summary
Introduced
10/02/2025
10/02/2025
In Committee
02/12/2026
02/12/2026
Crossed Over
Passed
Dead
Introduced Session
Potential new amendment
2025-2026 Regular Session
Bill Summary
This bill requires political subdivisions with zoning ordinances to allow as a permitted use at least one accessory dwelling unit (ADU) on each parcel that is zoned for residential use or mixed use on which an existing single-family dwelling is located. A permitted use under the bill is a use of property that complies with all requirements of the zoning district in which the property is located and for which no conditional use, variance, or special review or approval is required for an accessory dwelling unit. The bill specifically allows political subdivisions to 1) limit the size of an ADU to not larger than the square footage of the existing single-family dwelling, 2) limit the height of an ADU, other than an ADU that is a conversion of an existing legal nonconforming structure, to not greater than the maximum height permitted in the underlying zoning district, 3) require that an ADU satisfy current setback and lot coverage requirements, and 4) prohibit the use of an ADU created on a parcel after the effective date of the bill as a short-term rental. Because this bill may increase or decrease, directly or indirectly, the cost of the development, construction, financing, purchasing, sale, ownership, or availability of housing in this state, the Department of Administration, as required by law, will prepare a report to be printed as an appendix to this bill. LRB-4896/1 EVM:cdc&cjs 2025 - 2026 Legislature SENATE BILL 473 For further information see the local fiscal estimate, which will be printed as an appendix to this bill.
AI Summary
This bill requires local governments (counties, towns, and cities) to allow at least one accessory dwelling unit (ADU) as a permitted use on residential or mixed-use parcels with an existing single-family home. An ADU is defined as a separate residential unit with independent living facilities located on the same property as a primary single-family dwelling, which can be within, attached to, or detached from the main house, and may be created by converting an existing structure. The bill allows local governments to implement certain restrictions on ADUs, such as limiting the size to no larger than the square footage of the existing dwelling, restricting height to the maximum allowed in the zoning district, requiring adherence to current setback and lot coverage requirements, and prohibiting the use of newly created ADUs as short-term rentals. This legislation aims to increase housing flexibility and availability by making it easier for property owners to add secondary dwelling units to their existing residential properties, potentially providing more affordable housing options or opportunities for multigenerational living. The bill will take effect on the first day of the seventh month after its publication.
Committee Categories
Agriculture and Natural Resources
Sponsors (19)
Julian Bradley (R)*,
Rachael Cabral-Guevara (R)*,
Dan Feyen (R)*,
Kelda Roys (D)*,
Jamie Wall (D)*,
Elijah Behnke (R),
Lindee Brill (R),
Robert Brooks (R),
Joy Goeben (R),
Dan Knodl (R),
Rob Kreibich (R),
Scott Krug (R),
Dave Murphy (R),
Jerry O'Connor (R),
Lori Palmeri (D),
Jim Piwowarczyk (R),
Amaad Rivera-Wagner (D),
Rob Summerfield (R),
Chuck Wichgers (R),
Last Action
Representative Brown added as a cosponsor (on 03/06/2026)
Official Document
bill text
bill summary
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bill summary
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bill summary
| Document Type | Source Location |
|---|---|
| State Bill Page | https://docs.legis.wisconsin.gov/2025/proposals/reg/sen/bill/sb473 |
| Analysis - LC Amendment Memo | https://docs.legis.wisconsin.gov/document/lcamendmentmemos/2025/REG/SB473.pdf |
| SB473 ROCP for Committee on Insurance, Housing, Rural Issues and Forestry | https://docs.legis.wisconsin.gov/2025/related/records/senate/insurance_housing_rural_issues_and_forestry/1972580.pdf |
| Fiscal Note - SB473: Fiscal Estimate From DOR | https://docs.legis.wisconsin.gov/2025/related/fe/sb473/sb473_dor.pdf |
| Senate Amendment 1 | https://docs.legis.wisconsin.gov/document/amends/2025/REG/SB473-SA1.pdf |
| BillText | https://docs.legis.wisconsin.gov/document/proposaltext/2025/REG/SB473.pdf |
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