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Turlock's drinking water quality outlined in annual report
water faucet
A complete list of the contaminants detected in Turlock’s drinking water during 2020 can be found in the annual report, available at:

The City of Turlock had one drinking water violation in 2020, according to the annual drinking water quality report recently released by the City.

As part of the Safe Drinking Water Act, the Environmental Protection Agency (EPA) requires community water systems to deliver a Consumer Confidence Report, also known as an annual drinking water quality report, to their customers. These reports provide information about local drinking water quality, data from tests conducted the previous year, and contact information for any questions or concerns.

The City of Turlock Municipal Services Department published its annual drinking water quality report on July 1.

Trichloropropane, an industrial solvent that has been found as an impurity in soil fumigants and persists in groundwater, was the only contaminant found in enough amounts to cause the City of Turlock to earn a violation, according to the report. This is an ongoing issue for the City. In 2019, five City wells were tested above the maximum allowable level of trichloropropane.

City staff tests water at various points in the distribution system for bacteria and a wide range of inorganic and organic chemicals. The City tests drinking water for more chemicals and more frequently than required by law.

Currently, the City of Turlock gets 100% of its drinking water supply from well water. For the past 30 years, the City has been working on securing an alternate source of water — treated surface water from the Tuolumne River. In 2011, the Cities of Turlock and Ceres, as members of the Stanislaus Regional Water Authority (SRWA), started the process of building a plant to deliver treated Tuolumne River water to homes.

Both Ceres and Turlock will blend the new source of water with treated groundwater. Turlock will receive up to 10 mgd while Ceres has a claim of 5 mgd. Project completion and operations are expected to begin as soon as June 2023.

Groundwater contamination is a problem throughout the state. In April, the state launched a program to help those impacted by nitrate-laden wells.

The Central Valley Regional Water Quality Control Board is providing bottled water deliveries or bottle-filling kiosks to six geographic zones deemed to have the most-serious groundwater contamination issues. 

The Turlock Subbasin has been identified as a Priority 1 zone by the board and is one of the two largest zones included in the program. The Valley Water Collaborative established the Turlock Management Zone to achieve three nitrate management goals as part of the Board’s Nitrate Control Program: ensuring a safe drinking water supply, reducing nitrate loading and implementing long-term, managed restoration of impaired water bodies.

Nitrate in drinking water can lead to serious health outcomes, especially for infants and pregnant women. It is considered a risk to human health when it is above 10 parts per million (ppm) of nitrate nitrogen, which is the primary maximum contaminant level (MCL), also known as the nitrate drinking water standard.

Via an interactive map on the VWC’s website (, it’s clear that many areas in Turlock which utilize wells are above 10 ppm. 

A complete list of the contaminants detected in Turlock’s drinking water during 2020 can be found in the annual report, available at:

For questions about the annual drinking water quality report, or to request that a paper copy be mailed to you, contact the Municipal Services Department at or (209) 668-5590.