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File #: 89918    Version: 1 Name: Two Unit Detached ADU
Type: Ordinance Status: Passed
File created: 9/9/2025 In control: Attorney's Office
On agenda: 9/16/2025 Final action: 10/7/2025
Enactment date: 10/17/2025 Enactment #: ORD-25-00068
Title: Amending sections within Chapter 28 to allow detached Accessory Dwelling Units to have two units and not be included in maximum permitted use accessory structure size.
Sponsors: Satya V. Rhodes-Conway, John W. Duncan, Tag Evers, Derek Field, Yannette Figueroa Cole, Carmella Glenn, MGR Govindarajan, John P. Guequierre, Badri Lankella, Sabrina V. Madison, Dina Nina Martinez-Rutherford, Julia Matthews, Davy Mayer, Sean O'Brien, Will Ochowicz, Michael E. Verveer, Regina M. Vidaver
Attachments: 1. 2025-9-25-Staff Presentation to HPC.pdf, 2. Zoning Text Memo 10-6-25 ADU Duplexes and Accessory Structure Max.pdf, 3. Public Comment 10-03-25.pdf, 4. 2025-9-30-Staff Presentation-Community Meeting, 5. 091025-100625_CC_public_comments.pdf
Date Ver.Action ByActionResultAction DetailsMeeting DetailsWatch
10/7/20251 COMMON COUNCIL Adopt and Close the Public HearingPass Action details Meeting details Not available
10/6/20251 PLAN COMMISSION RECOMMEND TO COUNCIL TO ADOPT - PUBLIC HEARINGPass Action details Meeting details Not available
9/25/20251 HOUSING POLICY COMMITTEE Return to Lead with the Recommendation for ApprovalPass Action details Meeting details Not available
9/16/20251 PLAN COMMISSION Refer  Action details Meeting details Not available
9/16/20251 COMMON COUNCIL Referred for Public HearingPass Action details Meeting details Not available
9/9/20251 Attorney's Office Referred for Introduction  Action details Meeting details Not available
Fiscal Note
No City appropriation required.
Title
Amending sections within Chapter 28 to allow detached Accessory Dwelling Units to have two units and not be included in maximum permitted use accessory structure size.
Body
DRAFTER’S ANALYSIS: This proposal would allow detached Accessory Dwelling Unit (ADU) buildings to have two units, effectively becoming duplexes. The proposed change also adds provisions that the detached ADU units must be in a single structure, and that a single zoning lot also may not have both an attached ADU and a detached ADU. It would also remove the ADU’s footprint area from the maximum cumulative square footage allowed for permitted use accessory structures so that ADUs are treated differently than garages and sheds.

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The Common Council of the City of Madison do hereby ordain as follows:

1. Subdivision (a) entitled “Maximum Area Per Lot” of Subsection (1) of Section 28.131 entitled “Accessory Buildings and Structures on Lots Used Exclusively for Residential and Mixed-Use Purposes” of the Madison General Ordinances is amended as follows:

“(a) Maximum Area Per Lot. Total area of accessory buildings measured at ground floor may not exceed one thousand (1,000) square feet. A larger total building area may be allowed by conditional use approval. The footprint of accessory structures that contain accessory dwelling units shall not be included in the one thousand (1,000) square feet calculation.”


2. Section 28.151 entitled “Applicability” of the Madison General Ordinances is amended by amending therein the following:

“Accessory Dwelling Unit.
(a) The principal building shall not contain more than eight (8) dwelling units.
(b) No more than one (1) attached accessory dwelling unit or two (2) detached accessory dwelling units may be located on a zoning lot. The detached dwelling units must be in a single structure. A zoning lot may not have both an a...

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