn’t a distinction between prefab and modular ADUs.
What is the Minimum Size for an Accessory Dwelling Unit?
Because there is no statewide law, there is no standard minimum size set either. Typically in Wisconsin, minimum size is between 120-200 square feet, and your zoning department can confirm this for you. However, all of the tiny homes, ADUs, log cabins, and modern cabins are larger than 200 square feet.
Can My ADU be Bigger Than My House?
No. Remember, the purpose of an ADU is to complement your current dwelling and provide additional space, not overwhelm it. Often, the size of an ADU will be capped at around 800-1000 square feet or up to a certain percentage of your house’s square footage. 50-75% is common, but it could be as low as 40%.
How Close To My House Can I Build An ADU?
Setback requirements follow the same as other accessory structures like sheds and garages. This is usually 10 feet rear setback and 5 feet from the sides. As always, we recommend homeowners to reach out to their local building or zoning departments for more guidance.
Do You Need A Permit For An ADU in Wisconsin?
Yes, you will need several permits before building your ADU. The first and most foundational is the building permit which is required for most accessory buildings. With living quarters included in the ADU, you will probably need an electrical, plumbing, and HVAC permit as well. Our recommendation is to start the process in advance and be patient, as these can take some time.
Are There Any Incentives or Grants for ADUs in Wisconsin?
Unfortunately, there are none listed as feasible options for Wisconsin. However, this may change in future years, so be sure to keep your eyes out for any potential grants and funding options. Additionally, you can also check to see if you qualify for another housing grant which could be applied to your ADU.
Are Zook Cabin’s ADUs Built to Code?
Definitely! We take pride in thoroughly inspecting each ADU before it leaves the lot, ensuring that it meets the local building codes where you live. Our team of designers and builders match and exceed the building codes so all you have to do is sit back and relax, knowing we have it covered. Curious to learn more? Contact our team so we can answer your questions!
Can an ADU Have Multiple Bedrooms and Bathrooms?
Yes, many models allow for a multi-bedroom and bathroom set up. While a one-bedroom, one-bath model is the most popular, that might not suit your needs if you want more space. Browse our selection to see which one works best for you.
Are ADUs A Good Investment?
Yes, they definitely are! Not only do they increase your property value, they present opportunities to rent to other people, if regulations allow. Many people report a quick return on investment when they choose an accessory dwelling unit. Of course, it is important to consider all the factors and choose the best model for your situation. Our team is happy to talk you through the process and help you consider your financing options.
What Counties in Wisconsin Allow ADUs?
Does Milwaukee County Allow ADUs?
Yes! Milwaukee County allows ADUs, but the important detail is that most zoning authority sits with the individual cities, not the county itself. In unincorporated areas of Milwaukee County (which are limited), ADUs are generally treated as accessory residential uses and must comply with underlying zoning, lot size, and building code requirements. In practice, most homeowners encounter ADU rules through municipal ordinances rather than county-wide standards. Where allowed, ADUs are typically limited to one unit per lot, must remain subordinate to the primary dwelling, and cannot be sold separately.
If you’re in Milwaukee County, the next step is to confirm whether your property is inside a city boundary or in a rare unincorporated area. County planning staff can confirm jurisdiction, but the city zoning department will usually control ADU size limits, setbacks, and permit review. Always confirm whether detached ADUs are allowed or if the county defers entirely to municipal code.
Does Dane County Allow ADUs?
Yes, Dane County allows ADUs in unincorporated areas and towns that use county zoning, and it is one of the clearer counties in Wisconsin on baseline standards. ADUs are generally capped at 800 square feet with a maximum of two bedrooms, and owner occupancy is required, meaning the owner must live either in the primary home or the ADU. Only one ADU is allowed per lot, and it cannot be sold separately from the main residence. Parking, setbacks, and lot size requirements still apply and are often what determine whether an ADU is feasible on a specific parcel. Reach out to the Zoning Department for the next step in the process.
Does Waukesha County Allow ADUs?
It is unclear as Waukesha County does not have a simple, countywide ADU allowance that applies everywhere. With that said, ADUs may be possible depending on the town and zoning district. In unincorporated areas, accessory dwelling units are typically evaluated under accessory use and residential density standards rather than a modern ADU-specific ordinance. That means ADUs may be allowed in concept, but size limits, setbacks, and approval requirements can vary significantly by zoning classification.
Because Waukesha County has many municipalities that control their own zoning, most homeowners will need to confirm whether county zoning or city zoning applies first. The next step is to contact the county or town zoning office with your parcel information and ask whether a second dwelling unit is allowed on a single-family lot and whether it must be attached to the primary structure. Septic capacity and minimum lot area are frequent limiting factors in this county.
Does Brown County Allow ADUs?
It sure does! Brown County allows ADUs in certain unincorporated areas, but approval is highly zoning-dependent and often more conservative than in large urban counties. ADUs are generally treated as accessory residential uses and must remain clearly smaller than the primary home. Owner occupancy is commonly required, and only one ADU is allowed per parcel.
Detached ADUs may face additional scrutiny in Brown County, especially in rural or agricultural districts where density is tightly regulated.The next step is to identify your zoning district and ask the Brown County Planning and Land Services Department whether ADUs are allowed by right or require a conditional approval.
Does Racine County Allow ADUs?
Unfortunately, Racine County does not publish a single, easy-to-reference ADU standard that applies uniformly across all unincorporated areas, but ADUs may be allowed depending on the zoning district. . Where permitted, ADUs are typically limited to one per lot, must remain accessory to the primary residence, and cannot be sold separately.
In Racine County, the biggest hurdle is usually classification, that is, whether the county considers the proposal an ADU, an accessory living unit, or an expansion of residential density. That classification determines whether the unit is allowed at all. The correct next step is to contact the county zoning office or your town zoning administrator and ask how an ADU is defined in your district. They will help you forward in the process.
Does Outagamie County Allow ADUs?
Yes, Outagamie County allows ADUs, but in this county the “ADU” concept is most clearly spelled out as an accessory apartment inside a single-family home rather than a freestanding backyard cottage. The county’s standard is a practical one and says that the accessory apartment must be capped at 600 square feet or 25% of the home’s total floor area (whichever is greater), and it’s intended for a small household rather than a full second residence. This means detached units like the ones Zook Cabins specializes in are not an option for Outagamie.
Does Winnebago County Allow ADUs?
Yes, but not necessarily at the county level. Winnebago County can allow ADUs, but you shouldn’t assume there’s one countywide rule that applies everywhere. The county zoning department’s own guidance points homeowners to first confirm your property’s zoning then verify what Chapter 23 allows for your district, and if your town hasn’t adopted county zoning, you’ll be dealing with the town’s ordinance instead. In other words, ADU permission is possible, but it’s jurisdiction-driven and district-driven.
Does Kenosha County Allow ADUs?
Yes! Kenosha County allows ADUs, and the rules are unusually specific, just not in the way most people expect. Kenosha frames this as an “Accessory Living Unit” within a single-family setup, and it’s tightly capped at one per single-family dwelling, no more than 600 square feet, and no more than two residents. The county also emphasizes keeping the property reading like a single-family home, which is why it restricts things like making it look and function like a separate house.
Here again, you can not purchase an ADU from Zook Cabins in this county, but internal ADUs are an option for you.
Does Rock County Allow ADUs?
Possibly, but you may have to go to more local government. Rock County may allow ADUs, but the county government itself is not where most homeowners will find a simple “ADU ordinance” that applies everywhere. Rock County’s land-use role is heavily focused on shoreland zoning and floodplain zoning, while cities and towns typically control day-to-day residential zoning standards like ADUs. That means your actual answer depends on whether you’re inside a municipality or in a town that uses its own zoning ordinance. To avoid unnecessary communication, reach directly out to your local zoning department and see what they have to say.
Does Marathon County Allow ADUs?
Just like other Wisconsin counties, Marathon County can allow ADUs, but it’s a “know-your-jurisdiction” county where the county zoning program applies only to towns that participate in Marathon County Zoning, and the county explicitly tells residents to start by identifying the zoning district using the zoning maps before assuming what’s allowed. Your next step is to confirm whether your town is under county zoning, pull the parcel’s zoning district from the maps, and call Marathon County’s zoning staff with your parcel info to ask what form of “second unit” is allowed in that district.
Does Washington County Allow ADUs?
Washington County can allow ADUs, but they are not presented as a simple, one-size-fits-all option at the county level. In unincorporated areas, ADUs are typically evaluated under accessory use and residential density rules tied to the zoning district rather than a modern, standalone ADU ordinance. That means the county looks closely at whether a second dwelling unit maintains the character of a single-family property and complies with setbacks and coverage requirements. Owner occupancy is often expected, and only one ADU per parcel is typically allowed. To confirm this, reach out to your local zoning department.
Does La Crosse County Allow ADUs?
Yes, La Crosse County allows ADUs in unincorporated areas, and its ordinance is more explicit than many rural counties. The county permits one accessory dwelling unit per lot, requires owner occupancy, and limits the ADU so it remains clearly subordinate to the primary residence. Detached ADUs must be located within a defined distance of the main home, reinforcing the idea that the unit is accessory rather than a separate residence. The ADU’s square footage cannot exceed that of the principal dwelling, which effectively caps size without relying on a single square-foot number. Check the zoning department for more guidance on permits and setback standards.
Does Sheboygan County Allow ADUs?
In some places, yes! Sheboygan County allows ADUs in unincorporated areas, but they are regulated carefully to preserve low-density residential patterns. ADUs are generally limited to one per lot and must remain accessory to the primary dwelling, with owner occupancy commonly required. Rather than using a single countywide size cap, Sheboygan County often ties the maximum size of an ADU to the size of the main house which can vary by zoning district.
Detached ADUs are possible in some districts but are closely reviewed for setbacks, access, and compatibility with surrounding uses. The best next step is to identify your zoning district and ask county planning staff whether an ADU is permitted by right or requires a conditional approval, and what other standards apply to your parcel.
Does Eau Claire County Allow ADUs?
Following the pattern of many Wisconsin counties, Eau Claire County does allow ADUs, but approval depends heavily on the zoning district and whether the town participates in county zoning. The county tends to evaluate ADUs through existing residential and accessory use standards rather than a dedicated ADU chapter, which means proposals are reviewed case by case. The next step for homeowners is to determine zoning classification, and contact county zoning staff to clarify whether a second dwelling unit is allowed and what approvals are required.
Does Walworth County Allow ADUs?
Yes, but with strict limitations. Walworth County allows ADUs in certain unincorporated areas, but like many counties in southeastern Wisconsin, the rules are conservative and highly zoning-dependent. ADUs are typically treated as accessory residential uses rather than independent dwellings, with limits on number, size, and occupancy. Owner occupancy is commonly required, and the ADU must remain clearly secondary to the primary home. Detached ADUs may be restricted or require special approval depending on the zoning district.
To find out the specific details for your property, we suggest contacting the local planning department and asking them about your area’s restrictions.
Does Fond du Lac County Allow ADUs?
Fond du Lac County allows ADUs in unincorporated areas, but the county takes a structured, building-code-first approach rather than promoting detached backyard units broadly. ADUs are most commonly approved as internal or attached units within an existing single-family home, and only one ADU is allowed per parcel.
If you’re considering an ADU here, the correct next step is to confirm whether your town follows county zoning and then ask county planning staff how an ADU is classified in your zoning district and whether detached units are allowed at all before proceeding to building plans.
Does St. Croix County Allow ADUs?
Yes, St. Croix County allows ADUs in unincorporated areas, but the county’s land-use framework reflects its fast-growing, semi-rural character near the Twin Cities. ADUs are generally treated as accessory residential uses and limited to one per lot, with owner occupancy typically required. Rather than encouraging detached cottage-style ADUs everywhere, the county often favors internal or attached configurations that do not increase perceived density beyond what the zoning district intends.
The next step for homeowners is to confirm zoning district, shoreland status, and wastewater capacity with county planning staff before assuming an ADU will be approvable.
Does Ozaukee County Allow ADUs?
Ozaukee County can allow ADUs, but they are tightly controlled and strongly shaped by suburban and lakeshore development standards. In unincorporated areas, ADUs are generally reviewed under accessory use provisions and residential density limits rather than a dedicated ADU ordinance. Only one ADU per parcel is typically allowed, and owner occupancy is often required to prevent conversion into a de facto duplex.
Because Ozaukee County has many municipalities with their own zoning authority, county rules may not apply at all if your property is inside a city or village. Where county zoning does apply, setbacks, lot coverage, and proximity to Lake Michigan or other regulated shoreland areas are common constraints. The next step is to confirm jurisdiction first, then ask county zoning staff whether a second dwelling unit is allowed in your specific district and whether it must be internal, attached, or can be detached.
Does Dodge County Allow ADUs?
Dodge County allows ADUs in some unincorporated areas, but approval depends heavily on the zoning district and existing infrastructure. The county generally treats ADUs as accessory residential units rather than independent dwellings, with limits on number and scale to preserve low-density development patterns. Detached ADUs may be restricted or require additional approval, especially in agricultural or rural residential zones.
The next step is to verify your zoning district and septic capacity with county zoning staff before investing in architectural or engineering work.
Does Jefferson County Allow ADUs?
Jefferson County can allow ADUs, but they are evaluated through existing zoning and land-use standards rather than a single, countywide ADU policy. ADUs are typically limited to one per parcel and must remain subordinate to the primary dwelling. Owner occupancy is often expected, and the county tends to favor configurations that clearly read as part of a single-family property rather than a second standalone home.
Shoreland zoning, floodplain regulations, and minimum lot area requirements frequently shape what is possible in Jefferson County, particularly near rivers and lakes. Detached ADUs may face additional scrutiny compared to internal or attached units. The correct next step is to consult county planning staff to determine whether an ADU is allowed in your district and what approvals are required.
Does Manitowoc County Allow ADUs?
Just like most Wisconsin counties, Manitowoc County allows ADUs in unincorporated areas, but they are handled conservatively and through existing zoning frameworks rather than a countywide ADU-forward policy. ADUs are generally treated as accessory residential units, limited to one per parcel, and expected to remain clearly secondary to the primary dwelling.
You’ll need to directly contact either the zoning department or planning services, as online information is not readily available.
Does Wood County Allow ADUs?
Yes, Wood County can allow ADUs, but approval is highly dependent on zoning district and town-level participation in county zoning. The county generally evaluates ADUs under accessory use and residential density rules, meaning they are not automatically permitted everywhere. Only one ADU per parcel is typically allowed, and it must remain subordinate to the main residence rather than function as a separate standalone home.
For more information on standards and permits, we recommend reaching out to the zoning department to see how they can assist in the process.
Does Portage County Allow ADUs?
Following the pattern of the other Wisconsin counties, Portage County allows ADUs in unincorporated areas, but like many central Wisconsin counties, it relies on traditional zoning classifications rather than a modern ADU ordinance. ADUs are typically reviewed as accessory residential units and are limited to one per parcel. Owner occupancy is often expected, and the unit must remain clearly secondary in scale and function to the primary dwelling.
Does Chippewa County Allow ADUs?
It is unlikely. Chippewa County can allow ADUs, but the county’s approach is cautious and strongly tied to zoning district intent. ADUs are generally treated as accessory uses and limited to one per lot, with owner occupancy commonly required. Rather than encouraging detached backyard cottages broadly, the county often favors internal or attached units that do not substantially change residential density. You can contact the local planning department to make your case for why you are buying an ADU and see if you can utilize a conditional use permit to make it possible.
Does Sauk County Allow ADUs?
Yes, Sauk County allows ADUs in certain unincorporated areas, but they are closely regulated to maintain rural character and manage growth near environmentally sensitive areas. The county often evaluates ADUs through existing residential and accessory use standards rather than a single ADU-specific section.
Bluff protection, shoreland zoning, and minimum lot size requirements are especially important in Sauk County and frequently shape what is possible on a given parcel. To get through this, you will have to directly contact the zoning department and lay out your plans for the ADU.
Does Columbia County Allow ADUs?
Yes, in some areas, Columbia County but approval depends heavily on the zoning district and the county’s strong emphasis on land-use controls tied to growth management and environmental protection. There aren’t any specific regulations for ADUs spelled out in the zoning codes or available online. The next step is to confirm whether your town participates in county zoning and then consult county zoning staff to determine whether a second dwelling unit is allowed in your zoning district and what approvals are required.
Does Calumet County Allow ADUs?
Calumet County can allow ADUs, but they are regulated cautiously and evaluated within the context of traditional residential zoning rather than a modern, ADU-specific ordinance. ADUs are generally limited to one per parcel and must remain clearly accessory to the main dwelling. Owner occupancy is often expected, and the county tends to favor internal or attached units over detached backyard structures, especially in lower-density districts.
Agricultural zoning, minimum lot area requirements, and private wastewater system capacity are frequent constraints in Calumet County. Detached ADUs may require additional review or may not be permitted in certain districts at all. The correct next step is to identify your zoning district and contact county planning staff to confirm whether an ADU is allowed, what form it may take, and what permitting steps apply.
Does Grant County Allow ADUs?
Grant County allows ADUs in unincorporated areas under certain conditions, but the county’s land-use framework is strongly shaped by agricultural preservation and rural development controls. ADUs are typically treated as accessory residential uses and limited to one per parcel, with an emphasis on keeping the unit subordinate in size and appearance to the primary home. Owner occupancy is commonly required to prevent the creation of multiple standalone dwellings on a single lot.
Topography, floodplain areas, and private septic system requirements frequently determine whether an ADU is feasible, especially in the county’s hilly and river-adjacent regions. Detached units may require conditional approval depending on the zoning district. The next step is to confirm zoning classification and consult county zoning staff to clarify whether a second dwelling unit is allowed and what dimensional and permitting standards apply.
Does Waupaca County Allow ADUs?
Waupaca County can allow ADUs, but approval is closely tied to zoning district intent and whether the town has adopted county zoning. ADUs are generally evaluated as accessory residential units and limited to one per parcel, with owner occupancy commonly expected. The county tends to approach ADUs conservatively, favoring solutions that do not significantly alter residential density or rural character.
Lake and shoreland regulations are especially influential in Waupaca County and often restrict placement, size, and setbacks for any additional dwelling unit. Septic capacity and minimum lot size are also frequent hurdles. The best next step is to confirm jurisdiction, identify your zoning district, and speak with county zoning staff to determine whether an ADU is allowed and what approvals are required before moving forward.
Does Barron County Allow ADUs?
Barron County allows ADUs in certain unincorporated areas, but they are handled through existing zoning and accessory use standards rather than a standalone ADU ordinance. ADUs are typically limited to one per parcel and must remain subordinate to the primary residence, with owner occupancy often required. Detached ADUs may be permitted in some districts but are more closely reviewed for compatibility with surrounding land uses.
Shoreland zoning, wetlands, and private wastewater system requirements frequently shape what is possible in Barron County, particularly in lake-rich areas. Even when zoning allows an ADU, site constraints can limit size or placement. The next step is to identify whether your property is under county or town zoning and then consult county planning staff to confirm whether an ADU is allowed in your district and what dimensional and permitting standards apply.
Does Monroe County Allow ADUs?
Different county, same story. Monroe County allows ADUs in unincorporated areas, but they are regulated through the county’s existing zoning framework rather than a simplified ADU ordinance. ADUs are generally treated as accessory residential units and limited to one per parcel, with the expectation that the unit remains clearly secondary to the primary dwelling. The next step is to confirm whether your town participates in county zoning and then consult county zoning staff to determine whether a second dwelling unit is allowed in your specific district and what approvals are required.
Does Dunn County Allow ADUs?
Dunn County can allow ADUs, but approval is closely tied to zoning district intent and the county’s emphasis on maintaining rural land-use patterns outside incorporated areas. ADUs are typically evaluated as accessory residential uses, limited to one per parcel, and required to remain subordinate in scale and appearance to the primary home. Owner occupancy is often expected to prevent conversion into multiple independent dwellings.
Environmental considerations play a significant role in Dunn County, especially shoreland zoning along rivers and lakes and requirements for private wastewater systems. Detached ADUs may face additional review or may not be permitted in certain districts. The correct next step is to identify your zoning district and speak with county planning staff to confirm whether an ADU is allowed and what dimensional and permitting standards apply.
Does Polk County Allow ADUs?
Just like other Wisconsin counties, Polk County allows ADUs in some unincorporated areas, but the county’s approach is cautious and shaped by a mix of rural residential and recreational land-use priorities. ADUs are generally treated as accessory residential units and limited to one per parcel, with an emphasis on keeping the unit secondary to the primary dwelling. There aren’t guidelines on sizing or setback requirements.
The next step is to confirm jurisdiction and zoning classification, then consult county zoning staff to determine whether a second dwelling unit is permitted and what approvals are needed.
Does Douglas County Allow ADUs?
Douglas County can allow ADUs in unincorporated areas, but they are evaluated through traditional zoning and density controls rather than a dedicated ADU policy. ADUs are typically limited to one per parcel and must remain accessory to the primary residence, with owner occupancy often expected. The county’s regulatory environment reflects its combination of rural land, forested areas, and proximity to Lake Superior.
The next step is to confirm whether your property is subject to county zoning or town zoning and then consult county planning staff to clarify whether an ADU is allowed in your district and what the permitting process entails.
Does Pierce County Allow ADUs?
It is a difficult process, but it is possible. Pierce County allows ADUs in certain unincorporated areas, but approval is highly dependent on the zoning district and the county’s emphasis on managing growth along river corridors and near the Twin Cities metro edge.
Bluff protection, shoreland zoning, and private septic system capacity often shape what is possible in Pierce County more than unit size alone. Detached ADUs may require additional review or may be prohibited in some districts. The correct next step is to identify your zoning district and consult county zoning staff to determine whether an ADU is allowed on your parcel and what dimensional and permitting standards apply.
Does Marinette County Allow ADUs?
In Marinette County, ADUs are typically limited to one per parcel and must remain clearly subordinate to the primary residence. Owner occupancy is commonly required, and the county tends to view ADUs as a way to house family members rather than introduce additional rental density in rural areas. This means an ADU here will most likely not be allowed to rent out to additional persons. The next step is to confirm whether your town participates in county zoning and then consult county zoning staff to verify whether a second dwelling unit is allowed in your district and what approvals are required.
Does Shawano County Allow ADUs?
Shawano County can allow ADUs, but they are tightly tied to zoning district intent and the county’s focus on maintaining rural and agricultural land-use patterns. ADUs are generally treated as accessory residential units, limited to one per parcel, and expected to remain secondary in size and function to the main home. Owner occupancy is often required, and detached ADUs may face additional scrutiny depending on location.
Lake density controls, minimum lot size requirements, and septic capacity are common constraints in Shawano County, especially near recreational lakes. These factors frequently matter more than the size of the ADU itself. The best next step is to identify your zoning district and contact county zoning staff to confirm whether an ADU is allowed and whether it must be internal, attached, or can be detached.
Does Oconto County Allow ADUs?
Oconto County allows ADUs in certain unincorporated areas, but approval depends heavily on zoning district and proximity to shoreland areas. ADUs are typically evaluated as accessory residential uses and limited to one per parcel, with owner occupancy commonly expected. The county’s approach emphasizes keeping the unit subordinate to the primary dwelling and compatible with surrounding rural development.
Shoreland zoning along rivers, lakes, and Green Bay often imposes stricter setbacks and limits on placement, which can significantly affect detached ADU feasibility. Septic capacity is another frequent hurdle. The next step is to confirm whether your property is under county zoning and then speak with county planning staff to determine whether an ADU is allowed in your zoning district and what dimensional and permitting standards apply.
Does Oneida County Allow ADUs?
Oneida County can allow ADUs, but they are reviewed carefully due to the county’s heavy concentration of lakes, forestland, and environmentally sensitive areas. ADUs are generally treated as accessory residential units, limited to one per parcel, and required to remain secondary to the primary home. Owner occupancy is often expected, particularly in low-density residential and rural districts.
Shoreland zoning, minimum lot size, and wastewater system capacity frequently determine feasibility more than zoning permission alone. Detached ADUs may be restricted or require additional approval depending on district and environmental overlays. The correct next step is to confirm zoning classification and shoreland status, then consult county zoning staff to clarify whether a second dwelling unit is allowed and what approvals are required.
Does Green County Allow ADUs?
Based on available online information, Green County allows ADUs in some unincorporated areas, but they are handled through traditional zoning and accessory use standards rather than a streamlined ADU policy. ADUs are typically limited to one per parcel and must remain subordinate to the primary dwelling. Detached ADUs may face additional review or may not be permitted in certain zoning districts. The next step is to identify whether your town participates in county zoning and then consult county zoning staff to confirm whether an ADU is allowed and what dimensional and permitting requirements apply.
Does Clark County Allow ADUs?
Clark County can allow ADUs in unincorporated areas, but they are reviewed through traditional zoning and density controls rather than a modern ADU-focused ordinance. ADUs are generally treated as accessory residential units, limited to one per parcel, and expected to remain clearly secondary to the primary dwelling. Owner occupancy is commonly required, and the county tends to be cautious about detached ADUs in rural and agricultural districts where maintaining low residential density is a priority.
Private septic system capacity and minimum lot size are often the deciding factors in Clark County, especially outside incorporated areas. Even when zoning allows an ADU in principle, insufficient wastewater capacity can stop a project. The next step is to confirm whether your town follows county zoning and then consult county zoning staff to determine whether a second dwelling unit is allowed in your zoning district and what approvals are required.
Does Vernon County Allow ADUs?
Vernon County allows ADUs in some unincorporated areas, but approval is strongly shaped by the county’s rugged topography and emphasis on land conservation. ADUs are typically treated as accessory residential uses, limited to one per parcel, and required to remain subordinate in size and appearance to the primary home. Owner occupancy is often expected, and detached ADUs may face additional scrutiny due to slope, access, and site stability concerns.
Bluff protection, floodplain rules, and septic capacity are especially important in Vernon County and frequently determine feasibility more than zoning permission alone. Placement and access can be just as challenging as size limits. The next step is to identify your zoning district and consult county zoning staff to confirm whether an ADU is allowed and what site-specific standards must be met.
Does Trempealeau County Allow ADUs?
Trempealeau County can allow ADUs, but they are evaluated conservatively within the county’s existing zoning framework. ADUs are generally limited to one per parcel and must remain accessory to the primary dwelling, with owner occupancy commonly required. The county’s approach reflects a desire to accommodate family housing needs without significantly increasing rural residential density.
Environmental overlays play a major role in Trempealeau County, particularly along the Mississippi River corridor and other waterways. Shoreland zoning, floodplain regulations, and wastewater system capacity often dictate whether an ADU can be approved. The correct next step is to confirm jurisdiction, identify your zoning district, and speak with county zoning staff to clarify whether an ADU is permitted and what approvals are required.
Does Door County Allow ADUs?
Door County allows ADUs in certain unincorporated areas, but they are carefully regulated to protect the county’s unique coastal and tourism-driven character. ADUs are typically treated as accessory residential units and limited to one per parcel, with owner occupancy often required. The county is particularly cautious about detached ADUs that could function as short-term rentals rather than long-term housing.
Shoreland zoning along Lake Michigan and Green Bay, minimum lot size requirements, and septic capacity are frequent limiting factors in Door County. These regulations often have a greater impact on feasibility than the ADU concept itself. The next step is to confirm whether your property is under county zoning or municipal zoning and then consult county planning staff to determine whether an ADU is allowed and what dimensional and permitting standards apply.
Does Lincoln County Allow ADUs?
Lincoln County can allow ADUs in unincorporated areas, but approval depends heavily on zoning district and the county’s emphasis on managing growth in forested and rural landscapes. ADUs are generally treated as accessory residential uses, limited to one per parcel, and required to remain subordinate to the primary dwelling. Owner occupancy is commonly expected.
Environmental considerations, including wetlands, shoreland zoning, and private wastewater system capacity, frequently shape what is possible in Lincoln County. Detached ADUs may be restricted or require additional review depending on location. The next step is to identify your zoning district and consult county zoning staff to confirm whether an ADU is allowed on your parcel and what approvals are required.
Does Juneau County Allow ADUs?
Juneau County allows ADUs in some unincorporated areas, but they are reviewed through standard zoning and land-use controls rather than a dedicated ADU ordinance. ADUs are typically treated as accessory residential units, limited to one per parcel, and expected to remain clearly secondary to the primary dwelling. Owner occupancy is commonly required, and detached ADUs may be restricted depending on the zoning district, especially in rural or agricultural areas.
If you’re considering an ADU in Juneau County, expect a zoning review first to confirm whether a second dwelling unit is allowed in your district, followed by a building permit if approved. Your next step is to contact the county zoning office with your parcel number and ask how ADUs are classified in your district and whether detached units are permitted before moving forward with design or construction plans.
Does Waushara County Allow ADUs?
Waushara County can allow ADUs, but approval is closely tied to zoning district intent and the county’s emphasis on preserving rural character. ADUs are generally limited to one per parcel, must remain subordinate to the primary residence, and often require owner occupancy. The county tends to view ADUs as a supplemental housing option rather than a way to increase residential density.
Homeowners should expect to start with zoning confirmation to determine whether an ADU is allowed in their specific district, followed by a building permit and inspections if the use is approved. The best next step is to contact the county zoning department to confirm eligibility and ask what form of ADU—internal, attached, or detached—is allowed on your property.
Does Iowa County Allow ADUs?
Iowa County allows ADUs in certain unincorporated areas, but they are regulated through traditional zoning standards rather than a countywide ADU policy. ADUs are typically treated as accessory residential uses, limited to one per parcel, and expected to remain secondary in size and appearance to the main dwelling. Owner occupancy is commonly required, and detached units may face additional review.
The approval process usually begins with confirming zoning district rules and whether a second dwelling unit is permitted on a single-family lot. From there, homeowners should expect a zoning review and a building permit process if the ADU is allowed. The next step is to contact the county zoning office with your address or parcel number to understand what approvals apply before planning construction.
Does Vilas County Allow ADUs?
Following the pattern of other Wisconsin counties. Vilas County can allow ADUs, but regulations are shaped heavily by environmental protections and low-density development goals. ADUs are generally limited to one per parcel, treated as accessory residential units, and often require owner occupancy. Detached ADUs may be restricted, particularly near lakes or in environmentally sensitive areas.
If you’re pursuing an ADU in Vilas County, expect to confirm zoning and shoreland status early in the process. Approval typically involves zoning verification first, followed by building permits and inspections. The next step is to contact county zoning staff to determine whether an ADU is allowed on your parcel and what basic standards apply before committing to plans.
Does Adams County Allow ADUs?
Adams County allows ADUs in some unincorporated areas, but they are reviewed conservatively through existing zoning and residential density rules. ADUs are typically limited to one per parcel and must remain accessory to the primary dwelling, with owner occupancy commonly required. Detached ADUs may be limited or require additional approval depending on the zoning district. Because there is no guidance on sizing or other standards, we recommend reaching out directly to the zoning department. They can help guide you in the process.
Does Jackson County Allow ADUs?
According to available information, Jackson County allows ADUs in some unincorporated areas, but they are reviewed through standard zoning and density rules rather than a standalone ADU program. Detached ADUs may be restricted depending on the zoning district, particularly in rural or agricultural areas where residential density is closely managed.
If you’re considering an ADU in Jackson County, expect to start with a zoning determination to confirm whether a second dwelling unit is allowed in your district. From there, the process usually moves to a building permit and inspections if approved. The next step is to contact the county zoning office with your parcel information and ask how ADUs are classified in your zoning district and what approvals are required.
Does Kewaunee County Allow ADUs?
It is possible that Kewaunee County may allow ADUs, but approval is shaped by the county’s strong agricultural base and emphasis on low-density development. ADUs are generally treated as accessory residential units, limited to one per parcel, and expected to remain clearly secondary to the main home. Owner occupancy is commonly required, and detached ADUs may face additional restrictions depending on location and zoning.
Homeowners should expect an approval path that begins with confirming zoning eligibility and whether an ADU is allowed by right or requires special approval. If allowed, a building permit and inspections follow. The correct next step is to contact the county zoning department to confirm how an ADU is defined in your district and what form such as internal, attached, or detached is permitted.
Does Taylor County Allow ADUs?
Taylor County allows ADUs in certain unincorporated areas, but they are handled conservatively under existing zoning standards rather than a modern ADU ordinance. ADUs are typically limited to one per parcel, must remain accessory to the primary dwelling, and often require owner occupancy. Detached ADUs may be restricted in rural districts where maintaining low residential density is a priority.
If you’re planning an ADU in Taylor County, expect to begin with a zoning review to confirm whether a second dwelling unit is permitted on your property. Approval generally proceeds through zoning confirmation followed by a building permit if allowed. The next step is to contact county zoning staff with your address or parcel number to understand what standards apply before designing the unit.
Does Langlade County Allow ADUs?
Langlade County can allow ADUs, but the county’s heavily forested and rural character shapes how they are regulated. ADUs are generally treated as accessory residential uses, limited to one per parcel, and required to remain subordinate to the primary home. Owner occupancy is commonly expected, and detached ADUs may be restricted depending on the zoning district.
The approval process typically starts with confirming zoning district rules and whether an ADU is permitted in that district. If allowed, homeowners should expect a building permit and inspections to follow. The best next step is to contact the county zoning office to verify how ADUs are treated on your parcel and what approvals are required before moving forward.
Does Green Lake County Allow ADUs?
Green Lake County allows ADUs in some unincorporated areas, but they are regulated through traditional zoning and accessory use standards rather than a simplified ADU policy. ADUs are usually limited to one per parcel, must remain accessory to the primary dwelling, and often require owner occupancy. Detached ADUs may be more restricted near lakes or in lower-density zoning districts.
If you’re pursuing an ADU in Green Lake County, expect to start by confirming zoning eligibility and whether your property is subject to additional shoreland or land-use rules. The process generally includes zoning approval first, followed by a building permit if the use is allowed. The next step is to contact county zoning staff with your parcel information to clarify what’s permitted and what the review process looks like.
Does Sawyer County Allow ADUs?
Sawyer County allows ADUs in some unincorporated areas, but the conversation here usually starts with land use context rather than housing policy. Because much of the county is forested and recreational, ADUs are typically framed as accessory residential units intended for family use, not independent development. Only one ADU per parcel is generally allowed, it must remain secondary to the primary home, and owner occupancy is commonly expected.
If you’re pursuing an ADU in Sawyer County, expect the process to begin with a zoning classification check. The practical next step is to contact the county zoning office early and ask how a second dwelling unit is treated in your zoning district before investing in plans.
Does Richland County Allow ADUs?
Yes, Richland County can allow ADUs, but the county’s approach is shaped by terrain, floodplain concerns, and agricultural land protection rather than housing expansion. Expect only one ADU allowed per lot and the owner will have to occupy one of the properties on the lot.
The approval process in Richland County tends to focus on site suitability. Expect zoning review first, followed by building permits if the use is allowed. Floodplain or slope conditions may trigger additional review even when zoning supports an ADU. The next step is to contact county zoning staff with your parcel information and ask whether a second dwelling unit is permitted and what site-specific issues may affect approval.
Does Burnett County Allow ADUs?
The online information doesn’t clearly outline it one way or the other. Burnett County allows ADUs in certain unincorporated areas, but they are regulated cautiously due to the county’s large number of lakes and seasonal properties. ADUs are typically treated as accessory residential units, limited to one per parcel, and often tied to owner occupancy requirements to prevent conversion into short-term rentals or multi-unit use.
If you’re planning an ADU in Burnett County, expect the process to emphasize shoreland zoning and wastewater capacity early on. Approval usually starts with zoning confirmation, followed by a building permit if the ADU is allowed. The best next step is to contact the county zoning department to confirm whether your property’s zoning and shoreland status allow an ADU and what form it may take.
Does Lafayette County Allow ADUs?
It is unclear at this point. Lafayette County can allow ADUs, but they are evaluated within a land-use framework that prioritizes agricultural preservation and low-density development. ADUs are generally treated as accessory residential uses, limited to one per parcel, and expected to remain clearly secondary to the primary dwelling. Homeowners should expect an approval path that begins with confirming whether a second dwelling unit is allowed in their zoning district, followed by standard building permits if approved. The next step is to contact county zoning staff to ask how ADUs are defined locally and what approvals apply before proceeding with design or construction.
Does Washburn County Allow ADUs?
Just like many other Wisconsin counties, Washburn County allows ADUs in some unincorporated areas, but the county’s rural and lake-oriented character plays a major role in how they are regulated. ADUs are typically limited to one per parcel and must remain accessory to the primary residence, with owner occupancy often expected. Detached ADUs may be restricted or require additional scrutiny depending on zoning and proximity to water bodies. The correct next step is to contact the county zoning office to confirm eligibility and understand what approvals will be required.
Does Bayfield County Allow ADUs?
In Bayfield County, ADUs are approached cautiously because land-use rules are shaped as much by shoreline protection as by housing needs. ADUs may be allowed in unincorporated areas, typically as accessory residential units limited to one per parcel and required to remain secondary to the primary home. Owner occupancy is commonly expected, and detached ADUs can be restricted depending on zoning district and proximity to Lake Superior or inland lakes.
Homeowners should expect the process to start with confirming zoning district and shoreland status, since those two factors often determine feasibility before size or layout is even discussed. The next step is to contact county zoning staff with your parcel number and ask whether a second dwelling unit is permitted in your district and what approvals are required before applying for a building permit.
Does Ashland County Allow ADUs?
As of now, Ashland County’s treatment of ADUs reflects its mix of small communities and environmental protections rather than an explicit push for added housing units. This doesn’t mean they are outlawed, but the process may be difficult, and will probably involve a conditional use permit.
If you’re considering an ADU in Ashland County, expect zoning confirmation to be the first checkpoint, followed by building permits if the use is allowed. Properties near water or wetlands may involve additional review. The practical next step is to contact the county zoning office to confirm whether ADUs are permitted in your zoning district and what the approval process looks like.
Does Crawford County Allow ADUs?
Unfortunately it’s just not clear enough for us to provide concrete information. Crawford County looks at ADUs through the lens of land stewardship and terrain management rather than housing density. If they are permitted, they are limited to one per lot and usually dictated by owner occupancy requirements.
Because the county includes significant bluff, floodplain, and river corridor areas, the approval process often emphasizes site conditions early. Homeowners should expect to confirm zoning eligibility first and then move into building permits if allowed. The next step is to contact county zoning staff to ask whether a second dwelling unit is permitted on your parcel and what site-related issues may affect approval.
Does Marquette County Allow ADUs?
Following other Wisconsin counties, ADUs may be allowed in some unincorporated areas as accessory residential units, generally limited to one per parcel and expected to remain clearly secondary to the primary residence. Owner occupancy is often required, and detached ADUs may be limited depending on the zoning district. To find out specific details, you will have to directly contact the zoning department as there is limited online information to work with.
Does Rusk County Allow ADUs?
Rusk County regulates ADUs within a framework designed to maintain low-density rural development rather than encourage additional housing units. ADUs can be allowed in certain unincorporated areas, usually limited to one per parcel and treated as accessory to the main dwelling. Owner occupancy is commonly required, and detached ADUs may face additional scrutiny in agricultural or forest zoning districts.
Homeowners should expect a straightforward but cautious process: zoning confirmation first, followed by building permits if the use is allowed. Septic capacity and lot size often come up early in the discussion. The next step is to contact county zoning staff to ask how ADUs are classified in your zoning district and what approvals are required before planning construction.
Does Price County Allow ADUs?
When it comes to Price County, ADUs may be allowed in some unincorporated areas as accessory residential units, typically limited to one per parcel and expected to stay secondary to the primary dwelling. Owner occupancy is commonly required, and detached ADUs may be limited or reviewed more carefully depending on zoning district and land-use classification. The next step is to contact county zoning staff with your parcel information and ask how ADUs are treated locally and what approvals you should expect.
Does Buffalo County Allow ADUs?
There are many factors that govern the county’s approach. Buffalo County’s ADU rules are shaped by steep terrain, blufflands, and river corridor protections rather than housing demand alone. This means ADUs may be allowed in certain unincorporated areas, generally as accessory residential units limited to one per parcel and required to remain subordinate to the main home.
The approval process here often centers on site suitability before design details. Homeowners should expect zoning review first, followed by building permits if the ADU is allowed. For more information, we suggest contacting the planning department in your county.
Does Forest County Allow ADUs?
Forest County treats ADUs as a limited accessory use rather than a standard residential option, reflecting its heavily wooded, low-density character. ADUs may be allowed in some unincorporated areas, usually limited to one per parcel and expected to remain clearly secondary to the primary residence. Owner occupancy is commonly required, and detached ADUs may be restricted depending on the zoning district.
For the most clarity throughout the process, contact the zoning department and see what they have to say about it.
Does Pepin County Allow ADUs?
It isn’t clearly laid out. ADUs may be allowed in unincorporated areas as accessory residential units, typically limited to one per parcel and required to remain subordinate to the main dwelling. Owner occupancy is commonly expected, and detached units may face additional review.
Given the county’s riverfront areas and small parcel sizes, zoning confirmation is usually the first step in the process. If an ADU is allowed, homeowners can expect to move through standard building permits and inspections. The next step is to contact county zoning staff with your parcel number to confirm whether a second dwelling unit is permitted and what constraints apply.
Does Iron County Allow ADUs?
Iron County’s ADU framework reflects its remote, rural setting and limited infrastructure rather than a push for expanded housing options. ADUs can be allowed in certain unincorporated areas, generally limited to one per parcel and treated as accessory to the primary residence. Owner occupancy is often required, and detached ADUs may be restricted in some zoning districts.
Homeowners should expect an approval process that starts with zoning verification and moves into building permits if the ADU is allowed. The next step is to contact county zoning staff to confirm how ADUs are classified in your district and what approvals are required before moving forward.
Does Florence County Allow ADUs?
Just like other WI counties, Florence County takes a conservative, land-use-driven approach to ADUs that mirrors its small population and rural character. ADUs may be allowed in some unincorporated areas as accessory residential units, typically limited to one per parcel and expected to remain secondary to the primary home. Owner occupancy is commonly required, and detached units may face additional limitations.
If you’re planning an ADU in Florence County, expect to begin with a zoning determination to see whether a second dwelling unit is permitted in your district. If approved, the process usually continues with building permits and inspections. The next step is to contact county zoning staff to clarify eligibility and understand what approvals apply to your property.
Does Menominee County Allow ADUs?
It depends. Menominee County operates under a unique governance structure, and land-use decisions, including ADUs, are handled differently than in most Wisconsin counties. ADU allowances depend on tribal land-use regulations rather than standard county zoning ordinances, and rules can vary significantly based on location and local policy priorities. ADUs may be possible, but they are not governed by the same frameworks used elsewhere in the state.
If you’re considering an ADU in Menominee County, the process starts with confirming which authority controls land use on your property and what housing types are permitted. Expect to work directly with the appropriate land-use or planning office to understand requirements, approvals, and permitting steps before proceeding with any design or construction plans.
Accessory Dwelling Unit Requirements by Municipality
Browse your town to see the more specific requirements for ADUs!
| Milwaukee | Home PageCode of Ordinances |
| Madison | Home PageZoning Code |
| Green Bay | Home PageManufactured & Mobile Home Codes |
| Kenosha | Home PageManufactured & Mobile Home Codes |
| Racine | Home PageBuilding Code |
| Appleton | Home Page |
| Waukesha | Home PageMobile Home Park Regulations |
| Eau Claire | Home PageBuilding Code |
| Oshkosh | Home PageBuilding Code |
| Janesville | Home PageMobile Home Park Regulations |
| West Allis | Home PageManufactured & Mobile Home Codes |
| La Crosse | Home PageMobile Home Park Regulations |
| Sheboygan | Home PageBuilding Regulations |
| Wauwatosa | Home PageZoning Ordinance |
| Fond du Lac | Home PageManufactured Home Installations |
Does Milwaukee, WI Allow ADUs?
Yes! Milwaukee allows ADUs, and the rules are fairly “codified” compared to most places. A detached ADU is treated like a small backyard home: it’s capped at 1,000 sq ft of maximum floor area, can be up to 24 ft tall, and it has to respect the city’s table-based setbacks.
Permitting-wise, Milwaukee homeowners typically deal with the Department of Neighborhood Services for zoning and building permits, and you’ll want your site plan and utility plan tight before you apply, because setbacks, alley conditions, and lot constraints are where applications get slowed down.
Does Madison, WI Allow ADUs?
Yes! Madison allows ADUs, and the city has leaned into making them a normal option rather than a rare exception. Madison’s adopted framework commonly points to practical caps like a 1,000 sq ft maximum footprint and a 25 ft height ceiling, with small but real setback expectations (for example, a 3 ft rear/side type minimum).
Madison’s process is usually smoother if you start with the City zoning staff before final drawings. If you want the fastest path, your next step is to confirm your zoning district and ask staff what the controlling standards are for your parcel, then design to those numbers instead of guessing.
Does Green Bay, WI Allow ADUs?
Possibly, although Green Bay is more “it depends,” when it comes to ADUs. The city’s residential district standards show that accessory structures often work with modest setbacks (commonly 4 ft side/rear for accessory buildings in several contexts) and size limits that can land around 1,000 sq ft for detached accessory structures, while ADUs themselves may trigger extra review (commonly a conditional use permit).
If you’re serious about building one in Green Bay, don’t start by shopping floorplans, start by confirming whether your zoning district allows an ADU by right or requires a discretionary approval. The practical next step is contacting Green Bay Planning/Zoning with your address and whether you want internal/attached/detached.
Does Kenosha, WI Allow ADUs?
Here again, it’s unclear where Kenosha stands on ADUs. The city’s public-facing material is pointing more toward accessory-structure concepts and county-style “accessory living unit” ideas rather than a clearly cited, citywide ADU standard like Milwaukee’s. That usually means ADUs may be limited to certain districts or handled as a special use.
Your best next step in Kenosha is to treat this as a zoning-definition question first. Reach out to the City of Kenosha Planning/Zoning and ask what term the ordinance uses and whether detached backyard units are allowed in your district, and what the standards are for max size, height, and rear/side setbacks.
Does Racine, WI Allow ADUs?
Due to limited online information, it is difficult to confirm Racine’s stance on ADUs. If you’re in Racine, the smart move is to start with the City Development / Building Inspections side and ask whether ADUs are defined and allowed in your zoning district, and if yes, whether they’re treated as a permitted accessory use or require a special approval. This will provide clarity on your situation.
Does Appleton, WI Allow ADUs?
Appleton is another city where ADU rules may exist but aren’t consistently presented in one easy public summary the way some municipalities do. In Wisconsin, that usually means you can’t assume the neighboring city’s rules apply. Appleton may allow internal ADUs more readily than detached, or it may tie detached units to accessory-structure rules plus a zoning review.
For Appleton, the next step is straightforward. Contact Appleton Planning & Development and ask for the current ADU standard then confirm maximum unit size, required setbacks for detached structures used as dwellings, and parking/owner-occupancy requirements. Once you have those, your permit path is predictable.
Does Waukesha, WI Allow ADUs?
Possibly, but it’s not very clear yet. Waukesha has been active lately on “accessory building” standards, but that’s not automatically the same thing as allowing an accessory building to be a legal dwelling unit. There isn’t written legislation for ADUs, but under a conditional use permit, they are very possible.
If you’re trying to do an ADU in Waukesha, don’t treat it like a shed-plus-plumbing. Your next step is to ask the Waukesha Zoning Department: “Can a detached accessory structure be approved as a dwelling unit in my zoning district?” If yes, then you immediately follow the controlling standards regarding size and setbacks.
Does Eau Claire, WI Allow ADUs?
It is moving in that direction! Eau Claire has been rewriting its zoning code and ADUs are explicitly part of that modernization effort, meaning the city is moving toward broader allowance of ADUs as a housing type, not just a rare exception. Because these rules are not set in place yet, you may have to wait before proceeding with ADU construction. Or go directly to Planning Services with a copy of your ideal floor plans and see if they can assist you.
Does Oshkosh, WI Allow ADUs?
Oshkosh is another city where ADU language is not used in any zoning ordinances, leaving you as the homeowner, responsible to find out more.
The best move in Oshkosh is to ask Planning Services how they classify what you want to build whether it be an internal accessory apartment, attached addition, detached backyard cottage, or conversion to a two-family use. Once they tell you the category, they can point you to the exact dimensional standards and permit steps.
Does Janesville, WI Allow ADUs?
It is unknown due to limited online information. In practice, Janesville may allow certain accessory units in certain districts or treat them as a special approval, but without concrete ordinances or policies, it’s hard to know for certain.
If you want a reliable answer in Janesville, your next step is to contact City of Janesville Planning/Zoning with your address and ask whether a second, independent dwelling unit is allowed on a single-family lot in your district, and if detached units are treated differently than internal/attached. Then request the exact dimensional limits because those are what decide feasibility.
Does West Allis, WI Allow ADUs?
While West Allis is very permit-forward as a city, they don’t have much information about permits and standards for ADUs.
So for West Allis, the next step is to go straight to Building Inspection / Zoning and ask whether an ADU is recognized as a permitted accessory use in your zoning district, and if so, whether the city uses a max-size cap (sq ft or % of the primary home) and which setback table applies (principal vs accessory). Once you have that, you’ll know whether you’re designing a real dwelling or something the city will treat as non-habitable accessory space.
Does La Crosse, WI Allow ADUs?
Yes, although it appears that the city follows the guidelines of the county, and doesn’t have separately published ordinances. At the county level, one detached ADU is allowed with conditions like owner-occupancy, limits on use (no business), no mobile homes/RVs as ADUs, and a location rule keeping it within 150 feet of the principal home, plus a size rule that the ADU’s habitable area can’t exceed the principal home’s habitable area.
Your next step is to confirm which jurisdiction you’re in and then ask the City planning office if there is an ordinance section that governs ADUs/accessory apartments. If you’re in the county,the county ordinance language is what you design to, and it’s worth discussing septic/lot-area requirements early because those can quietly block an ADU even when zoning says “yes.”
Does Sheboygan, WI Allow ADUs?
It sure does. Sheboygan allows ADUs, and the city’s rules are written in a “neighborhood character” style rather than just raw geometry. The biggest size takeaway is that the ADU is capped at 40% of the principal dwelling’s floor area (excluding any attached garage), only one ADU per lot is allowed, and the property must be owner-occupied.
Setbacks in Sheboygan aren’t stated as one universal number inside the ADU section and attached ADUs follow the principal structure setbacks of your zoning district while detached ADUs follow the accessory structure setbacks for your zoning district. That means your next step is to reach out to the Planning and Zoning Department to ask about how to proceed with permits.
Does Wauwatosa, WI Allow ADUs?
It’s unclear at this point. The information available online is limited and homeowners are left to directly contact the city. Your next step is to contact Wauwatosa Planning and ask for the exact ADU ordinance section and the standards that apply to your lot. Specifically, ask about the max ADU size, whether detached backyard cottages are allowed everywhere or only in certain districts, and whether owner-occupancy is required. Figuring these items out will make the process going forward much easier.
Does Fond du Lac, WI Allow ADUs?
Yes! Fond du Lac explicitly allows what it calls internal accessory dwelling units, and the city gives you actual numbers to design around. The unit must be at least 300 sq ft, it can’t exceed 800 sq ft, and it also can’t be more than 33% of the principal dwelling’s gross floor area. Additionally, it’s one internal ADU per lot, and it must be inside the main home (not a detached backyard structure under this definition.
Fond du Lac is the kind of place where the permitting success is mostly about showing compliance clearly. Your next step is to contact the city’s Fond du Lac Building Inspectionswith your house’s existing floor area and your proposed ADU layout so they can confirm you’re under the 800-sq-ft and 33% caps before you spend money on full construction drawings.
Searching for an ADU Builder Serving Wisconsin?
If you’ve made it this far congratulations! Wading through regulations and prep can be complicated, but the result is so worth it! With this new knowledge under your belt, the next step is partnering with a builder you know is reliable and able to support you throughout the whole process. Zook Cabins is pleased to announce we offer our decades of experience and expertise throughout the whole state of Wisconsin. Simply reach out to us and we will get the process started. Let’s make your ADU dreams a reality!