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Sacramento's Drinking Water

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The City's priority is water quality and safety. We accomplish this by meeting all state and federal drinking water standards, which are designed to protect public health. Our water goes through rigorous testing processes even greater than any bottled water treatment. Each day, we test our water hundreds of times to ensure that we continue to meet drinking water standards.

  • Our water goes through a strict testing process that meets or exceeds all federal and state water drinking standards.
  • We test our water hundreds of times per day to ensure that we continue to meet the standards (Maximum Contaminant Levels, or MCLs) as required by the state and federal government. The City also strives to meet Public Health Goals, which are set by the State of California to encourage drinking water providers to do the best they can to provide safe, high-quality drinking water. We actively work toward these goals and report progress to the City Council and the public every three years.

The City produces an annual Consumer Confidence Report (CCR) that includes the detection of contaminants in the water supply as well as disclosure on exceedances of the MCL in the prior year, if any.

See also a response to false assertions by ABC 10 about City’s drinking water.

Disinfection Byproducts

What are disinfection byproducts?

Disinfection byproducts (DBPs) form when disinfectants used to treat drinking water react with naturally occurring materials in the water (e.g., decomposing plant material). Total trihalomethanes (TTHM) and haloacetic acids (HAA5) are widely occurring classes of DBPs formed during disinfection with chlorine. The amount of TTHM and HAA5 in drinking water from one water system can change from day to day, depending on the season, water temperature, amount of chlorine added, the amount of plant material in the water, and a variety of other factors.

Why is drinking water disinfected?

Disinfecting tap water is critical to protect the public from disease-causing microorganisms. Chlorine is the most commonly used disinfectant. Drinking water is disinfected to kill bacteria, viruses, and other organisms that cause serious illnesses and deaths. Disinfection of drinking water has benefited public health enormously by lowering the rates of infectious diseases spread through untreated water.

What are the drinking water regulations for disinfection byproducts?

Regulations are established by the U.S. EPA.

Disinfection byproducts are monitored in accordance with the Environmental Protection Agency’s Stage 2 DBP Rule:

Sampling sites are monitored quarterly for TTHM and HAA5. For each monitoring site, the last four quarterly results for TTHM and HAA5 are averaged to calculate a Locational Running Annual Average (LRAA). In order to comply with the Stage 2 DBP rule, these LRAAs must not exceed the Maximum Contaminant Levels (MCL) established for TTHM and HAA5.

What is a Maximum Contaminant Level (MCL)? What are the MCLs for Total Trihalomethanes and Haloacetic Acids?

An MCL is the regulatory limit on the amount of a substance that is allowed in public water systems. The MCL for TTHM is 0.080 milligrams per liter (mg/L) or 80 parts per billion (ppb) for each LRAA. The MCL for HAA5 is 0.060 mg/L or 60 ppb for each LRAA. In other words, if the sampling site’s LRAA (the average of the last four quarterly sampling results for the site where the sample is taken) exceeds 80 ppb for TTHM or 60 ppb for HAA5, the MCL is exceeded. So long as the LRAA for a site remains at or below these regulatory levels, there is no exceedance of the MCL and the water is considered safe to drink.

How will I know if disinfection byproducts in my drinking water exceed the MCL?

Water suppliers must notify their customers as soon as practical of any exceedance of the Locational Running Annual Average MCL. If the MCL for disinfection byproducts were exceeded, the City of Sacramento would immediately contact the State Division of Drinking Water and the Sacramento County Environmental Health Department. The City would work with these agencies to provide immediate notice to the public. The City of Sacramento would utilize all available communication channels including press releases, social media, notices in public areas, and door-to-door notification in order to ensure that all affected customers are aware of water quality.

What are the health effects of disinfection byproducts in drinking water at levels above the maximum contaminant level?

Some people who drink water containing TTHM in excess of the MCL over many years could experience liver, kidney, or central nervous system problems and increased risk of cancer. Some people who drink water containing HAA5 in excess of the MCL over many years may have an increased risk of getting cancer.

This health effects language is not intended to catalog all possible health effects from disinfection byproducts. Rather, it is intended to inform consumers of some of the possible health effects associated with disinfection byproducts in drinking water when the rule was finalized.

What Is a Public Health Goal?

A Public health Goal (PHG) is the level of a chemical contaminant in drinking water below which there is no significant risk to health. PHGs are not regulatory standards; however, state law requires drinking water standards for chemical contaminants to be set as close to the corresponding PHG as is economically and technologically feasible. In some cases, it may not be feasible to set the drinking water standard for a contaminant at the same level as the PHG. The technology to treat the chemicals may not be available, or the cost of treatment may be very high; these factors must be considered when developing a drinking water standard.

Is Water Safe to Drink if Contaminant Levels Exceed Public Health Goals?

As long as drinking water complies with all MCLs, it is considered safe to drink, even if some contaminants exceed PHG levels. A PHG represents a contaminant level that California Department of Public Health and California’s public water systems should strive to achieve if it is feasible to do so. However, a PHG is not a boundary line between a “safe” and “dangerous” level of a contaminant, and drinking water that complies with MCLs is still considered safe and acceptable for public consumption.