Valley Generating Station


On August 26, 2020, South Coast AQMD learned of an ongoing methane leak occurring at the Los Angeles Department of Water and Power (LADWP) Valley Generating Station located in Sun Valley. South Coast AQMD had not received any prior public complaints concerning odors from the facility, nor were any leaks reported.

Ongoing Investigation

An inspector was dispatched to the site that evening and used a FLIR optical gas imaging camera and handheld toxic vapor analyzer (TVA) to identify leaks consistent with what was reported by LADWP.

A team of inspectors were sent to the site again on August 27th and September 2nd and identified additional leaks at the facility. A Notice to Comply was issued to LADWP requesting maintenance records, data, and other information.

This facility operates under South Coast AQMD’s Title V and RECLAIM programs and is subject to annual onsite inspections.  Although South Coast AQMD does not regulate methane emissions, it is currently evaluating next steps including potential enforcement actions.  

LADWP currently has an emissions monitoring system in place at the facility. South Coast AQMD is working with LADWP to provide technical support on an additional air monitoring system to detect for methane.

Methane is regulated by the California Air Resources Board (CARB) and South Coast AQMD is coordinating with CARB on future actions and will update this page with further information as it becomes available.

Mobile Platform Air Measurement Results

In addition to an inspection team, South Coast AQMD deployed its mobile monitoring platform to evaluate methane levels in and around the perimeter of the facility and in the community. Results from those measurements showed methane levels to be within typical background levels.

In addition, four air samples were collected on site and upwind. These were analyzed for methane and volatile organic compounds (VOCs). Results of samples taken onsite show elevated levels of methane. No elevated levels of toxic VOCs were observed. The upwind sample results show methane and other VOCs within typical levels.

View Lab Reports (PDF) 

VGS Monitoring Map 8-27

Map showing measurements near the LADWP Valley Generating Station. Elevated levels are results from samples taken on site. (August 27, 8:30am-12pm)


South Coast AQMD continues to encourage the public to call our complaint line at 1-800-CUT-SMOG (800-288-7664) or use the on-line complaint system to report odors, dust, or any other outdoor air quality concern. The agency continues to attempt to respond to each complaint received. More guidance and helpful tips when calling the complaint line can be found at:

Newsletter Sign Up
Periodic newsletter updates via Email on a variety of air quality-related topics

South Coast Air Quality Management District

21865 Copley Dr, Diamond Bar, CA 91765



© 2020 South Coast Air Quality Management District