Plan Commission approves zoning tweaks to ease single‑family upgrades, ADUs and small infill

The Madison Plan Commission unanimously recommended that the Common Council approve a package of zoning text amendments on Feb. 17 designed to make modest changes to single‑family and small residential infill rules, including rules for accessory dwelling units (ADUs).

Planning staff said the changes address regulatory obstacles staff encounters while administering the zoning code. Katie Bannon, the city zoning administrator, described six principal changes: (1) modify the attached‑garage facade requirement (replace a strict 2‑foot recessed requirement with a more flexible allowance so garage doors may extend up to 4 feet forward of the remainder of the facade while retaining a 50% maximum garage‑door width rule); (2) allow open porches to encroach up to 3 feet into required side yards so side‑oriented porches can be practical; (3) eliminate a one‑foot difference in required side setbacks between one‑story and taller buildings so setbacks are consistent regardless of stories; (4) align measurement and size limits for detached ADUs with accessory‑structure rules by setting a 1,000‑square‑foot footprint maximum for attached and detached ADUs and dropping the separate two‑bedroom limit; (5) add two additional allowed two‑unit building configurations (back‑to‑back and partial-stack/partial-side) to give designers more flexibility; and (6) remove the zoning code’s “usable open space” requirement (a prescriptive per‑unit private outdoor space rule) while retaining lot coverage, setback, landscaping and stormwater standards.

Staff said the intent is to reduce design and administrative friction that often prevents small-scale infill and ADUs from being feasible. Staff noted that Madison has issued relatively few ADU permits historically and that some administrative complexities — for example, floor‑area counting rules and bedroom counts — have made detached ADUs harder to permit. The footprint alignment and removal of the bedroom limit are intended to make detached ADUs simpler to design and review.

Public comments: Two registrants spoke. Grant Foster, who said he previously supported ADU development, urged the commission to consider two additional changes: slightly higher maximum height for detached accessory buildings (to ease roof‑form design for two‑story garage+ADU forms) and allowing a property to host a second ADU within the same permitted form to improve economics for detached ADUs. Foster said those changes would make detached ADUs more financially viable. Linda Leonard urged the commission to retain private usable open space for family needs and stressed that covenants and PD zoning in parts of the city limit where changes would have effect.

Commission action: Alder Yeager moved, Alder Duncan seconded a motion recommending approval of the staff package. Commissioner Wisniewski proposed and the commission accepted an amendment to the motion to increase the maximum permitted height for detached accessory structures/ADUs from 25 feet to 30 feet; that amendment was seconded and incorporated into the recommendation. The full package, as amended, passed unanimously.

Why it matters: The changes lower regulatory barriers to modest infill and to homeowners wishing to add ADUs, potentially expanding options for families and renters. Removing the usable‑open‑space requirement aims to reduce an infill obstacle while preserving other yard, lot‑coverage and stormwater protections.

What’s next: The commission’s recommendation will go to the Common Council for consideration. Staff said additional ADU refinements suggested by commenters (for example, allowing a second ADU on a lot) could be explored separately.

Votes at a glance: Motion to recommend approval of the zoning amendments package (as amended to allow 30‑foot detached accessory building height) — recommended to council, unanimous.