What do SUB’s sampling results mean?

SUB first sampled for PFAS in 2013 as part of the EPA’s Unregulated Contaminant Monitoring Rule, which EPA uses to collect data for contaminants that are suspected to be present in drinking water and do not have health-based standards set under the Safe Drinking Water Act (SDWA). In 2013, SUB did not have detections of any PFAS chemicals. Analytical methods have improved considerably since then. In 2013, the laboratory analysis could detect PFAS chemical concentrations of 0.01 ppb or greater; detection limits are now as low as 0.002 ppb. Moreover, the number of individual chemicals the labs can test for has increased substantially. In other words, more advanced analytical methods are now able to detect a greater variety of chemicals and at incredibly low levels.

In May of 2019, in response to new revelations about PFAS contamination in other parts of the country, SUB developed a voluntary sampling plan for all of its groundwater sources. Samples were analyzed for 18 different PFAS chemicals, the maximum possible with laboratory methods at that time. Of the 24 SUB wells tested, two wells (SP and Sports Way) yielded detectable, but extremely low, concentrations of four PFAS compounds.

SUB continues to voluntarily sample for PFAS at our five entry points, which is where treated water enters the distribution system. The 2021 PFAS data are available in our water quality report. SUB normally presents its water quality data by referencing a maximum contaminant level (MCL), which is a regulatory threshold limit set by the EPA.  There is no MCL for any PFAS chemicals.  However, the EPA has issued a non-regulatory health advisory of 0.070 ppb for PFOA and PFOS combined, and the State of Oregon developed a combined HAL for PFOS, PFOA, PFNA, and PFHxS of 0.030 ppb. The levels SUB has detected are well below the EPA and State of Oregon health advisory levels. SUB takes water quality very seriously and is managing operation of its sources to mitigate against the presence of PFAS.