Disinfection byproducts · 2025
TTHM in SFPUC City Distribution Division, CA tap water
SFPUC City Distribution Division, CA's 2025 TTHM measurement is below the federal limit of 80 UG/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average Distribution | 40.24583333333333 UG/L | 80 UG/L MCL |
Highest single sample Distribution | 64.8 UG/L | 80 UG/L MCL |
Verbatim from SFPUC City Distribution Division, CA's 2025 Consumer Confidence Report — source document ↗
About TTHM
Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter.
Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.
How SFPUC City Distribution Division, CA compares
5 of the 458 systems measuring TTHM on The Water Map have it at or above the federal limit:
Nearby systems also reporting TTHM:
People also ask
+Is there TTHM in SFPUC City Distribution Division, CA tap water?
Yes — SFPUC City Distribution Division, CA's 2025 Consumer Confidence Report lists TTHM at 40.24583333333333 UG/L. SFPUC City Distribution Division, CA's 2025 TTHM measurement is below the federal limit of 80 UG/L (MCL).
+What's the federal limit for TTHM in drinking water?
The federal MCL for TTHM is 80 UG/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is TTHM?
Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.
+Which other U.S. cities have TTHM over the federal limit?
5 of the 458 systems on The Water Map measuring TTHM report it at or above the federal limit. Examples include Albuquerque, NM, Columbus, OH, Hollywood, FL.
+Where does this TTHM measurement come from?
This page reproduces the TTHM entry from the 2025 Consumer Confidence Report published by the SFPUC City Distribution Division, CA water utility — the annual drinking-water report every U.S. utility is required by federal law to publish. The original source document is archived at /water/ca/sfpuc-city-distribution-division/2025/source.