TRACE LEVELS OF SELENIUM DETECTED IN MAKAWAO WATER SYSTEM

HONOLULU - Trace levels of selenium have been detected for the first time in water samples collected at Haʻikū Well Chlorinator, which is part of the County of Maui Department of Water Supply's (MDWS) Makawao water system (Public Water System HI0000213) serving the Makawao area of the island of Maui.

The detected selenium levels ranged from 3.7 to 4.9 micrograms per liter (ug/L), which are below the U.S. Environmental Protection Agency (EPA) and Hawaiʻi Department of Health (DOH) Maximum Contaminant Level for selenium of 50 ug/L. The detected levels are unlikely to pose a public health risk.

Selenium was detected in samples collected on May 29, 2026, and June 19, 2026. MDWS notified DOH of the initial detection via phone and email on July 6, 2026.

Selenium is a naturally occurring mineral element that is distributed widely in nature in most rocks and soils. The presence of selenium in drinking water can be attributed to the erosion of natural mineral deposits.

To date, MDWS is and continues to be in compliance with the federal and state selenium standard for drinking water. Impacted users can contact the Maui Department of Water Supply.

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Map of the service area of Makawao Water System. Note the excluded areas.