Madison’s February 2025 zoning package amended selected ADU standards in Chapter 28. The amendment is dated; current code and district still determine a present project envelope.
Local standards
The selected local standards are summarized in the Ordinance ORD-25-00011, File 86650. The related source Legislation Detail — File 86650 provides the Legistar file and enactment record. The amended provision allows an ADU within a principal building up to 1,000 square feet and removes the former two-bedroom ceiling. An accessory building containing an ADU has a maximum footprint of 1,000 square feet. A detached ADU building is limited to 25 feet, measured as a principal building under §28.134(1)(b).
Confirm the applicable rule
Setbacks follow underlying-district accessory-building standards. The ordinance distinguishes unit floor area from building footprint. Check current MGO §28.151, applicable district, later amendments, and measurement; the redline’s struck-through text is not adopted. The City Legistar record gives March 9, 2025 as the enactment date. Zoning measurements do not by themselves establish fire separation, building-code compliance, utility capacity, or permit approval. For shared measurement methods, see the setback and separation guide and floor-area guide.
