Stormwater Management: Altadena vs Pasadena
How do stormwater management rules compare between Altadena, CA and Pasadena, CA?
Altadena has fewer restrictions than Pasadena.
Altadena, CA
Los Angeles County
LA County operates under a regional MS4 permit issued by the LA Regional Water Quality Control Board. LA County Code Title 12 prohibits discharging non-stormwater (sediment, chemicals, paint, sewage, washwater) into storm drains.
View full Altadena rules →Pasadena, CA
Los Angeles County
Pasadena's Stormwater Management and Discharge Control (PMC Chapter 8.70) prohibits illicit discharge to the municipal stormwater system. LID plans required for new development must retain the 85th percentile storm on-site. NPDES permit compliance mandatory.
View full Pasadena rules →Key Facts Comparison
| Fact | Altadena | Pasadena |
|---|---|---|
| Authority | LA County Code Title 12 + State Water Board MS4 | - |
| Construction SWPPP | Required ≥1 acre disturbance | - |
| Illicit Discharge Hotline | (888) CLEAN-LA | - |
| Code Section | - | PMC Chapter 8.70 |
| LID | - | Retain 85th percentile storm |
| NPDES | - | LA County MS4 permit |
| Design Volume | - | 1.0-1.2 inches per hour |
Highlighted rows indicate differences between cities.
Altadena FAQ
Can I hose my driveway into the gutter in Altadena?
Generally no — soapy or sediment-laden runoff into the storm drain violates the LA County NPDES MS4 permit and Title 12.
Pasadena FAQ
Do I need a stormwater plan for my project?
Generally required for new construction and major renovations that increase impervious surface area. Small residential projects may be exempt.
What is an illicit discharge?
Any non-stormwater substance entering the storm drain system, including paint, oil, chemicals, or sediment. Report violations to Pasadena public works.
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