Zoning & Size Limits
| Requirement | Los Angeles, CA | Austin, TX |
|---|
| Allowed Zones | All residential zones (R1, R2, R3, R4, R5, RD, RW, RE, RS, R | SF3, SF2, SF1, MU, UR, etc. |
| Max Size (Detached) | 1,200 sq ft | 1,350 sq ft or 0.15 FAR (whichever is smaller; updated by HOME Phase 2, May 2024) |
| Max Size (Attached) | 1,200 sq ft or 50% of primary dwelling | 1,350 sq ft or 0.15 FAR (whichever is smaller) |
| Max Height | 25 ft (2 stories) for detached; varies for attache | 35 feet |
| Parking Required | No parking required (eliminated statewide by AB 68) | 1 space for primary, optional for ADU |
| Owner Occupancy | Not required (CA state law — permanent, no sunset provision) | Not required |
Setback Requirements
| Setback | Los Angeles, CA | Austin, TX |
|---|
| Rear Setback | 4 ft for units ≤16 ft height | 10 feet |
| Side Setback | 4 ft for units ≤16 ft height | 3 feet (with easement) |
| Front Setback | Must meet primary dwelling front setback | 20 feet |
Permits & Timeline
| Detail | Los Angeles, CA | Austin, TX |
|---|
| Permit Timeline | 60-day ministerial review (state-mandated) | 45-60 days |
| Permit Fees | $4,000-$15,000 depending on size and type | $2,500-$4,000 |
| Impact Fees | Waived for units under 750 sq ft (state law) | $1,200-$2,000 |
| Pre-Approved Plans | Yes — LA has a Standard Plan Program with pre-appr | City offers expedited review for pre-approved plan |
Construction Costs
| Cost | Los Angeles, CA | Austin, TX |
|---|
| Avg Build Cost | $150,000-$350,000 | $125,000-$250,000 |
| Cost Per Sq Ft | $200-$400 | $165-$330 |
| Garage Conversion | $80,000-$180,000 | $60,000-$140,000 |
| Prefab ADU | $100,000-$250,000 | $85,000-$200,000 |
Rental Income Potential
| Rental | Los Angeles, CA | Austin, TX |
|---|
| 1BR Avg Rent | $1,800-$2,500/mo | $1,300-$1,900/mo |
| 2BR Avg Rent | $2,200-$3,200/mo | $1,700-$2,500/mo |
| Short-Term Rentals | Restricted — STR rules apply; host must be primary resident | Check local restrictions |
| Est. ROI | 6-10% annual return | 7-10% annual return |
Which City Is Better for ADUs?
Los Angeles scores 9/10 while Austin scores 8/10 on our ADU-friendliness index.
Los Angeles edges ahead overall. Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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