ADU Pass
Madison
Dane County portion
Also in: No County
ADU Pass helps homeowners in Madison, Dane County, Wisconsin navigate the permit paperwork for building an accessory dwelling unit. This area covers 13 ZIP codes.
Map
ADU details
ADU legality: unclear
Wisconsin leaves ADU regulation to local municipalities under home-rule or Dillon-rule authority. Madison permits ADUs subject to local conditions per its zoning ordinance.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 150 | $1,900 | $39,000 | $40,900 |
| 600 | 600 | $1,900 | $156,000 | $157,900 |
| midpoint | 525 | $1,900 | $136,500 | $138,400 |
| maximum | 900 | $1,900 | $234,000 | $235,900 |
Fee breakdown
Viability (permitted uses)
- Long-term rental: yes Long-term rental of ADU generally permitted; landlord-tenant law and any city rental-registration ordinance apply.
- Short-term rental: with-restrictions STR rules vary by city. Madison regulates STRs separately from ADU permitting; check local STR ordinance and HOA covenants.
- Office rental: with-restrictions Detached office rental requires home occupation permit or rezoning.
- Home office: yes Home occupation permitted with restrictions on signage and customer traffic.
- Studio / workshop: yes Personal artist studio is a permitted accessory use.
- Agriculture: with-restrictions Limited urban agriculture permitted in residential zones; livestock varies by district.
- Relative support: yes Family-occupancy ADU explicitly permitted in single-family zones.
Utilities
- Water: Madison Water Utility · 30d connect · $4,500
- Sewer: Madison Sewer / Wastewater · 30d connect · $5,500
- Electric: Madison Electric Utility · 21d connect · $1,800
- Gas: Madison Gas Utility · 30d connect · $1,500
Property values & taxes
Construction timeline
Realistic total: best 7mo · typical 10mo · worst 16mo
Financing
Insurance impact
HOA prevalence & preemption
Wisconsin's strong condominium / HOA-deference posture combines with the absence of state ADU preemption to produce a doubly-local regime: ADU rights depend on the municipality AND on the parcel's CC&Rs. Both must allow.
Regulatory overlays (1)
- historic-district
Madison historic districts trigger Architectural Review Board / Historic Preservation Commission review for ADUs in historic boundaries.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
Legal history (timeline)
Current ordinance: City of Madison Municipal Code — Accessory Dwelling Units, adopted 2020-01-01, last amended 2024-04-01
- 2024-01-01 — City of Madison ADU code refresh (city-ordinance)
Conforming local-code amendments aligning with current Wisconsin accessory-dwelling framework.
Effect: Codified permissive ADU standards consistent with state law and local zoning.
Dane County — county ADU rules and overlays
County ADU ordinance
Dane County administers the Dane County Zoning Ordinance (Chapter 10, Code of Ordinances) in unincorporated towns that have not adopted their own zoning, and reviews zoning amendments for towns that have adopted village powers under Wis. Stat. Sec. 60.61-60.62. Within incorporated cities and villages (notably Madison, Sun Prairie, Fitchburg, Middleton, Verona, McFarland, DeForest, Stoughton), the city's own zoning code controls and the county code does not apply. Accessory dwelling units are addressed in the county zoning ordinance with district-specific standards.
County regulatory overlays
Dane County administers two principal countywide overlays in unincorporated areas: (1) Dane County Shoreland Zoning Ordinance under Wis. Stat. Sec. 59.692, applying within 1,000 feet of the ordinary high-water mark of navigable lakes (including Lake Mendota, Lake Monona, Lake Waubesa, Lake Kegonsa) and 300 feet of navigable rivers/streams; and (2) FEMA NFIP-participating floodplain zoning. The shoreland overlay imposes setback, vegetation-buffer, and impervious-cover standards that materially affect ADU siting.
- Dane County Floodplain Zoning
- Dane County Shoreland Zoning — An ADU on a shoreland parcel is generally subject to the same setback and impervious-cover limits as a primary dwelling.
County permitting (unincorporated parcels)
Dane County Zoning Division reviews zoning compliance and the Dane County Department of Planning & Development administers building inspection in unincorporated towns under contract or county-administered programs. For a new ADU in unincorporated Dane County, an applicant typically (1) confirms the zoning district allows accessory dwellings, (2) obtains zoning approval (and conditional-use approval where required), (3) obtains a Wisconsin Uniform Dwelling Code (UDC) building permit through the town's contracted UDC inspector, and (4) for parcels not on public sewer, obtains a private onsite wastewater treatment system (POWTS) permit through Dane County Public Health.
Wisconsin state — ADU law and programs
State HOA preemption
Wisconsin's strong condominium / HOA-deference posture combines with the absence of state ADU preemption to produce a doubly-local regime: ADU rights depend on the municipality AND on the parcel's CC&Rs. Both must allow.
State financing programs
Wisconsin's state housing finance vehicle is the Wisconsin Housing and Economic Development Authority (WHEDA), established 1972. WHEDA does NOT publish a dedicated consumer ADU loan, but the 2023 affordable-housing package (Acts 14, 15, 16) created two NEW WHEDA-administered revolving loan funds that meaningfully touch ADU-adjacent financing: the Residential Housing Infrastructure Loan Fund (Act 14) and the Main Street Housing Rehabilitation Loan Fund (Act 15). Act 14 funds public-infrastructure costs (water, sewer, road) for workforce or senior housing development — useful where an ADU is added to a parcel that needs service upgrades. Act 15 funds rehabilitation of existing rental housing, which can include creating an ADU within an existing rental property; loan recipients accept a 10-year affordability covenant recorded against the property. WHEDA also continues to operate its mortgage-revenue-bond first-mortgage products (WHEDA Advantage, FHA Advantage, etc.) for first-time and qualified repeat homebuyers; ADU buildouts financed at acquisition typically combine a WHEDA first mortgage with an FHA 203(k) or Fannie Mae HomeStyle Renovation overlay.
State housing programs
Wisconsin's main state housing-supply program package is 2023 Acts 14, 15, and 16. Acts 14 and 15 are the WHEDA revolving loan funds (covered in stateFinancing). Act 16 made a procedural change of significance to ADU developers: it consolidated the certiorari-review pathway for local land-use decisions on residential-development applications, making Act 16's procedure the SOLE judicial-review pathway. This narrows the appeal vector and tightens timelines on local zoning denials, including ADU denials. Wisconsin has no statewide pre-approved ADU plan library and no statewide impact-fee waiver for ADUs (impact fees are governed by Wis. Stat. § 66.0617 with no ADU-specific carve-out). UniformCommercial Code adoption and the Wisconsin Uniform Dwelling Code (Wis. Admin. Code SPS 320–325) apply uniformly to all dwellings — there's no separate ADU code.
- Certiorari-review pathway for residential land-use decisions (2023 Wisconsin Act 16) — Establishes a new and EXCLUSIVE certiorari-review procedure for political-subdivision decisions on residential-development applications. Tightens timelines and limits the scope of judicial review, which affects any contested ADU permit denial or approval condition.
- Uniform Dwelling Code (Wisconsin Administrative Code SPS 320–325) — Statewide one- and two-family dwelling code administered by the Wisconsin Department of Safety and Professional Services. Applies uniformly to ADUs that meet the one- or two-family classification. Local building inspectors enforce; no statewide ADU-specific overlay.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Codes
- 53703
- 53704
- 53705
- 53706
- 53711
- 53713
- 53714
- 53715
- 53716
- 53717
- 53718
- 53719
- 53726
Post Office
- 205 Corporate Dr, 53714
- 3902 Milwaukee St, 53714
- 441 N Lake St, 53715
- 601 Sawyer Ter, 53705
- 733 Struck St, 53711
- 820 W Wingra Dr, 53715