Stormwater Management: Altadena vs Pomona
How do stormwater management rules compare between Altadena, CA and Pomona, CA?
Altadena and Pomona have similar restriction levels.
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 →Pomona, CA
Los Angeles County
Pomona enforces stormwater management under the LA County MS4 permit and NPDES requirements. Construction projects must implement BMPs. The city participates in the San Gabriel River watershed programs.
View full Pomona rules →Key Facts Comparison
| Fact | Altadena | Pomona |
|---|---|---|
| Authority | LA County Code Title 12 + State Water Board MS4 | LA Regional Water Quality Control Board |
| Construction SWPPP | Required ≥1 acre disturbance | - |
| Illicit Discharge Hotline | (888) CLEAN-LA | - |
| Permit | - | LA County MS4 / NPDES |
| BMPs | - | Required for construction projects |
| Watershed | - | San Gabriel River |
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.
Pomona 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 Pomona public works.
Compare other topics
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