Three years after the Central Valley Regional Water Quality Control Board launched a novel program that has brought replacement drinking water to more than 1,200 households with nitrate-impacted wells in designated areas of the Central Valley, the regional board is expanding the program to new areas in eight groundwater basins.

The Central Valley Water Board recently mailed 938 Notices to Comply to permit holders in these areas, known as Priority 2 management zones within its Salinity Alternatives for Long-Term Sustainability (CV-SALTS) program.

Collectively, these notices affect dischargers – growers, dairies, industrial facilities and wastewater plants – in the following basins: Delta-Mendota, Eastern San Joaquin, Madera, Merced, Kern County (Poso), Kern County (West-side South), Tulare Lake and Yolo.

These entities are now required to begin testing potentially impacted domestic wells and to provide free replacement drinking water where nitrates are found to exceed health standards. Residents in these management zones whose wells are potentially impacted by nitrate contamination can expect to be contacted in early 2025 about free well testing.

If their wells test above minimum contaminant levels, they will qualify to receive free replacement drinking water. Households that have received replacement drinking water so far during the first phase of the program are in Priority 1 management zones in the Modesto, Turlock, Chowchilla, Kings, Kaweah and Tule groundwater basins.

“The CV-SALTS program is a great example of how innovation and collaboration can meaningfully address the growing threat of nitrates and salinity in our groundwater and improve people’s lives in the Central Valley,” said Patrick Pulupa, executive officer for the Central Valley board. “Our experience with dischargers during the first phase of the program has been positive. As we embark on the program’s second phase, we look forward to collaborating with dischargers in Priority 2 zones to bring about access to safe drinking water for thousands more residents.”

Nitrate in drinking water can lead to serious health issues, 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.

For more information regarding the status of the CV-SALTS Nitrate Control Program, see the CV-SALTS website: www.cvsalinity.org.

The Central Valley Regional Water Board is a state agency responsible for managing water quality and protecting surface and groundwater beneficial uses such as aquatic habitat and human health for 11,350 miles of streams, 579,110 acres of lakes, and the largest contiguous groundwater basin in California. It is the largest of nine regional boards, encompassing 60,000 square miles, or about 40 percent of the state.

Thirty-eight of California’s 58 counties are either completely or partially within the regional board’s boundaries, formed by the crests of the Sierra Nevada on the east, the Coast Ranges and Klamath Mountains on the west, the Oregon border on the north, and the Tehachapi Mountains on the south.