Zoning & Size Limits
| Requirement | Los Angeles, CA | Portland, OR |
|---|
| Allowed Zones | All residential zones (R1, R2, R3, R4, R5, RD, RW, RE, RS, R | All residential zones |
| Max Size (Detached) | 1,200 sq ft | 800 sq ft or 75% of primary (whichever is less) |
| Max Size (Attached) | 1,200 sq ft or 50% of primary dwelling | 800 sq ft or 75% of primary living area (same cap as detached; no separate 1,000 sq ft limit) |
| Max Height | Detached: 16 ft base (18 ft within 1/2 mi of trans | 20 ft (outside setbacks); 15 ft (within setbacks) |
| Parking Required | No parking required (eliminated statewide by AB 68) | Optional |
| Owner Occupancy | Not required (CA state law — permanent, no sunset provision) | Not required |
Setback Requirements
| Setback | Los Angeles, CA | Portland, OR |
|---|
| Rear Setback | 4 ft for units ≤16 ft height | 5 feet |
| Side Setback | 4 ft for units ≤16 ft height | 0 feet with easement |
| Front Setback | Must meet primary dwelling front setback | 0 feet (alley lot) |
Permits & Timeline
| Detail | Los Angeles, CA | Portland, OR |
|---|
| Permit Timeline | 60-day ministerial review (state-mandated) | 30-45 days |
| Permit Fees | $4,000-$15,000 depending on size and type (plus 10% General Plan Maintenance Surcharge on permit fees as of June 9, 2026) | ~$1,900 permit and plan review; plus System Development Charges (SDCs) of about $19,000 - see impact fees |
| Impact Fees | Waived for units under 750 sq ft (state law) | SDCs total roughly $18,900 for a detached ADU (Parks ~$7,100 |
| Pre-Approved Plans | Yes — LA has a Standard Plan Program with pre-appr | Extensive pre-approved library available |
Construction Costs
| Cost | Los Angeles, CA | Portland, OR |
|---|
| Avg Build Cost | $150,000-$350,000 | $150,000-$300,000 |
| Cost Per Sq Ft | $200-$400 | $125-$250 |
| Garage Conversion | $80,000-$180,000 | $70,000-$160,000 |
| Prefab ADU | $100,000-$250,000 | $100,000-$240,000 |
Rental Income Potential
| Rental | Los Angeles, CA | Portland, OR |
|---|
| 1BR Avg Rent | $1,800-$2,500/mo | $1,400-$1,900/mo |
| 2BR Avg Rent | $2,200-$3,200/mo | $1,800-$2,600/mo |
| Short-Term Rentals | Restricted — STR rules apply; host must be primary resident | Yes, with registration |
| Est. ROI | 6-10% annual return | 6-9% annual return |
Which City Is Better for ADUs?
Los Angeles scores 9/10 while Portland scores 9/10 on our ADU-friendliness index.
Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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