Testing for perfluorinated compounds



OWASA maintains full compliance with and often surpasses all current Federal and State regulations. According to all current and available science, OWASA’s drinking water is safe for drinking and OWASA’s treated wastewater is safe for the environment. OWASA supports and participates in science-based research to inform these regulations and protect water quality and human health.

Recently, the occurrence and levels of GenX, a compound that belongs to a class of man-made chemicals, known as per- and polyfluoroalkyl substances (together, PFAS) has impacted drinking water in other communities in NC. PFAS are used in a variety of everyday products to increase resistance to water, grease, or stains such as carpet, clothing, fabric for furniture, paper packaging for food, and other materials (e.g., cookware). Thus, they are commonly found in household dust as well as household discharges to wastewater. They are also used in aqueous firefighting foams (AFFF) that are used at airfields as well as in industrial processes.

Detectable concentrations of PFAS can enter lakes, rivers, or groundwater through industrial releases, discharges from wastewater treatment plants, and the use of AFFF. Often, PFAS in water are localized and associated with a specific facility, such as fire training facilities, military bases, domestic airports, and manufacturing sites. Treated effluent from wastewater treatment plants and biosolids land application sites have also been identified as PFAS contributors as they are conveyors of PFAS that enter the wastewater stream from concentrated sources and household products.

In 2016, the EPA established a lifetime Health Advisory Level (HAL) of 70 parts per trillion (ppt) for the combined amount of two PFAS - PFOA and PFOS - in drinking water. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the two PFAS which have been the most extensively produced and studied. Read more.

Prompted by rising interest and concern in PFAS, on May 22-23, 2018 the EPA held a National Leadership Summit on PFAS to share information on ongoing PFAS efforts across the country, identify specific near-term actions for the EPA, and develop risk communication strategies to address public concerns with PFAS. At the Summit, the EPA announced their four-point action plan. Over the coming months, EPA will visit and engage directly with communities impacted by to understand ways the EPA can best support the work that’s being done at the state, local, and tribal levels. Using information from the Summit, community engagements, and written public input provided via https://www.regulations.gov (enter docket number: OW-2018-0270), EPA plans to develop a PFAS Management Plan for release later this year. For more information, see the EPA Summit webpage, EPA news releases (May 22, May 23), and the EPA PFAS webpage.

The Interstate Regulatory Technology Council has created a series of fact sheets and other background information about PFAS. The Water Research Foundation also makes its ongoing PFAS research available to the community.

As it is for the entire water and wastewater industry of many unregulated compounds, this issue is of continued interest and importance to OWASA. As an individual utility, OWASA continues to proactively address it through regional cooperation and communication, the support of local and national research, and open and honest communication with our customers. We support research into the occurrence, primary sources, health impacts, and effective treatment options for PFAS and other unregulated compounds on the forefront of the industry’s research agenda. As we do for all other compounds, we look to the federal and state government to turn this research into science-based laws that protect our community. We will continue to coordinate with nearby communities on analysis and treatment options, recognizing the connectivity of our actions.

Commitment to making information about PFAS accessible 

PFAS research is emerging. It is also complex. OWASA is committed to sharing available information about PFAS with customers in a manner that is accessible – in terms of where and how information is distributed, and with language that is not overly technical. We have developed a background document with information on the timeline of PFAS detection in North Carolina, State and Federal actions, and steps OWASA is taking to monitor for such substances locally. View the OWASA background document here.

We also include PFAS monitoring updates in our quarterly reports to local governments, which we send to the Town of Chapel Hill, Town of Carrboro, and Orange County. We have also sent information directly to customers. In May, OWASA’s 2018 Water Quality Report Card was mailed to all OWASA account holders (more than 20,000 households and businesses) which includes a page dedicated to providing information about PFAS and OWASA’s monitoring program.  

In the coming months, we plan to engage with the public more comprehensively on water topics such as PFAS; for example, through a water education series in the Fall. We are also exploring opportunities to collaborate with community partners on offering joint educational initiatives on PFAS. Our goal is to ensure that community members have access to the information they need, and we encourage customers to contact OWASA anytime if they have questions or would like to request additional information. 

OWASA's PFAS Monitoring Program


OWASA proactively tested collected samples for PFAS analysis in January 2018. These analyses measured the level of 39 PFAS in OWASA’s raw source waters, treated drinking water, and treated wastewater effluent as well as the raw well water source for the Cane Creek Reservoir Recreation Facilities water system, process water within the water treatment plant, and Morgan Creek upstream of the wastewater effluent discharge. Below are some key findings:

*Drinking water Health advisories are specifically for PFOA and PFOS and do not apply to other perfluoroalkyl substances (PFAS).

GenX was not detected in any sample.

Finished Drinking Water: Two treated drinking water samples were collected, one as water left the Jones Ferry Water Treatment Plant and one from the distribution system. The same seven PFAS were detected in each sample at very similar levels. The sum of PFOS and PFOA in these samples was well below the 70 ppt health advisory level (13.7 in one sample and 18.0 ppt in the other). Studies indicate that the use powder activated carbon (PAC) is successful in the removal of some PFAS but not all. Our test results showed that OWASA’s treatment process was also successful in removing some PFAS but not all.

Raw Reservoir Water: In the University Lake and Quarry Reservoir samples only two PFAS were detected. In the sample from Cane Creek Reservoir, 11 PFAS were detected. The sum of PFOS and PFOA in University Lake, Quarry Reservoir, and Cane Creek Reservoir were 4.7, 4.9, and 120 ppt, respectively. The definite sources of PFOS and PFOA in the Cane Creek Reservoir are unknown. There are no facilities typically associated with elevated levels of PFAS in the watershed, although we do not have specifics on past land use. We do know that other utilities apply biosolids in the watershed; OWASA does not.

Wastewater: In the Mason Farm Wastewater Treatment Plant effluent sample, nine PFAS were detected. The list of nine compounds detected in the effluent includes all seven PFAS detected in the drinking water samples and two additional compounds. Five of these compounds were present at similar levels to that in the drinking water samples.

Upstream Morgan Creek: Eight PFAS were detected in the sample collected from Morgan Creek upstream of where the Mason Farm Wastewater Treatment Plant effluent is discharged. These were the same eight compounds detected in the effluent sample; one additional compound was detected in the effluent and not in the creek sample. Four of the compounds were present at similar levels in the creek and effluent samples.

See complete analysis of samples (pdf)

Read memo to OWASA Board of Directors (March 8, 2018, updated from February 22, 2018 version)

In light of the 2018 results, OWASA is collecting samples quarterly from Cane Creek Reservoir and our treated drinking water for analysis of PFAS.  We want to understand: do factors such as time of year, season, temperature, rainfall, etc., affect local levels of PFAS.


The results of our first and second quarter sampling for 2019 are very consistent with our 2018 results, meaning that we detected low levels of PFOS and PFOA in our treated drinking water samples far below the EPA’s Health Advisory Level (HAL) of 70 parts per trillion (ppt) for PFOS and PFOA combined (a ppt is comparable to a grain of sand in an Olympic swimming pool). Second quarter 2019 samples were collected at the same time that the PFAST Network collected a sample as part of the statewide initiative to sample all raw water sources; our results are consistent with their findings. Results of our third quarter sampling for 2019 are more similar to Q1 2018; treated drinking water remains well below the EPA's HAL.

See complete analysis of samples (pdf)