Cypress Water Production Facility

The City’s Cypress Water Production Facility (CWPF) was constructed to reduce reliance on costly imported water. Imported water purchased from West Basin Municipal Water District (WBMWD) costs the city roughly double the cost of treated groundwater. CWPF consists of three main components:

  1. the city’s single groundwater well, Well No. 5
  2. treatment plant facilities
  3. the Cypress Street Reservoir.

CWPF is the main source of water supplied to the portion of the city located north of Pacific Coast Highway, and accounts for approximately 2/3 of the typical total demand for water in our community.

CWPF treats Well No. 5 groundwater for iron, manganese, and color. The treatment process consists of (shown below):

  • oxidation and precipitation with a mix oxidant solution
  • filtration of the precipitates through a manganese greensand and anthracite pressure filter
  • chloramine disinfection to kill the remaining microorganisms
  • an ortho/polyphosphate injection to inhibit calcium hardness and minimize corrosion

At CWPF, imported surface water purchased from WBMWD and treated groundwater from Well No. 5 are blended together. The blended water is monitored to ensure both primary and secondary water quality standards are met, and the blended water supply provides improved water reliability while reducing the cost of water to ratepayers in the City. The mix of groundwater and imported water changes throughout the year as imported water prices fluctuate.

Water generated at the CWPF comes from groundwater supplies that are a part of the West Coast Basin. As a result, the water that comes from the groundwater supply can sometimes have a different flavor or odor than the imported water. Groundwater treated at the CWPF must adhere to the same Federal and State water quality requirements as the imported water it is mixed with.

Lomita Water treats groundwater at the CWPF through the following processes:

  • Sodium hypochlorite dosing system to oxidize iron and manganese, and to produce chloramines for disinfection
  • A pressurized greensand filter system to remove iron and manganese
  • Aqua ammonia storage and dosing system to form chloramines for disinfection
  • Ortho-polyphosphate storage and dosing system for corrosion control
  • Cascade aeration system within the reservoir to promote circulation

To ensure ongoing operation of CWPF during a power outage, a 300 kilowatt (kW) standby emergency generator is located onsite at the facility, and is tested weekly.

The Metropolitan Water District of Southern California (MWD) is a consortium of 26 cities and water districts that provides drinking water to nearly 19 million people in Southern California, including West Basin Municipal Water District (WBMWD) from whom the City purchases treated water. MWD supplies the City with water treated at the F.E. Weymouth Treatment Plant. Most of the water treated at this plant travels down the Colorado River and flows through MWD’s 242-mile Colorado River Aqueduct. Some MWD water also comes from Northern California rivers and streams that feed the State Water Project’s 444-mile California Aqueduct.

The Weymouth plant uses conventional techniques to treat your water. This includes the coagulation process where aluminum sulfate and other chemical additives cling to particles in the water, forming large particles that settle to the bottom of large sedimentation basins. Then, the water flows through coal and sand for filtration. Chloramine (chlorine plus ammonia) disinfection is used to kill remaining microorganisms, such as bacteria, and to keep the water safe as it travels to your tap.

The Water Replenishment District of Southern California (WRD) manages groundwater for nearly 4 million residents in 43 cities of Southern Los Angeles County. There is one groundwater source well within the City, Well No. 5, with an approximate production capability of 1,500 gallons per minute (GPM). The City has adjudicated rights to 1,352 acre-feet of groundwater, annually. One acre-foot is enough water to cover an entire football field about one foot deep, and provides the annual water needs for two average sized households.