Stormwater Management: Downey vs Los Angeles
How do stormwater management rules compare between Downey, CA and Los Angeles, CA?
Downey has fewer restrictions than Los Angeles.
Downey, CA
Los Angeles County
Downey is subject to LA County MS4 NPDES permit requirements for stormwater management. New development and significant redevelopment must implement Best Management Practices (BMPs) for stormwater quality.
View full Downey 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 | Downey | Los Angeles |
|---|---|---|
| Permit | LA County MS4 NPDES | - |
| New Development | BMPs required | - |
| Reporting | Illicit discharge reporting to city | - |
| Enforcement | Public Works Department | - |
| 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.
Downey 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 Downey public works.
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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