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, PFASs) has impacted drinking water in other communities in NC. PFASs 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 PFASs can enter lakes, rivers, or groundwater through industrial releases, discharges from wastewater treatment plants, and the use of AFFF. Often, PFASs 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 PFASs contributors as they are conveyors of PFASs 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 PFASs - PFOA and PFOS - in drinking water. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the two PFASs 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 PFASs. 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.


Out of an abundance of caution, OWASA proactively tested collected samples for PFASs analysis in January 2018. These analyses measured the level of 39 PFASs 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 (PFASs).


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 PFASs 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 PFASs but not all. Our test results showed that OWASA’s treatment process was also successful in removing some PFASs but not all.

Raw Reservoir Water: In the University Lake and Quarry Reservoir samples only two PFASs were detected. In the sample from Cane Creek Reservoir, 11 PFASs 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 PFASs were detected. The list of nine compounds detected in the effluent includes all seven PFASs 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 PFASs 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)