Stormwater Management: Altadena vs Los Angeles
How do stormwater management rules compare between Altadena, CA and Los Angeles, CA?
Altadena has fewer restrictions than Los Angeles.
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 →Los Angeles, CA
Los Angeles County
LAMC 64.72 (LID Ordinance, Ord. 183833) requires new development to manage stormwater runoff on-site through infiltration, bioretention, or capture systems. Priority projects must meet MS4 permit standards using the Development BMP Handbook. Projects disturbing 1+ acres need a state SWPPP. Grading permits are conditioned on stormwater compliance and a recorded covenant.
View full Los Angeles rules →Key Facts Comparison
| Fact | Altadena | Los Angeles |
|---|---|---|
| Authority | LA County Code Title 12 + State Water Board MS4 | - |
| Construction SWPPP | Required ≥1 acre disturbance | - |
| Illicit Discharge Hotline | (888) CLEAN-LA | - |
| Code Section | - | LAMC 64.72 (LID Ordinance) |
| Requirement | - | On-site stormwater management |
| Hierarchy | - | Infiltration > bioretention > treatment |
| 1+ Acre Sites | - | State SWPPP required |
| Covenant | - | Recorded BMP maintenance agreement |
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.
Los Angeles 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 Los Angeles public works.
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