Lot Coverage Limits: Altadena vs Norwalk
How do lot coverage limits rules compare between Altadena, CA and Norwalk, CA?
Altadena and Norwalk have similar restriction levels.
Altadena, CA
Los Angeles County
Altadena R-1 max Gross Structural Area (GSA) and lot coverage = (0.25 × net lot area) + 1,000 sq ft, never exceeding 9,000 sq ft total (Altadena CSD 22.306.070.A.4).
View full Altadena rules →Norwalk, CA
Los Angeles County
Norwalk limits the percentage of a lot that can be covered by impervious surfaces and structures. Residential lots typically allow 40 to 60% coverage.
View full Norwalk rules →Key Facts Comparison
| Fact | Altadena | Norwalk |
|---|---|---|
| Code Section | Altadena CSD 22.306.070.A.4 | - |
| GSA Formula | 0.25 × lot area + 1,000 sf | - |
| Maximum Cap | 9,000 sq ft | - |
| Excluded From GSA | Cellars + auto garages/carports | - |
| Residential Limit | - | 40 to 60% typical |
| Includes | - | Buildings, driveways, patios |
| Permeable Pavers | - | May get partial credit |
| Topic | - | Lot Coverage |
Highlighted rows indicate differences between cities.
Altadena FAQ
How big a house can I build on a 10,000-sq-ft Altadena lot?
Maximum GSA = 0.25 × 10,000 + 1,000 = 3,500 sq ft (excluding garage and cellar). The absolute cap is 9,000 sq ft on any lot.
Norwalk FAQ
What counts as lot coverage?
All impervious surfaces: buildings, garages, driveways, patios, and walkways. Permeable pavers may be partially excluded.
How do I calculate my lot coverage?
Divide total impervious surface area by total lot area. Check Norwalk zoning for your district’s maximum.
Compare other topics
See how Altadena and Norwalk compare on other ordinance categories.
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