City of Riverside
City of Riverside Public Works Department / Community and Economic Development Department
CityMS4 Phase IVerified 2026-03
Local Permit / Authorization
- Permit Required
- Yes
- Permit Name
- Grading Permit with Water Quality Management Plan (WQMP)
- Submit To
- City of Riverside Public Works Department / Community and Economic Development Department
- Lead Time
- Plan review 4–6 weeks; WQMP reviewed concurrently with grading/building permit
- Application Method
- Online or in-person via City of Riverside permit center; WQMP submitted as part of permit application
- Fee
- Grading permit fees per project scope; WQMP review fee included
Water Quality Standards
- Impervious Cover Limit
- No citywide cap; projects creating ≥ 5,000 sq ft of new impervious surface require a project-specific WQMP
- On-Site Treatment Required
- Yes
- Detention Required
- Yes
- Detention Standard
- Retain the 85th-percentile 24-hour storm event using LID BMPs; infiltration preferred in areas with suitable soils; bioretention or proprietary treatment accepted elsewhere
- Turbidity Standard
- Must comply with state CGP and Santa Ana Regional Water Board Basin Plan objectives
Local SWPPP / Drainage Plan
- Local Plan Required
- Yes
- Plan Name
- Project-specific Water Quality Management Plan (WQMP) for post-construction; SWPPP per state CGP for construction
- PE Stamp Required
- Yes
WQMP must be prepared by a registered Civil Engineer. Riverside implements the Riverside County MS4 Permit (Order R8-2010-0033) issued by the Santa Ana Regional Water Board.
Local Inspection Requirements
- Requirements
- City conducts grading inspections and BMP installation verification. Post-construction BMPs require recorded maintenance agreements with annual self-inspection.
- Inspector Qualification
- QSP/QSD per state CGP; no additional city certification
Special Overlay Zones
Santa Ana River Watershed
Trigger: Properties draining to Santa Ana River and tributaries
Restriction: Subject to TMDL requirements for bacteria, nutrients, and metals; enhanced treatment BMPs may be required
Hillside / Steep Slope Overlay
Trigger: Properties with slopes ≥ 15%
Restriction: Enhanced erosion control; reduced grading; slope stabilization plan required; revegetation of disturbed slopes mandatory
Design Manual
- Manual Name
- Riverside County WQMP Guidance / Santa Ana Region BMP Design Manual
Official Resources
Jurisdiction Notes
Riverside operates under the Riverside County MS4 Permit in the Santa Ana Region. The WQMP framework is the primary mechanism for ensuring post-construction water quality compliance. The city's semi-arid climate and varied terrain create different BMP feasibility across the city.
Remember: These local requirements are in addition to the SWRCB state construction permit. Both must be satisfied before breaking ground.
Disclaimer: This information is provided for general reference only. Always verify requirements directly with City of Riverside Public Works Department / Community and Economic Development Department and the agency website before beginning construction.