SW

Stormwater Directory

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Los Angeles County (Unincorporated)(3 more)

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Field
Local
Los Angeles County (Unincorporated)
Los Angeles County Department of Public Works
Permit
Permit / AuthorizationGrading Permit with LID Standards Compliance
Submit ToLos Angeles County Department of Public Works
Lead TimePlan review 4–8 weeks; LID compliance reviewed as part of grading/building permit
Application MethodOnline via LA County Department of Public Works; LID plan submitted with permit package
FeeGrading permit fees based on earthwork volume; LID plan review included
Water Quality
Impervious Cover LimitNo countywide cap; projects creating ≥ 500 sq ft of new or replaced impervious surface in unincorporated areas trigger LID requirements (one of the lowest thresholds in CA)
On-Site Treatment RequiredYes
Detention RequiredYes — Retain the 85th-percentile 24-hour storm on-site; if infeasible, biofiltration of 1.5× the design volume. County's LID Standards Manual governs sizing and selection.
Turbidity / Discharge StandardMust comply with state CGP and LA County MS4 Permit (Order R4-2012-0175 as amended) receiving water limitations
SWPPP
SWPPP / Local Plan RequiredYes — Erosion and Sediment Control Plan (construction); LID Plan / Standard Urban Stormwater Mitigation Plan (post-construction)
PE Stamp RequiredYes
Inspections
Inspection RequirementsCounty inspects grading and erosion control during construction. Post-construction LID facilities require recorded covenants and maintenance agreements. Annual self-inspection and periodic county verification.
Inspector QualificationQSP/QSD per state CGP; no additional county certification
Design & Zones
Local Design ManualLA County LID Standards Manual
Special Overlay ZonesSignificant Ecological Area (SEA), Hillside Management Area, Santa Monica Bay Watershed