Who Do We Serve?

West Valley Water District serves approximately 83,218 customers with 21,049 active service connections in the communities of Bloomington, Colton, Fontana, Rialto, parts of unincorporated areas in San Bernardino, and a portion of Jurupa Valley in Riverside County.


Where Is Our Water From?

West Valley Water District obtains water from both local and imported sources to serve its customers and routinely tests for contaminants from these sources in accordance with Federal and State Regulations.

Local Water


51% - Over half of the District’s water supply is from its own groundwater wells, located in five local basins:

  • Chino Basin
  • Bunker Hill Basin
  • Lytle Creek Basin
  • North Riverside Basin
  • Rialto-Colton Basin

17% -Additional groundwater is purchased from San Bernardino Valley Municipal Water District through the Base Line Feeder Project. This water also comes from local wells in the Bunker Hill Basin. 

Surface Water

18% - The District obtains a portion of its surface water from Lytle Creek in the San Bernardino Mountains. This water is treated through the District’s Oliver P. Roemer Water Filtration Facility.


State Water Project

14% - The District also purchases surface water from the State Water Project through San Bernardino Valley Municipal Water District. This water is also treated through the District’s Oliver P. Roemer Water Filtration Facility.


How Often Is Our Water Tested?

Our water quality staff collects water quality samples on a weekly, monthly, quarterly, annual and triennial basis complying with the regulatory limits set by United States Environmental Protection Agency (EPA) and California Water Resources Control Board – Division of Drinking Water (DDW). We test for over 150 regulated and unregulated contaminants to ensure strict standards of water quality.


How Safe Is Our Water?

West Valley Water District vigilantly safeguards its water supplies. Our water meets all Federal and State Regulations. We are proud that the District not only meets but exceeds these standards.

EPA and DDW identify contaminants to regulate in drinking water to protect public health. These Agencies set regulatory limits for the amounts of certain contaminants in water provided by the public water systems. These contaminant standards are required by the Safe Drinking Water Act.

Contaminants are measured in milligrams per liter (mg/L), micrograms per liter (µg/L), and nanograms per liter (ng/L). Concentrations are expressed in this manner so that consistent comparisons can be made among the many contaminants that undergo testing. 

  • One milligram per liter (mg/L) is equivalent to one part per million.  To help put these numbers in context, one part per million is like 1 penny out of $10,000.
  • One microgram per liter (µg/L) is equivalent to one part per billion. 1 penny of $10,000,000.
  • One nanograms per liter (ng/L) is equivalent to one part per trillion. 1 penny of $10,000,000,000.

What Is The District Doing To Protect Our Water?

We are committed to improving water quality through innovative technologies. The District operates and maintains several treatment plants to ensure we deliver clean and safe water to our consumers:

  • The Groundwater Wellhead Treatment System, a new, first-in-the-nation project, using ground-breaking, cost-effective technology called bioremediation, was approved to remove perchlorate from drinking water supplies. The Groundwater Wellhead Treatment System utilizes Fluidized Bed Biological Reactors (FBRs) to remove perchlorate and nitrate from District Well No. 11 and Rialto Well No. 6. This treatment facility using FBR technology began delivering clean water to our customers in September 2016. The new treatment system that uses Fixed Bed Reactors (FXBs) for perchlorate, nitrate, and trichloroethylene removal will start delivering clean water to our customers in 2018.

  • The Oliver P. Roemer Water Filtration Facility treats surface water from Lytle Creek and State Project Water delivered through Lake Silverwood.

  • The Arsenic Removal Ion Exchange Treatment Plant treats water from Well No. 2.

  • Three Perchlorate Removal Ion Exchange Treatment Systems treat water from Well Nos. 16, 17, 18A, and 42.


What Contaminants Are Being Tested? 

West Valley Water District tests according to Title 22 of the California Code of Regulations, Safe Drinking Water Act. Click here to read Title 22

The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally-occurring minerals and in some cases, radioactive material can pick up substances resulting from the presence of animals or from human activity. Contaminants that may be present in source water include:

  • Microbial contaminants, such as viruses and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.

  • Inorganic contaminants, such as salts and metals, that can be naturally-occurring or result from urban storm water runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming.

  • Pesticides and herbicides that may come from a variety of sources such as agriculture, urban storm water runoff, and residential uses.

  • Organic chemical contaminants, including synthetic and volatile organic chemicals that are by-products of industrial processes and petroleum production, and can also come from gas stations, urban storm water runoff, agricultural application, and septic systems.

  • Radioactive contaminants that can be naturally-occurring or be the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (USEPA) and the State Water Resources Control Board (State Board) prescribe regulations that limit the amount of certain contaminants in water provided by public water systems.


Who is most vulnerable to contaminants in drinking water?

Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons; such as, persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. USEPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (1-800-426-4791).


Where can I get more information about water contaminants?

Drinking water may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the USEPA’s Safe Drinking Water Hotline (1-800-426-4791). You may also view the websites below for more information.



To view completed source water assessments, you may visit our District office located at: 855 W Base Line, Rialto, California, 92376 or call (909) 875-1804.