News Releases from Department of Health

Note: This news release updates and corrects a previous release issued March 31.

CORRECTION: The Department of Health has identified an inaccuracy in the map shared by the Honolulu Board of Water Supply regarding the impacted water system. To ensure clarity and accuracy, DOH has created an updated map that correctly reflects the public water system affected by the initial detection.

The updated map excludes PWS 355 Barbers Point, which is currently operated and owned by Hawaii Water Service (HWS). Customers of HWS are not subject to the notice and receive their water from another source.

Individuals with questions about whether they are in the impacted service area should contact the Board of Water Supply.

HONOLULU — PFAS (perfluoroalkyl and polyfluoroalkyl substances) has been detected in water samples collected at the Hōʻaeʻae Wells Granular Activated Carbon (GAC) Treatment Facility of the Waipahu ʻEwa Waiʻanae water system [Public Water System HI0000335, owned by Honolulu Board of Water Supply (BWS)] which serves the west area of the island of O‘ahu from ʻEwa Beach to Mākaha including Kapolei, Nānākuli and Waiʻanae.

The detection of PFAS at the Hōʻaeʻae Wells Granular Activated Carbon (GAC) Treatment Facility was confirmed by multiple samples collected from Nov. 20, 2024, to Feb. 14, 2025. The BWS notified the Hawaiʻi Department of Health (DOH) of the initial detection of PFAS through an email on March 19, 2025. The detected PFAS level is listed in the table below.

PFAS Chemical	PFAS Chemical Abbreviation	Detected Levels (ng/L)11	Maximum Contaminant Level (MCL) (ng/L)2
Perfluorohexanoic Acid	PFHxA	2.0-2.2	NA*
Perfluoropentanoic Acid	PFPeA	2.0-3.1	NA*

 *MCLs not set by EPA

ADDITIONAL INFORMATION: The concentrations of PFAS detected at the Hōʻaeʻae Wells Granular Activated Carbon (GAC) Treatment Facility of the Waipahu ʻEwa Waiʻanae water system are unlikely to pose any public health risk.

While these specific PFAS compounds are not currently regulated by the U.S. Environmental Protection Agency (EPA), the Department of Health has established environmental action levels (EALs) for Perfluorohexanoic Acid and Perfluoropentanoic Acid for groundwater, which can be utilized as a drinking water source. EALs are risk-based guidelines to decide when pollution in soil, water, or air might require further investigation or cleanup to protect people and the environment. The detections at the Hōʻaeʻae Wells GAC Treatment Facility are well below the groundwater EALs.

According to the Environmental Protection Agency (EPA), PFAS, which have been used since the 1940s, are fluorinated organic chemicals that have been used extensively in consumer products such as carpets, clothing, fabrics for furniture, paper packaging for food and other materials (e.g., cookware) designed to be waterproof, stain-resistant or nonstick. They are also a component of fire-fighting foam and have many industrial uses.

For more information on PFAS, please see https://www.epa.gov/pfas or https://health.hawaii.gov/pfas. Users may also contact BWS.

This press release is issued in accordance with Hawaii Revised Statutes (HRS) Section 340E- 24(b).

Acronyms and Definitions

DOH – Hawaiʻi Department of Health, responsible for regulation and oversight of impacts to the environment and health of the people in Hawaiʻi. This includes regulated drinking water systems.

EPA – The U.S. Environmental Protection Agency is responsible for the protection of human health and the environment on a national level.

HRS – Hawaii Revised Statutes are laws enacted by the state legislature.

MCL – Maximum Contaminant Level, set by EPA, is the highest level of a contaminant that is allowed in drinking water.

PFAS – Perfluoroalkyl and Polyfluoroalkyl substances, fluorinated organic chemicals that have been used extensively since the 1940s.

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1. ng/L = nanogram per liter = parts per trillion (ppt)   ↩︎
2. ng/L = nanogram per liter = parts per trillion (ppt) ↩︎