EPA SDWIS DataIdaho

Total Trihalomethanes (TTHM) in Idaho Drinking Water

Idaho has 4,387 public water systems. 3174 have recorded total trihalomethanes (tthm) violations.

Total Systems

4,387

With Violations

3,174

EPA MCL

0.08

Population Served

1.8M

Total Trihalomethanes (TTHM) in Idaho: Key Facts

Total Water Systems

4,387

Systems with Violations

3,174

Lead Violations

21

Copper Violations

108

EPA Standard

0.08 mg/L

Water Systems with Violations in Idaho

SystemPopulationViolations
VALLEY VIEW SUBDIVISION901278
CLEARWATER WATER DIST801066
POCATELLO CITY OF58K961
SIMPLOT WOOD CREEK15910
ASPEN RIDGE SUBD204868
SYMMS FRUIT RANCH INC88682
MISSION CREEK WATER ASSN263674
POST FALLS CITY OF20K658

Health Effects of Total Trihalomethanes (TTHM) Exposure

Cancer risk

Long-term exposure increases bladder cancer risk

Reproductive effects

Some evidence of adverse pregnancy outcomes

Liver/kidney stress

High chronic exposure may stress liver and kidneys

Long-term exposure: increased risk of cancer (bladder). Some evidence of reproductive effects.

Frequently Asked Questions

Is there total trihalomethanes (tthm) in Idaho water?

Idaho has 4,387 public water systems. 3174 have recorded total trihalomethanes (tthm) violations based on EPA SDWIS data. If you are on a private well, your water is not covered by these regulations and should be tested independently.

How can I check my Idaho water for total trihalomethanes (tthm)?

Search for your water system using the WaterCheck system lookup, or contact your utility and request a copy of your Consumer Confidence Report (CCR). The CCR is published annually and lists all detected contaminants, their levels, and the EPA MCLs. For private wells, contact a state-certified lab for independent testing.

What is the EPA limit for total trihalomethanes (tthm)?

The EPA Maximum Contaminant Level (MCL) for total trihalomethanes (tthm) is 0.08 mg/L. Systems that exceed MCLs are required to notify customers and take corrective action.

Total Trihalomethanes (TTHM) at a Glance

Categorydisinfection byproduct
EPA MCL0.08 mg/L

Source

Byproduct of drinking water chlorination; reaction of chlorine with organic matter

How to Filter Total Trihalomethanes (TTHM)

  • +Activated carbon filters reduce TTHMs effectively
  • +Reverse osmosis also removes TTHMs
  • +Letting water sit uncovered may reduce some volatile TTHMs