BWS ALERTS DOH TO PFAS IN WAIPAHU ʻEWA WAIʻANAE WATER SYSTEM 

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

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.  

# # #

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