Setback Rules: Altadena vs Downey
How do setback rules rules compare between Altadena, CA and Downey, CA?
Altadena and Downey have similar restriction levels.
Altadena, CA
Los Angeles County
Altadena R-1 setbacks: front = smallest existing front yard on the same block (min 20 ft); rear = 35 ft (lots ≥20,000 sf) or 25 ft (lots <20,000 sf); side = 10% of avg lot width, min 5 ft interior / 10 ft reverse corner.
View full Altadena rules →Downey, CA
Los Angeles County
Downey building setbacks vary by zone. ADUs require 4 ft side/rear setbacks. Front setbacks established by Planning Commission where necessary. No building may encroach into required yards without approval.
View full Downey rules →Key Facts Comparison
| Fact | Altadena | Downey |
|---|---|---|
| Code Section | Altadena CSD 22.306.070.A.1 | - |
| Front (min) | 20 ft (or block average) | - |
| Rear ≥20k sf | 35 ft | - |
| Rear <20k sf | 25 ft | - |
| Side Interior | 10% avg lot width, min 5 ft | - |
| Within 15 ft of PL | Max 23 ft tall | - |
| ADU Setback | - | 4 ft side and rear |
| Front Yard | - | Set by zone/Commission |
| Encroachment | - | Not allowed without approval |
| Nonconforming | - | Additions must conform |
Highlighted rows indicate differences between cities.
Altadena FAQ
What's the front yard setback in Altadena?
Match the smallest existing front yard on the same side of the block, but at least 20 feet — Altadena CSD 22.306.070.A.1.b.
Downey FAQ
How do I find my setback requirements?
Check Downey zoning map for your parcel’s zoning district, then consult the zoning code for that district’s setbacks.
Can I build closer than the setback?
Only with a variance approved by the zoning board or if your structure qualifies for an exception.
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