Testing for perfluorinated compounds



OWASA maintains full compliance with and often surpasses all current Federal and State regulations and health advisories. 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 nonstick cookware, stain resistant furniture and carpets, wrinkle free and water repellant clothing, cosmetics, lubricants, paint, pizza boxes, popcorn bags, and many other products. Therefore, 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 (a ppt is comparable to a grain of sand in an Olympic swimming pool). 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 would visit and engage directly with communities impacted by PFAS 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 developed a PFAS Management Plan on February 14, 2019. 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 mentioned above, wastewater systems are not sources of PFAS, but passive receivers from both industrial and domestic sources. Domestic sources include the household use of commercial products such as nonstick cookware, stain resistant furniture and carpets, wrinkle free and water repellant clothing, cosmetics, lubricants, paint, pizza boxes, popcorn bags, and many other products.

To help understand and address industrial discharges of PFAS into wastewater systems, the North Carolina Division of Water Resources (DWR) required 25 utilities with pretreatment programs in the Cape Fear River Basin to sample their wastewater influent for PFAS. If these results exceed a combined concentration of PFOS/PFOA of 70 parts per trillion (ppt), DWR may require these utilities to identify potential sources of PFAS in their wastewater collections system and work with the sources to reduce/eliminate discharges of these compounds.

Although OWASA was not required to participate in this program (because we do not have any significant industrial users in our service area and therefore do not have a pretreatment program) we elected to monitor our wastewater influent and effluent for these compounds proactively following DWR’s methodology. The results (provided in the section below) were consistently below a combined concentration of PFOS/PFOA of 70 ppt.

As it is for the entire water and wastewater industry, the issue of unregulated compounds is of continued interest and importance to OWASA. As an individual utility, OWASA continues to address it proactively 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, analytical methods, 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 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.  

We will continue to engage with the public more comprehensively on water topics such as PFAS. We continue to pursue opportunities to collaborate with community partners on offering joint educational initiatives on PFAS such as the Chapel Hill Library water education series held in Fall 2019.

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

*Drinking water Health Advisory Levels are specifically for PFOA plus PFOS and do not apply to other per- and polyfluoroalkyl 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 are consistent with these findings; OWASA’s treatment process removes 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 how factors such as time of year, season, temperature, rainfall, etc., affect local levels of PFAS.

The results of our quarterly sampling for 2019, shown below, are very consistent with our 2018 results, in 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. Samples were analyzed for 45 different PFAS. Second quarter 2019 samples were collected at the same time that the North Carolina Per and Polyfluoroalkyl Substances Testing (PFAST) Network collected a sample as part of the statewide initiative to sample all raw water sources; our results are also consistent with their findings.

Table with Sampling Data



*OWASA conducted sampling and analysis to correspond with samples and analysis conducted by the North Carolina PFAST Network.

See complete analysis of samples (pdf)


Wastewater:  Below are the Mason Farm Wastewater Treatment Plant influent and effluent sample results for 2019. Samples were analyzed for 25 different PFAS.  All sampling events were consistently below 70 ppt for PFOS and PFOA combined.

See complete analysis of samples (pdf)