TapScore USA

Total Trihalomethanes (TTHMs) in Drinking Water

Reference information plus historical EPA compliance records associated with total trihalomethanes (tthms).

EPA Limit (MCL)

80 ppb

EPA Goal (MCLG)

N/A ppb

Category

Disinfection Byproducts

Regulatory values are a concise reference, not legal or medical advice. Confirm the current standard and rule-specific details on EPA.gov.

Health Effects

Liver, kidney, nervous system problems; increased cancer risk

Common Sources

Byproduct of drinking water disinfection

Treatment Considerations for Total Trihalomethanes (TTHMs)

Commonly cited treatment approaches include: Activated carbon filters. Choose treatment only after a certified water test identifies the substance and concentration; verify NSF/ANSI certification and consult a qualified local professional when needed.

40,352

Historical Violation Records

9,356

Systems With Records

Historical Total Trihalomethanes (TTHMs) Records by State

StateRecordsSystems
Oklahoma7,247506
Florida3,712854
Pennsylvania3,6901,192
Louisiana3,121373
North Carolina2,212568
Alaska2,029166
Ohio1,511441
Texas1,499280
West Virginia1,247252
Oregon1,185370
Kentucky1,068212
Arkansas1,036130
California911260
Missouri875202
Illinois855424
Washington776349
Puerto Rico672114
Colorado638243
Connecticut569206
Virginia523175

Systems With the Most Total Trihalomethanes (TTHMs) Violation Records

BARNSDALL

1,243 served108 historical records
F

RYAN UTILITIES AUTHORITY

800 served102 historical records
F

OKMULGEE PWA

13,495 served95 historical records
F

DEERING UTILITY SYSTEM

160 served92 historical records
F

VILLAGE OF CALVIN WATER SYSTEM

591 served90 historical records
F

MUSKOGEE CO. RWD #3

1,300 served89 historical records
F

WAURIKA PUBLIC WORKS AUTHORITY

2,100 served87 historical records
F

PLEASANT HILLS-CROSSROADS WATER SYSTEMS

840 served85 historical records
F

COMANCHE PUBLIC WORKS AUTHORITY

1,649 served85 historical records
F

CLEVELAND MUNICIPAL AUTHORITY

3,262 served83 historical records
F

Frequently Asked Questions

What is Total Trihalomethanes (TTHMs) and why can it appear in drinking-water records?

Total Trihalomethanes (TTHMs) can be associated with drinking water through: Byproduct of drinking water disinfection.

What reference value does this page show?

The summarized EPA Maximum Contaminant Level is 80 ppb. Some substances use action levels or rule-specific thresholds instead, so verify the current EPA standard.

Does a historical violation record mean it is in my tap today?

No. A compliance record may be historical or resolved. Use the latest Consumer Confidence Report or a certified test for current local conditions.