Anaheim Water Sources

Where Does Our Water Come From?

Anaheim’s water supply is a blend of groundwater from our own wells and water imported from Northern California and the Colorado River by the Metropolitan Water District of Southern California (MWD). The source water for our wells is the Orange County Groundwater Basin that is replenished with water from the Santa Ana River, local runoff, imported water, and purified recycled water.

Imported Water

MWD's imported water supplies come from Northern California via the State Water Project (SWP) and from the Colorado River via Colorado River Aqueduct (CRA).  MWD treats the raw water obtained from these sources at the Robert B. Diemer Filtration Plant located north of Yorba Linda and delivers it to Anaheim and other cities in Orange County through five feeders.  Anaheim receives treated water from seven connections on MWD’s treated water feeders and one connection on a raw water feeder. Raw MWD water is delivered to Walnut Canyon Reservoir (WCR) and treated at Anaheim’s August F. Lenain Water Treatment Plant (Lenain) before entering the distribution system. The total available capacity is approximately 170 cubic feet per second (cfs).

Orange County Groundwater Basin

Managed by the Orange County Water District (OCWD), the groundwater basin is 350 square miles in area and lies beneath most of northern and central Orange County. Anaheim and more than 20 cities and retail water districts pump from the groundwater basin to provide water to homes and businesses. Your water source depends on where you live or work within the boundaries of our community. Generally, the source of water for areas east and south of the 57 and 91 freeway interchange is imported water. The central and western portions of Anaheim mostly receive groundwater or a blend with imported supplies. 

Groundwater Replenishment System

In an effort to create a more reliable and local resource, the City is participating in the Groundwater Replenishment System. 

The Groundwater Replenishment System (GWRS) was constructed as a joint project of OCWD and the Orange County Sanitation District to recycle wastewater and provide a drought-proof source of water for our region. 

The GWRS uses advanced treatment technologies to clean wastewater and then returns it to groundwater via recharge basins in Anaheim and direct injection near the coast. The water is further cleaned by layers of soil and rock, and ultimately refills local water aquifers over time. It is important to remember that GWRS water does not go directly into your drinking water. Instead, it goes into the ground, where it will be naturally filtered by thousands of feet of soil and it will remain in the ground for years before it reaches a drinking water well. 

You can find additional information on the GWRS by visiting the website or by calling OCWD directly at 714-378-3333.