248 E. Foothill Blvd., Suite 200, Monrovia, CA, 91016

Local Water

Local Water 

Aside from local groundwater courtesy of the snow melt from the San Gabriel Mountains and the rain that flows through the San Gabriel River, water recycling and watershed protection are key efforts in helping the groundwater basins meet local demands. Upper District works with several agencies that operate and manage the water infrastructure along the San Gabriel River Watershed and the Main San Gabriel Basin.


Baldwin Park Key Well

The Baldwin Park Key Well is located in the central portion of the San Gabriel Valley within the City of Baldwin Park and is used as a general indication of water elevations throughout the Main San Gabriel Basin. The Main San Gabriel Basin Watermaster (Watermaster) is the key agency responsible for administering water rights and the management and protection of groundwater resources.

Where does your local water come from?

Every time you turn on the faucet, you are tapping into a complex water delivery system. We have one basin that supplies water for the entire San Gabriel Valley. For 60 years, Upper District has educated residents about our local water supply in the San Gabriel Valley and the importance of protecting this most precious resource to ensure the long-term sustainability of the Main San Gabriel Basin.

Upper District will take you on that journey of discovery. Watch the video to learn more!

Main San Gabriel Basin

The groundwater basin is more valuable than one may think. The basin holds rainfall, snowmelt, conserved water, and imported water, providing most of our water when needed. The freshwater storage capacity of the groundwater basin is estimated to be about 8.6 million-acre feet. To put into context, one-acre foot of water is equivalent to an entire football field covered in 1 foot of water.

San Gabriel River Watershed

Upper District works closely with Los Angeles County Flood Control District which captures over 95% of all precipitation that falls on average within the San Gabriel River Watershed to recharge the groundwater basin. They do this through the help of two important dams and a vast infrastructure for groundwater replenishment.

There are five major dams along the San Gabriel River, moving downstream from the San Gabriel Mountains. These dams are Cogswell Dam, San Gabriel Dam, Morris Dam, Santa Fe Dam and Whittier Narrows Dam.

San Gabriel Dam

San Gabriel Dam is an earth fill dam on the San Gabriel River in the San Gabriel Mountains within the National Angeles Forest. This 291-feet high and 1,500 feet long dam was constructed in 1939 and primarily serves as a water supply source, flood control, water conservation and hydroelectric power.

Morris Dam

Built in 1934 by the City of Pasadena, Morris Dam is used for flood control and flow regulation for groundwater recharge. The gravity dam is 245 feet high and 800 feet long and crosses the San Gabriel River. Both San Gabriel and Morris Dams are owned and operated by the Los Angeles County Flood Control District.

Santa Fe Spreading Grounds

The Santa Fe Spreading Grounds are operated and maintained by the Los Angeles County Flood Control District. The spreading grounds are designed to control flooding and conserve water through storm water capture. Water percolates into the groundwater basin through the spreading grounds. These are located near the 210-605 freeway interchange.