What are Public Health Goals? Maximum Contaminant Levels and water regulations in California

Public Health Goals (PHG) are often mistaken as law, however they are goals set by the state as to what level a contaminant no longer poses a significant health risk. They are not regulated, but are established as a recommendation by the Office of Environmental Health Hazard Assessment (OEHHA). Conversely, Maximum Contaminant Levels (MCL) are standards set by the United States Environmental Protection Agency (EPA) to keep public water systems safe. The MCL is the legal limit on how much of a constituent/ contaminant can be found in drinking water.  MCLs are enforceable and regulated.


The California State Water Resources Control Board (SWRCB) reviews public health goals, however the determination of safe contaminant levels is dependent on the available technology  and the feasibility of removing a contaminant  before determining drinking water standards. Public Health Goals are established based on extensive testing, even by studying the impacts on the people who have been exposed to certain contaminants. Scientific evidence of all health hazards relating to constituents / contaminants in water is collected and studied to create recommended Public Health Goals that will not harm humans.

According to the OEHHA, “Professional staff includes toxicologists, epidemiologists, physicians, biostatisticians, and research scientists who are responsible for assessing health risks posed to the public by hazardous chemicals. The Office provides its scientific expertise in this area to other state regulatory agencies. Through its risk assessments and its development of PHG, OEHHA assists SWRCB in developing regulatory standards for chemicals in the state’s drinking water.”


Contaminants, also called constituents, are often naturally occurring. While optimally, the absence of contaminants would be preferred, the economics and available technology can limit the ability to achieve such goals. Health officials from the EPA, SWRCB and OEHHA evaluate lab results and current law to establish public health goals. It is the responsibility of public water systems in the state to monitor and report water quality to meet both federal and state regulations.

Public Health Goals are instrumental in guiding drinking water law and protecting human health, but it is important to note that they are not legal limits. Some MCLs are higher than PHGs, but this does not pose a health risk. The PHGs are established as a goal whenever feasible, however the MCLs are considered safe levels of contaminants. Public water agencies are required to inform their customers of contaminants levels each year. All public information on water quality is contained in an annual water quality report, also known as a consumer confidence report. These reports contain legal MCLs and the results of testing.


If a constituent is detected that exceeds the MCL, the public water agency must notify the customer of the detection and possible health risks. All notices sent to customers must be approved by the SWRCB. Public water agencies continue to play an integral part in the monitoring and protection of our drinking water supply. For questions about your specific water quality report, contact your local water agency or visit their website to download a copy.