ADU Rules by City

Max size: 900 sq ft · Setbacks: 15 feet

Max size: 1,000 sq ft or 75% of primary dwelling (whichever is less); 500 sq ft for second/third ADU · Setbacks: 25 feet

Max size: 75% of primary dwelling, up to 1,000 sq ft (minimum 650 sq ft guaranteed) · Setbacks: 20 feet

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1200 sq ft · Setbacks: 4 ft minimum (detached new construction)

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1,200 sq ft · Setbacks: 4 ft for units ≤16 ft height

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1200 sq ft · Setbacks: 4 ft minimum

Max size: 1200 sq ft · Setbacks: 4 ft minimum (detached new construction)

Max size: 1200 sq ft; may reduce to 800 sq ft if lot coverage exceeded · Setbacks: 4 ft maximum (detached new construction)

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1200 sq ft; reduces to 800 sq ft if lot coverage exceeded · Setbacks: 4 ft minimum (detached new construction)

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1,200 sq ft (state minimum; local program caps at 850-1,000 sq ft) · Setbacks: 4 ft minimum

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 1,200 sq ft · Setbacks: 4 ft

Max size: 800 sq ft (market-rate); 1,000 sq ft (affordable ADU program) · Setbacks: 10 feet

Max size: 50% of principal dwelling or 1,250 sq ft (whichever is less); 750 sq ft max if principal < 1,500 sq ft · Setbacks: 12 feet

Max size: 864 sq ft · Setbacks: Must be within rear 35% of lot; 5 ft minimum rear setback

Max size: Greater of 30% of required rear yard OR 450 sq ft · Setbacks: Minimum 7.5 ft from alley centerline (if applicable)

Max size: 25% of primary residence or 750 sq ft (whichever is smaller) · Setbacks: 20 feet

Max size: 400-800 sq ft (varies by district) · Setbacks: 5 ft (RU-1 district)

Max size: 500-1,000 sq ft (varies by district and sector) · Setbacks: 15 feet

Max size: 950 sq ft maximum (750 sq ft threshold affects setback requirements) · Setbacks: 3 ft (ADUs ≤750 sq ft); 15-20 ft (ADUs >750 sq ft, varies by district)

Max size: 850 sq ft · Setbacks: 4-15 ft (varies by zone: 4 ft in R-5; 15 ft in R-4/R-4A)

Max size: 800 sq ft or 40% of principal dwelling (whichever is less) · Setbacks: 20 feet

Max size: 400 sq ft (3,500-4,999 sf lot); 800 sq ft (5,000+ sf lot) · Setbacks: Standard building code requirements

Max size: 700 sq ft (current pilot; new ordinance April 2026 removes size cap) · Setbacks: 15 feet

Max size: 1,000 sq ft · Setbacks: 12 feet

Max size: 900 sq ft or 50% of living area (whichever is less) · Setbacks: 20 feet

Max size: 950 sq ft · Setbacks: 15 feet

Max size: 850 sq ft · Setbacks: 20 feet

Max size: 1,300 sq ft or 16% of lot area (whichever greater); max 1,600 sq ft or size of primary dwelling (whichever less) · Setbacks: 3 ft (5 ft from alleys for above-garage ADUs)

Max size: 800 sq ft or 75% of principal dwelling floor area (whichever greater) · Setbacks: 3 ft from interior lot lines

Max size: 900 sq ft · Setbacks: 15 feet

Max size: Not allowed (dense urban) · Setbacks: N/A

Max size: 850 sq ft · Setbacks: 15 feet

Max size: 1,000 sq ft · Setbacks: 15 feet

Max size: 850 sq ft · Setbacks: 15 feet

Max size: 800 sq ft · Setbacks: 15 feet

Max size: 800 sq ft (first ADU); 500 sq ft (second ADU) · Setbacks: 10 feet

Max size: 1,100 sq ft · Setbacks: 10 feet

Max size: 800 sq ft or 75% of primary (whichever is less) · Setbacks: 5 feet

Max size: 1,050 sq ft · Setbacks: 12 feet

Max size: 1200 sq ft (proposed; not yet adopted) · Setbacks: Varies by zone; typically 20-30 ft

Max size: 1200 sq ft (but must not exceed footprint of primary structure) · Setbacks: 5 ft minimum

Max size: 1,350 sq ft or 0.15 FAR (whichever is smaller; updated by HOME Phase 2, May 2024) · Setbacks: 10 feet

Max size: 900 sq ft · Setbacks: 15 feet

Max size: 1,000 sq ft · Setbacks: 15 feet

Max size: 1,200 sq ft · Setbacks: 15 feet

Max size: 800 sq ft · Setbacks: 20 feet

Max size: No maximum size; height-limited · Setbacks: Increase 1 ft for each foot of height above 17 ft

Max size: 900 sq ft · Setbacks: 1 ft minimum; 3 ft if windows face property line

Max size: 1,000 sq ft · Setbacks: 5 ft (interior lots); 10 ft (corner lots)

Max size: 1,200 sq ft · Setbacks: 5 feet

Max size: 1,000 sq ft · Setbacks: 15 feet

Max size: 1,100 sq ft · Setbacks: 10 feet

Max size: 1,050 sq ft · Setbacks: 10 feet