Total Trihalomethanes (TTHMs) in Washington Drinking Water
349 public water systems in Washington have historical EPA violation records associated with total trihalomethanes (tthms) in the Q2 2026 snapshot.
776
Historical Records in Washington
349
Systems With Records
About Total Trihalomethanes (TTHMs)
- EPA Limit
- 80 ppb
- Category
- Disinfection Byproducts
- Health Effects
- Liver, kidney, nervous system problems; increased cancer risk
- Common Treatment Approaches
- Activated carbon filters
These counts describe historical compliance records, not present concentrations or household test results. Confirm current conditions with the utility's latest Consumer Confidence Report.