CV-SALTS – Managing Salt and Nitrate in the California Central Valley

Safe Drinking Water

Providing safe drinking water in areas of the Central Valley where groundwater supplies do not meet safe standards for nitrate is the first priority for the new Nitrate Control Program.

Nitrate Control Program Goals

  • Provide safe drinking water supplies.

  • Reduce nitrate impacts to water supplies.

  • Restore groundwater quality, where reasonable and feasible.

The following information describes the causes, concerns, and solutions for nitrate in drinking water

girl drinking waterMany communities in the Central Valley rely on groundwater as their primary source of drinking water. In some localized areas, contaminants, including salts, nitrate, pesticides, heavy metals, and organisms that can cause disease, have seeped into the groundwater. Not having safe drinking water, whether from private wells or from a public water system, is an urgent problem, particularly in rural, low-income communities.

The California State Water Resources Control Board, Division of Drinking Water (DDW) regulates public drinking water systems.

According to the State Water Board, “Nitrite can interfere with the ability of red blood cells to carry oxygen to the tissues of the body, producing a condition called methemoglobinemia. It is of greatest concern in infants, whose immature stomach environment enables conversion of nitrate to nitrite, which is then absorbed into the blood stream. The effects of nitrite are often referred to as the ‘blue baby syndrome.’ High nitrate levels may also affect the oxygen-carrying ability of the blood of pregnant women.” The DDW web page offers a wide range of information about drinking water health and regulations.

Wastewater is water discharged from our home (sewer or septic tank), agriculture (farms and dairies), industries (such as food processing), or cities (public sewer system), and from surface or stormwater runoff. This wastewater carries contaminants (nitrate, pesticides, heavy metals, and organisms) that can be released into a river, a lake, or the soil where it seeps or moves slowly into the groundwater below the ground. At high enough concentrations, the contaminants can make groundwater supplies unusable for drinking water and, in some cases, for agricultural use.

In localized areas, nitrate is a major cause of unsafe drinking water. Nitrate seeps slowly into the groundwater from fertilizers or after being discharged as wastewater from animal feedlots, industrial facilities, municipal wastewater treatment plants, or leaky septic systems. For example, when fertilizer containing nitrate is applied to crops, not all nutrients in the fertilizer are absorbed by the plants. The excess nutrients then seep into groundwater supplies as nitrate. 

Drinking water with high levels of nitrate can create human health risks, especially for infants and pregnant women. Because nitrate levels have been increasing in groundwater over the last few decades, some drinking water supplies are unhealthy and do not meet State drinking water standards. 

Agricultural, municipal, and industrial facilities and households are all responsible for managing possible contaminants in their wastewater, or discharges of waste that enter our state’s waters. Authority for regulating discharges to waters of the state, which includes both surface and ground water, is provided primarily to the Central Valley Regional Water Quality Control Board (Central Valley Water Board), with oversight granted to the State Water Resources Control Board. For discharges to surface waters, the U.S. Environmental Protection Agency also has authority under the Clean Water Act. The U.S. EPA Clean Water Act authorities have been delegated to the State Water Board and the Central Valley Water Board.

Drinking water in the Central Valley is provided in several ways—large city systems, water districts, small community water systems, and private household wells. The State Water Board, Division of Drinking Water regulates small and large drinking water systems, but not individual wells. In areas where groundwater has high nitrate levels, the cost of treatment systems and maintenance can be high, particularly for small systems and private wells. In many small, disadvantaged communities, residents struggle to pay high water bills for treated water or the costs for bottled or tanked water. 

Current regulations for nitrate discharges do not provide a link between the discharge and the need for groundwater users to have safe drinking water. More effort is needed to provide safe drinking water in communities affected by nitrate in groundwater.

New nitrate regulations adopted in 2019 strengthen the requirements for providing safe drinking water for households whose water exceeds safe standards for nitrate. The new regulations were developed to achieve three goals:

  • Identify short- and long-term solutions to ensure safe drinking water in communities where groundwater is high in nitrates.
  • Reduce impacts from nitrate and salts to the groundwater.
  • Where reasonable and feasible, restore groundwater quality.

These new requirements are being implemented first in high-priority areas that include: Kaweah, Turlock, Chowchilla, Tule, Modesto, and Kings groundwater sub-basins and basins. Nitrate permittees in these areas are required to test household water supplies and provide drinking water where nitrate levels exceed safe standards. Management Zones have formed in these areas to provide the testing and drinking water and develop long-term solutions.

The State Water Resources Control Board (State Water Board) has programs that support access to safe drinking water supplies and help offset the cost of buying water. Depending on the program, the State Water Board offers technical and financial assistance (loans and/or grants) for smaller community water systems and residents located in disadvantaged communities.

  • Senate Bill 200, signed into law July 2019 provides $130 million annually for ten years to the State Water Board for grants, loans, contracts, or services to help water systems provide safe and affordable drinking water.
  • In 2016, funds (from the State’s Cleanup and Abatement Fund Account) were allocated for the Interim Emergency Drinking Water program to address drought-related drinking water emergencies and provide interim emergency drinking water to disadvantaged communities with a contaminated water supply.
  • The State Water Board Division of Financial Assistance Office of Sustainable Water Solutions offers funding and technical assistance to disadvantaged communities through three funds: The Drinking Water State Revolving Fund, Clean Water State Revolving Fund, and Proposition 1 bond funds.

The Central Valley Salinity Coalition partnered with Self-Help Enterprises to pilot a program to bring testing and safe drinking water to those that are most sensitive to nitrates through a partnership with the Women, Infants, and Children (WIC) program in the San Joaquin Valley.  The Pilot Report is available here with recommendations for expanding the program in other areas.