EPA SDWIS DataWisconsin

Total Trihalomethanes (TTHM) in Wisconsin Drinking Water

Wisconsin has 24,118 public water systems. 13271 have recorded total trihalomethanes (tthm) violations.

Total Systems

24,118

With Violations

13,271

EPA MCL

0.08

Population Served

5.1M

Total Trihalomethanes (TTHM) in Wisconsin: Key Facts

Total Water Systems

24,118

Systems with Violations

13,271

Lead Violations

59

Copper Violations

355

EPA Standard

0.08 mg/L

Water Systems with Violations in Wisconsin

SystemPopulationViolations
WAUKESHA WATER UTILITY71K2969
52ND AVE WATER GROUP351760
SOUTH PETERSON WELL ASSOC241446
BROAD-A CORPORATION31306
SILVER SPRING GOLF CENTER CLUBHOUSE6001265
SUSSEX VILLAGE HALL & WATER UTILITY12K1254
MAPLE RIDGE ESTATES251161
WILMOT UNION HIGH SCHOOL1K1121

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 Wisconsin water?

Wisconsin has 24,118 public water systems. 13271 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 Wisconsin 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