J. Wayne Miller, Ph.D Water Treatment Plant
YLWD is home to the Nation's Largest PFAS Water Treatment Plant
PFOA and PFOS are man-made chemicals that are part of a larger family known as “forever chemicals” or Per- and polyfluoralkyl substances (PFAS). Since the 1940s, they have been used to manufacture everyday household products such as make-up, frying pans, and pizza boxes, as well as in various industrial applications. These chemicals have been detected in water throughout the nation, including in Orange County. Studies have shown that these chemicals, over a long period of exposure, pose a possible health risk.
On February 6, 2020, the Division of Drinking Water changed its response levels for these chemicals. Since PFOA and PFOS have been found in low levels in YLWD’s groundwater wells, YLWD partnered with the Orange County Water District to construct a treatment plant, the largest plant of its kind in the nation. 
The District researched and tested many technologies that could be used to remove PFOA and PFOS from water and ultimately decided to construct an Ion Exchange (IX) plant, a well-established treatment technology.
Our PFAS Water Treatment Plant was completed in December 2021 and is the largest of its kind in the nation with 6 pre-filter units, 22 Ion Exchange vessels, a 25 MGD booster pumping station, and a 1000 kW natural gas back-up generator. The plant distributes treated water to our community at an operating capacity of 19 million gallons of water per day.
It’s innovative and valuable projects like our PFAS Water Treatment Plant that ensure YLWD continues to deliver safe and reliable drinking water to our customers, every day. You can learn more about PFOA and PFOS and YLWD’s actions at ylwd.com/pfos-and-pfoa. Additional information from the State Water Board is available at www.waterboards.ca.gov/pfas.
Construction Video
PFAS: PFoa and pfos
Delivering safe drinking water to our customers is our highest priority. Our water quality staff continuously monitor water supply and conduct thousands of laboratory tests each year to make sure that we are delivering safe water to all of our customers. The drinking water that we deliver meets all water quality standards set by both the state and federal government and is below the EPA health advisory level for PFOA and PFOS.
Learn more about PFOA / PFOS from the Orange County Water District
What are pfas
overview
The Orange County Water District (OCWD) strives to deliver safe, reliable drinking water to 2.5 million customers every day. OCWD and the water agencies in its service area are committed to operating in compliance with all state and federal guidelines and regulatory requirements.
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are chemicals that are prevalent in the environment and were once commonly used in many consumer products. Through an ongoing investigation, California and many other states have found that PFAS has made their way into our groundwater, particularly near airports and military bases where these chemicals are commonly used.
OCWD and local water retailers are actively engaged with federal and state regulators and elected and appointed officials on this issue. As part of its commitment to transparency, OCWD provides regular PFAS updates to community stakeholders.
For more background information, please see the materials below:
Regulatory Happenings
Local Activities
OCWD and its consultant, Jacobs, are working to install the pilots into the new building and are finalizing the design of the pilot test. It’s anticipated that pilot testing will begin in November.
After receiving submissions for its Request for Proposals for a PFAS Treatment Systems Planning Study, OCWD has selected Carollo Engineers to lead the Study. The goal of the Planning Study is to help OCWD and its 11 retail agencies who may require treatment for their groundwater wells. The Planning Study will assess the number of wells impacted, location of wells, and areas available for a treatment system(s).
OCWD will continue to work with Intertox and the state as further regulatory changes are considered.
OCWD also continues to work with other stakeholders throughout the state to share information and updates on PFAS issues.
For more information on upcoming events, please contact Gina Ayala.
Learn more about PFAS from YLWD’s Board Director Wayne Miller’s presentation at the 2019 OC Water Summit.
pfas Frequently asked questions
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are man-made chemicals that have been used in a variety of industrial and commercial products since the 1940s. They are part of a larger group referred to as per-and polyfluoroalkyl substances (PFAS). Although most PFAS chemicals are no longer manufactured or used in the United States, other countries still make products that contain these chemicals, which may be imported into the United States.
According to the U.S. Environmental Protection Agency (EPA), “PFAS can be found in:
- Food packaged in PFAS-containing materials, processed with equipment that used PFAS, or grown in PFAS-contaminated soil or water.
- Commercial household products, including stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams (a major source of groundwater contamination at airports and military bases where firefighting training occurs).
- Workplace, including production facilities or industries (e.g., chrome plating, electronics manufacturing, or oil recovery) that use PFAS.
- Drinking water, typically localized and associated with a specific facility (e.g., manufacturer, landfill, wastewater treatment plant, firefighter training facility).
- Living organisms, including fish, animals, and humans, where PFAS have the ability to build up and persist over time.”
For more information, visit EPA’s website at https://www.epa.gov/pfas/basic-information-pfas#exposed.
The EPA collects data for potential contaminants that may be present in drinking water under its Unregulated Contaminant Monitoring program. These data have historically been used by EPA as a primary source of information to make regulatory decisions. In 2012, EPA implemented its third Unregulated Contaminant Monitoring Rule (UCMR3), which included testing for PFAS contaminants.
From 2013 through 2015, the Orange County Water District (OCWD) performed UCMR3 testing for Orange County groundwater retail agencies. YLWD is one of five water agencies in OCWD’s service area that found detections of PFOA and PFOS.
Groundwater is pumped out of the Orange County Groundwater Basin, which is managed by the Orange County Water District (OCWD). OCWD has been working to identify potential sources of PFAS. To date, OCWD has determined that neither water produced by its Groundwater Replenishment System (GWRS) project nor imported water purchased from the Metropolitan Water District (MWD) are a source of PFAS to the groundwater basin. Testing of Santa Ana River surface water has revealed the presence of PFAS, including PFOA and PFOS. For more information, visit OCWD’s website at https://www.ocwd.com/what-we-do/water-quality/.
The EPA provides health advisories as guidance for determining if concentrations of unregulated chemicals in drinking water are safe for public consumption. Health advisories are non-enforceable and non-regulatory.
In May 2016, the EPA issued a new health advisory level of 70 parts per trillion (ppt) for the sum of PFOA and PFOS concentrations. This health advisory level is based on a lifetime of exposure to PFOA and PFOS. One part-per-trillion or one nanogram per liter is the equivalent of one grain of sand in an Olympic-sized swimming pool. For more information, visit EPA’s website at https://www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos.
The EPA and the State of California have established procedures for developing drinking water standards, also known as Maximum Contaminant Levels, or MCLs. An MCL is the highest level of a contaminant allowed in drinking water and is considered safe for long-term consumption. When a new unregulated contaminant is found, the state and federal agencies determine if it warrants regulation. They may conduct studies on toxicology, occurrence, treatment, environmental fate and transport, and other factors. After a thorough analysis of the facts, an MCL may be proposed and enacted. To date, MCLs have not been established for the PFAS chemicals.
In July 2018, the State Water Resources Control Board (SWRCB) Division of Drinking Water (DDW) established Notification Levels for PFOA and PFOS at 14 ppt and 13 ppt, respectively. Notification Levels are precautionary health-based advisory levels established by DDW while further research and analysis are conducted by the State and EPA to determine the necessity of setting enforceable drinking water MCLs and what the levels should be. The Notification Levels are based on the most sensitive known health endpoints for these compounds: lifetime cancer risk, liver toxicity, and immunotoxicity. For more information, visit SWRCB’s website at https://www.waterboards.ca.gov/pfas/.
Treatment systems that remove PFOA and PFOS from water include activated carbon filters, ion exchange resins, and reverse osmosis membranes.
The Yorba Linda Water District has been proactive in addressing PFAS since learning about these compounds in our water. YLWD has:
- Provided PFAS test results to our customers in YLWD’s annual Water Quality Reports even though not required;
- Conducted frequent testing and monitoring of these contaminants since the EPA health advisory of May 2016;
- Developed a blending strategy to reduce concentrations of PFOA and PFOS in water delivered to our customers;
- Participated in technical meetings and met with experts on treatment technologies;
- Developed plans if concentrations exceed the federal or state standards;
- Worked as part of wide-ranging teams in the Orange County area to share the latest regulatory and test information and to identify the source of the PFAS.