HONOLULU (HawaiiNewsNow) – The Department of Water Supply (DWS), County of Hawaii, has detected low levels of Perfluorooctanesulfonic acid (PFOS) for the first time in Kula‘imano Well A (makai) during voluntary drinking water well testing across the island.
PFOS is part of the group of perfluoroalkyl and polyfluoroalkyl substances (PFAS). DWS reported the findings to the Hawaii Department of Health (DOH).
The testing results ranged from 2.6 to 3.0 nanograms per liter. These results are within the acceptable limits of the safe drinking water standards set by the Environmental Protection Agency. The EPA’s Maximum Contaminant Level for PFOS is 4.0 ng/L.
Kula‘imano Well A is one of two groundwater sources in the Pepe‘ekeo Water System. The primary groundwater source is Kula‘imano Well B (mauka), which is currently under repair.
PFAS are concerning for their persistence in the environment and links to adverse health outcomes in humans and animals, especially at high concentrations or with long-term exposure.
PFOS is one of thousands of human-made compounds that have been commonly used in non-stick, non-stain, and water-resistant industrial and household products since the 1940s.
In 2002, the primary US manufacturer of PFOS voluntarily phased out production of this chemical compound.
“Our customers’ safety is our top priority,” said Keith Okamoto, DWS Manager-Chief Engineer. “Although the new federal compliance regulations do not take effect for a couple of years, we did not want to wait to act. We are proactively sampling active drinking water sources across the island, over 60 locations, by the end of the year.”
Okamoto added, “The drinking water DWS provides meets all federal and state drinking water standards – it is safe to use and drink.”
In addition to sampling its wells, DWS will be testing the use of granular activated carbon for PFAS treatment implementation. The tests are scheduled to begin in early 2026.
Click here for more information.
Copyright 2025 Hawaii News Now. All rights reserved.
