Total Trihalomethanes (TTHMs) in California Drinking Water
260 public water systems in California have historical EPA violation records associated with total trihalomethanes (tthms) in the Q2 2026 snapshot.
911
Historical Records in California
260
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
California Systems With the Most Total Trihalomethanes (TTHMs) Records
Jones Academy
290 served11 historical records
F
Mescalero Community
1,961 served5 historical records
A
Nambe Pueblo
800 served4 historical records
D
Jicarilla Dulce
3,064 served3 historical records
A
Laguna Paguate
757 served3 historical records
A
Laguna Valley
4,500 served2 historical records
A
Alabama Coushatta #1 (Eastside)
4,104 served2 historical records
B
Mescalero Inn Of The Mt. Gods
14,542 served2 historical records
A
Kickapoo Traditional Tribe
9,384 served2 historical records
B
Jicarilla South Woodyard
33 served1 historical record
B
Mescalero Carrizo
951 served1 historical record
A
Pojoaque South
3,644 served1 historical record
C
Laguna Encinal
236 served1 historical record
A
Jemez Pueblo
3,200 served1 historical record
C
Kickapoo Housing Complex
499 served1 historical record
A
San Felipe Pueblo
4,335 served1 historical record
A
Santo Domingo Pueblo
5,328 served1 historical record
B
Tunica-Biloxi Tribe of LA
8,103 served1 historical record
A
Alabama Coushatta #2 (Westside)
950 served1 historical record
B
Taos Pueblo
2,652 served1 historical record
A
These counts describe historical compliance records, not present concentrations or household test results. Confirm current conditions with the utility's latest Consumer Confidence Report.