In recent years, the issue of per- and polyfluoroalkyl substances (PFAS) contamination has garnered significant attention from both the public and regulatory bodies alike. These synthetic chemicals, commonly found in a wide array of consumer products and industrial applications, have become a growing concern due to their persistence in the environment and potential adverse effects on human health. The following is a summary of the background of PFAS contaminants, their sources, and the ongoing measures that SMWD is taking to manage and remediate this complex issue.

First and foremost: the drinking water that SMWD provides to its 200,000 residents meets or surpasses all of the water quality standards set by both the state and federal governments.

Our team of water quality experts at SMWD keeps a close watch on water quality throughout the water supply chain—from the source to the tap. The District runs hundreds of laboratory tests every year on water samples taken from customers all across the SMWD service area. We also collaborate with regional partners to monitor the quality of the water from the source, whether it is the Colorado River and/or the Sacramento/San Joaquin Delta, and verify the effectiveness of advanced treatment processes to remove contaminants. You can find these test results in SMWD’s annual water quality report, also known as the Consumer Confidence Report. This report is published on SMWD’s website every July; printed copies are also available upon request.

It should be noted that the majority of the water SMWD provides to customers is imported from the Metropolitan Water District of Southern California. This means that the possibility of the presence of PFAS is dramatically lower than among agencies whose water supply comes from groundwater. Nevertheless, the District is diligent in monitoring and treating its water to ensure the highest quality.

What are PFAS? 

PFAS (Perfluoroalkyl substances) are a group of man-made chemicals that were extensively used in everyday items such as nonstick cookware, stain-resistant fabrics, and firefighting foam due to their ability to repel water and resist stains.

One concern with PFAS arises from their persistence in the environment. These chemicals do not break down readily; they accumulate over time. When they enter water sources, such as rivers or groundwater, they may eventually find their way into groundwater drinking water supplies. 

Certain PFAS chemicals (including perfluorooctanoic acid and perfluorooctanesulfonic acid, also known as PFOA and PFOS, respectively) are no longer manufactured in the United States and several major manufacturers have chosen to stop their use in products. However, these chemicals are still produced internationally and are imported into the US in consumer goods, such as carpets, apparel, textiles, paper, packaging, coatings, rubber, and plastics.

Some studies suggest that prolonged exposure to high levels of PFAS could potentially lead to health problems. Health concerns might include issues with the liver, the immune system, and even an increased risk of certain cancers. People can be exposed to PFAS through food, food packaging, consumer products, and drinking water.

While there are initiatives in place to limit the use of PFAS in consumer products SMWD is dedicated to monitoring and treating for them in groundwater drinking water sources. 

What has been done to regulate PFAS in California?

California has taken a number of steps to protect the public from PFAS in drinking water, including:

The California State Water Resources Control Board’s recently established stringent health advisory levels for several PFAS compounds levels that are even lower than those set by the EPA (see table below). 

The State Water Board’s requirement that public water systems monitor and report PFAS levels in their supplies. This includes testing both source water and treated drinking water.  

If PFAS levels exceed the advisory levels, the State Water Board can take actions to address the contamination, including the use of alternative water sources and treatment. 

The California legislature has passed laws to address PFAS contamination, including measures to regulate and phase out certain PFAS chemicals in firefighting foam and other products. Legal actions have also been taken against manufacturers of PFAS-containing products to hold them accountable for contamination. 

The State continues to invest in research and policy development to better understand the sources and extent of PFAS contamination and its potential impacts on public health. This includes exploring alternative treatment methods to remove PFAS from drinking water.

What are the current regulations? 

Regulations have focused on six different PFAS parameters. The table below is a summary of existing regulations in parts per trillion or nanograms per liter. A nanogram is also known as a “part-per-trillion,” and one nanogram per liter is the equivalent of four grains of sugar dissolved in an Olympic-sized swimming pool.pfas-graph

What are Notification and Response Levels? What are MCLs? What is a Hazard Level?

Notification and Response Levels are precautionary health-based advisory levels established by the California Department of Drinking Water while further research and analysis are conducted by the state to determine the necessity of setting an enforceable drinking water Maximum Contaminant Level (MCL). 

Notification Levels are based on the most sensitive known health endpoints for these compounds: lifetime cancer risk, liver toxicity, and immunotoxicity. These levels are established as early warning indicators of water quality. If these concentrations are reached, the DDW wants the utility to know and take action. 

Response Levels are established at higher concentrations than Notification Levels and DDW discourages public water agencies from serving the water to customers and imposes strict public notice requirements to do so. 

An MCL, is a safety standard established by regulatory authorities to define the concentration of a specific contaminant that is allowed in drinking water without posing a risk to human health. Water suppliers are required to meet this MCL to comply with the Safe Drinking Water Act.

A Hazard Index is a tool used to assess the potential health risks associated with exposure to specific chemical compounds. Rather than establish an MCL for each contaminant, a hazard index established a health-based water concentration based on the toxicity of each PFAS chemical. The proposed Hazard Index for PFHxS, GenX Chemicals, PFNA, and PFBS are calculated by the following formula:


Has our SMWD drinking water been tested for PFAS? 

Yes. Monitoring for the presence of PFAS as well as ongoing and continuous testing remains a priority for SMWD. 

SMWD's imported drinking water has consistently shown no detection of the six PFAS parameters outlined in drinking water regulations.  

While PFAS have been found in the San Juan Basin groundwater which has, historically, been a part of the supply provided to customers in San Juan Capistrano, SMWD’s San Juan Groundwater Plant employs state-of-the-art technology to identify and reduce any PFAS levels to below the proposed regulatory requirements before distributing the treated water for consumption. As a result, all the water provided by SMWD consistently meets both federal and state regulatory requirements, including those that are currently being proposed.

SMWD continues to work alongside the State Board and US EPA as they continue to develop requirements for additional PFAS testing of water supply wells throughout the state. Results from wells in south Orange County are helping us better understand the presence of PFAS in local groundwater.

What about groundwater in the San Juan Basin? 

SMWD has observed PFAS chemicals within the San Juan Basin and has ensured that the best treatment practices are in place to remove this pollution before being delivered in the drinking water system.  

The San Juan Groundwater Plant currently utilizes a reverse osmosis treatment process which efficiently removes PFAS levels to below all regulatory requirements. 

Prior to SMWD managing the San Juan Capistrano water system, the City of San Juan Capistrano utilized a groundwater well called the North Open Space Well. During routine testing prior to SMWD taking over management and operation of the city’s water utility, this well was found to have elevated PFAS levels and was removed from service. It has not pumped any groundwater since 2020. The District is evaluating treatment options that will allow this water source to be returned to service while ensuring high quality drinking water.   

Currently, only residents living in the San Juan Capistrano area receive treated groundwater from the San Juan Basin.  

What is SMWD doing to protect our drinking water from PFAS? 

SMWD takes its responsibility of providing clean drinking water, as well as protecting our groundwater resources very seriously. The District has been proactive in addressing PFAS chemicals through voluntary sampling and close coordination with neighboring agencies as well as state and federal regulators. 

SMWD maintains rigorous standards that meet or surpass all drinking water regulations. SMWD has consistently invested in advanced technology and equipment to ensure that our water undergoes thorough treatment before it reaches our customers. The District maintains open communication and collaboration with regulatory bodies, water suppliers, and our customers to assess any impacts on local water sources, explore potential sources of contamination, and evaluate effective treatment options. 

Transparent and timely communication is a core value for SMWD. We will continue to keep our customers and the public informed about our efforts and any developments related to water quality, including PFAS.


US EPA’s PFAS Information:
Metropolitan Water District PFAS Information:
DW Division of Drinking Water PFAS Information: