Stormwater is an engineering responsibility, and it is regulated by the Federal and State governments. Storm drains and the regional flood control system are a vast network of inlets, pipes, channels, basins, bridges, and support facilities that are maintained by the City, the County, and the US Army Corps of Engineers.

Follow the stormwater do’s and don’ts to help us maintain a clear and clean system.

The City of San Gabriel is in a non-flood hazard area. The City is covered by an NPDES (National Pollutant Discharge Elimination System) Permit issued by the State, and a new permit is expected to be issued in the next twenty four months. All new development projects in the City must comply with the NPDES Permit, and in some cases, with the Standard Urban Stormwater Mitigation Plan (SUSMP).

Street sweeping is a major effort by the City to keep it in compliance with NPDES. Over the next several years, the City will be working on preparing a stormwater master plan to inventory, analyze, and improve stormwater quality, drainage, and flood control in the City.

Storm Drains & Flood Control

The Public Works Department maintains all catch basins and storm drains that are not under the jurisdiction of LACDPW. Alhambra Wash, Rubio Wash, and Eaton Wash are flood control facilities which run through / along the City limits. 

Flood Zone Information

The city of San Gabriel is in flood zone C, non-flood hazard area. A panel map is not available.
  • Community number = 065055
  • Program Date = 23 Nov 1973
Requests for additional information should be directed to FEMA (under Federal Government pages of the phone book). Small portions of the City fall in a mapped area east of SG Blvd. and north of Las Tunas, but they are also designated non-flood zones.

Regional Water Quality Control Board

San Gabriel is served by the Los Angeles Regional Water Quality Control Board. The Board is also responsible for NPDES compliance and permitting, groundwater contamination, leaking underground storage tanks, and protection of surface water and ground water in the Los Angeles Basin.

Stormwater Permit 

The City must comply with the Clean Water Act, the National Pollution Discharge Elimination System and the MS4 Permit (issued by the Los Angeles Regional Water Quality Control Board). See ordinance 511 of SGMC.

At a minimum, projects are required to be sandbagged (minimum two bags high) to prevent run-off into the public right of way. Additional BMPs may be needed depending on the size and extent of development.

Street Sweeping Services

Street sweeping is conducted in the City by a contract vendor. Days when streets are swept vary. Check the current Street Sweeping Map for details.

Commercial / Business District streets are swept twice a week. Residential streets are swept once a week.

Street sweeping is a major best management practice utilized by the City to reduce pollution in stormwater. For questions or additional information on street sweeping, call the Public Works Department at (626) 308-2825.


The City uses the Los Angeles County Department of Public Works (LACDPW) Hydrology Manual for projects. Hydrology and Drainage Studies must be prepared by a registered civil engineer. The LACDPW Small Area Method may be used on projects in the city one acre in size or less.

The County Department of Public Works is located at 900 South Fremont Avenue in Alhambra. Its phone number is (626) 458-5100. LACDPW administers the Los Angeles County Flood Control District (LACFCD).

Permits from Other Agencies for Drainage Projects

Drainage projects may affect facilities under the control of another agency. Some examples are:
  • Interstate 10 (San Bernardino Freeway) under the jurisdiction of CALTRANS District 7
  • Flood control facilities under the jurisdiction of the Los Angeles County Flood Control District (Los Angeles County Department of Public Works)
  • Alhambra Wash under the jurisdiction of the U.S. Army Corps of Engineers (contact Ted Masigat of the Corps LA Office at (213) 452-3393)
  • County trunk sewers under the jurisdiction of the County Sanitation District

Additional Information

Find additional information here about Stormwater:
  • Know the Flow! - Do you know where Los Angeles gets its water? Click here to watch.
  • Clean and Blue -  LA County Department of Beaches & Harbors. Click here to watch.