Tapcensus

TTHM (Total Trihalomethanes) violations in Hawaii

1 active public water systems in Hawaii had a TTHM (Total Trihalomethanes) violation in the past three years. What TTHM (Total Trihalomethanes) is and why it matters.

Health effects: Long-term exposure is associated with increased bladder cancer risk. Some studies link high TTHM exposure to adverse reproductive outcomes. Bromodichloromethane is classified as a possible human carcinogen.

Systems with a TTHM (Total Trihalomethanes) violation

Latest quarter first, then largest first
SystemServesStatusRules violated, 3 yrUnresolved
ST Stephen's Diocesan Ctr
Kaneohe · Honolulu County 		45 1 0
About this data

A system is counted once if any of its violations in the past three years involved TTHM (Total Trihalomethanes), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not TTHM (Total Trihalomethanes) alone.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Hawaii records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.