Lot Coverage Limits: Altadena vs El Monte
How do lot coverage limits rules compare between Altadena, CA and El Monte, CA?
Altadena and El Monte 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 →El Monte, CA
Los Angeles County
El Monte zoning code establishes maximum lot coverage per zone. Architectural features like cornices, chimneys, canopies, and bay windows that do not provide additional floor space may extend into required setback areas.
View full El Monte rules →Key Facts Comparison
| Fact | Altadena | El Monte |
|---|---|---|
| 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 | - |
| Coverage | - | Per zone maximum |
| Exceptions | - | Architectural features may extend |
| ADU | - | Included in lot coverage calc |
| Code | - | Title 17 development standards |
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.
El Monte 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 El Monte zoning for your district’s maximum.
Compare other topics
See how Altadena and El Monte compare on other ordinance categories.
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