Committee splits on accessory dwelling unit rules; advances version requiring special‑use approvals for internal ADUs in single‑family zones

The committee considered a substitute zoning ordinance to create a new limited use for accessory dwelling units (ADUs) and to set design and use standards across Milwaukee’s residential zoning districts. The discussion was the meeting’s most contested item and included multiple proposed substitutes before the committee advanced a version that requires a special‑use permit for internal ADUs in RS‑1 through RS‑6 single‑family districts.

What the ordinance would do: The adopted substitute (committee version) would create an ADU use with detailed limited‑use and design standards. Key elements include: one ADU per parcel; ADUs limited to parcels with existing single‑ or two‑family dwellings; owner occupancy at the time of ADU permit application (to limit investor‑driven builds); and separate design standards for detached (external), attached (addition) and internal ADUs (basement/attic conversions). All ADUs would still need to meet building‑code and health‑and‑safety requirements enforced by DNS/plan exam.

Special‑use rule for internal ADUs in single‑family zones: After extended debate, the committee substituted and recommended passage of a version that requires a special‑use permit for internal ADUs in RS‑1 through RS‑6 districts. Detached and attached ADUs remain permitted when they meet the ordinance’s limited use standards. Committee discussion focused on whether internal ADUs (most feasible and least expensive) should be allowed as‑of‑right and concerns that they could convert single‑family homes into practical multi‑family uses without neighborhood notice.

Implementation, building code and enforcement: DNS staff explained that building‑code triggers (fire separation, means of egress, sprinklers in some cases) make many internal ADUs technically costly or impractical, particularly for third‑floor conversions, but that basement and some attic conversions are feasible if they comply with fire separation and egress rules. DCD and DNS emphasized the ordinance does not change the building code; separate permits and plan review remain required.

Committee action: Committee members offered competing substitutes. One proposal would have prohibited internal ADUs in RS‑1 through RS‑6 (making them variance‑level items); the version the committee ultimately advanced requires a special‑use approval for internal ADUs in those districts. On the final recommended substitute, the recorded committee roll call showed three members in favor and two opposed; the committee advanced the ordinance to the council with the special‑use requirement for internal ADUs.

Why it matters: ADUs are a low‑rise, incremental housing tool that advocates say can add units and support aging in place. Opponents feared change in single‑family neighborhood character, potential conversion to short‑term rentals and a loss of local notice and aldermanic input. The committee’s special‑use compromise attempts to preserve a path to ADUs while creating a neighborhood notice and discretionary hearing for internal conversions in single‑family zones.

Ending: The ordinance as recommended will proceed to the full council. DCD and DNS said they will monitor implementation and return with refinements if issues arise.