Wisconsin 2025-2026 Regular Session

Wisconsin Assembly Bill AB449

Introduced
9/25/25  
Refer
9/25/25  
Report Pass
10/3/25  
Refer
10/3/25  

Caption

Local regulation of accessory dwelling units. (FE)

Impact

The introduction of AB449 is expected to influence local government zoning regulations by promoting the development of ADUs. By requiring municipalities to permit these structures, the bill seeks to ease housing shortages and encourage diverse living arrangements in established neighborhoods. The allowed conditions under which ADUs must be constructed, such as size limitations and adherence to local zoning requirements, aim to balance community concerns about density and property aesthetics while striving to enhance housing availability.

Summary

Assembly Bill 449 aims to establish new regulations regarding accessory dwelling units (ADUs) across the state. The bill mandates that all political subdivisions with zoning ordinances allow at least one ADU as a permitted use on parcels zoned for residential or mixed-use properties, provided these parcels have an existing single-family dwelling. The legislation is designed to facilitate the incorporation of ADUs into residential areas, thus potentially increasing affordable housing options in the state.

Contention

Notably, AB449 has sparked debates among stakeholders regarding its implications for local governance and property rights. Proponents argue that the bill will address housing shortages and promote sustainable growth, thereby benefiting communities as a whole. However, critics express concerns that enforced ADU regulations could undermine local control over zoning laws, limiting the ability of municipal authorities to tailor regulations to meet specific local needs. Moreover, the prohibition of short-term rentals for newly constructed ADUs raises questions about property owner rights and potential impacts on local housing markets.

Companion Bills

WI SB473

Crossfiled Local regulation of accessory dwelling units. (FE)

Previously Filed As

WI SB473

Local regulation of accessory dwelling units. (FE)

WI SB247

Local and private regulation of accessory dwelling units. (FE)

WI AB365

Local and private regulation of accessory dwelling units. (FE)

WI H627

Regulation of Accessory Dwelling Units

WI SB543

Accessory dwelling units and junior accessory dwelling units.

WI S1786

Concerns development of accessory dwelling units and related regulations.

WI SB1117

Accessory dwelling units and junior accessory dwelling units.

WI S495

Regulation of Accessory Dwelling Units

WI HB2783

Accessory dwelling units; population; regulations

WI SB673

Relating to municipal and county regulation of accessory dwelling units; authorizing a fee.

Similar Bills

CA AB1154

Junior accessory dwelling units.

CA SB9

Accessory Dwelling Units: ordinances.

NJ A3488

Concerns development of accessory dwelling units and related municipal land use regulations.

CA AB2127

Accessory dwelling units: private sewage disposal systems.

CA AB956

An act to amend Section 50515.

CA AB1055

Accessory dwelling units: proof of residential occupancy requirements.

CA SB543

Accessory dwelling units and junior accessory dwelling units.

NH HB577

Relative to modifying the definition of ADUs.