Rayne of the Valley specializes in treating water just before it reaches the location our client will be using it, be it their home or business. But the water our customers use usually has to travel a long way before we can get to work on improving it for final use. According to the Los Angeles County Waterworks District, there are three main sources of water for its customers: local groundwater, water imported through the State Water Project (SWP) and the Colorado River Aqueduct (CRA). With this post, we’ll begin to outline these various sources that are so important for Los Angeles County, and the City of L.A. in particular. We’ll dedicate a future blog post to the Los Angeles Aqueduct, which is a topic unto itself.


Among the jewels of the LA County water system are our network of State Water Project reservoirs, which store water from previous wet years for use when water supplies are lower than usual. With the exception of several smaller reservoirs, the following are among the most significant reservoirs for public water use in Los Angeles County are:

  • Hollywood Reservoir (LADWP) serves Downtown LA and South LA
  • Griffith Park Headworks Reservoir Project (LADWP, 2015) a new project to replace the recently closed Silverlake and Ivanhoe Reservoirs that also supply the City of LA
  • Bouquet Reservoir (LADWP) located near Santa Clarita
  • Castaic Lake (Castaic Lake Water Agency) serves northern LA County
  • Morris Reservoir (LACDPW) located in Angeles Forest
  • Pacoima Dam (LACDPW) Sylmar
  • Lake Palmdale (State Water Project) provides water for Antelope Valley
  • Puddingstone Reservoir located in San Dimas
  • Pyramid Lake in Angeles Forest
  • San Gabriel Dam (LACFCD) provides groundwater recharge
  • Stone Canyon Reservoir (LADWP) provides water for West Los Angeles


Although many Angeleños believe that aqueducts or reservoirs provide their water, the reality is that even that largest community water systems (water delivery systems that serve more than one location) rely on local groundwater to some extent. According to the UCLA Luskin Center For Innovation’s 2015 LA County Community Water System Atlas and Policy Guide (you can download the PDF thru the link at the bottom of this post), of nearly 450 community water systems, 79 rely entirely on groundwater for supplying their customers. Groundwater wells are scattered throughout Los Angeles County, with many concentrated in areas like the south and northeast San Fernando Valley, the Beach Communities from El Segundo down south to Manhattan Beach, and southeast Los Angeles, including neighborhoods like Huntington Park, South Gate, Downey, Compton, and Lakewood. The danger with groundwater is in contamination that has occurred over time to the various groundwater sources in the region. To clarify the danger, the Luskin Center’s report further states that, among the 200+ water systems that rely on groundwater that is even somewhat contaminated, 85 of them have to deal with contamination from between 1-25% of their wells, while 33 of them have contamination in 51-100% of their wells.

Colorado River Aqueduct

Last but not least is the Colorado Aqueduct. Stretching nearly 250 miles from Lake Havasu in Arizona, across the Mojave and Colorado deserts, and ending on the eastern side of the Santa Ana Mountains, the Colorado River Aqueduct (CRA) delivers a maximum of 1,600 cubic feet per second of water from its namesake river to provide for the multitude of residents in Los Angeles County member cities, as well as diverting some water down to San Diego County. The support infrastructure for the CRA includes two reservoirs, five pumping stations to maintain flow, and over ninety miles of tunnels.

Combined, these three sources provide for a great majority of the water used by Los Angeles County residents. Without them, the region would simply not be able to sustain Greater Los Angeles metropolis that has arisen in the decades since these sources were first tapped.

To schedule a free consultation with a Rayne of the Valley water treatment professional on how easy it is to soften your water, and for a free, basic, no obligation water hardness test, visit www.raynedrops.com or call us toll-free: 800.594.3300