Disinfection byproducts · 2024
TTHM in St Louis, MO tap water
St Louis, MO's 2024 TTHM measurement is below the federal limit of 80 ug/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Reported level Sample Point | 3 ug/L | 80 ug/L MCL |
Range Distribution | 7.6–30.1 ug/L | 80 ug/L MCL |
Range Distribution | 6.2–19.7 ug/L | 80 ug/L MCL |
Range Distribution | 5.9–27.8 ug/L | 80 ug/L MCL |
Range Distribution | 6.8–30.5 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 12.9 ug/L | 80 ug/L MCL |
Range Distribution | 6.5–20.3 ug/L | 80 ug/L MCL |
Reported level Sample Point | 1 ug/L | 80 ug/L MCL |
Range Distribution | 7–22.4 ug/L | 80 ug/L MCL |
Reported level Sample Point | 10 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 12.9 ug/L | 80 ug/L MCL |
Reported level Sample Point | 4 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 13.3 ug/L | 80 ug/L MCL |
Maximum System-wide | 30.5 ug/L | 80 ug/L MCL |
Reported level Sample Point | 11 ug/L | 80 ug/L MCL |
Reported level Sample Point | 2 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 18.2 ug/L | 80 ug/L MCL |
Range Range Detected | 5.9–30.5 ug/L | 80 ug/L MCL |
Reported level Sample Point | 8 ug/L | 80 ug/L MCL |
Reported level Sample Point | 5 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 14.4 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 15.9 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 17.9 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 12.9 ug/L | 80 ug/L MCL |
Reported level Sample Point | 6 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 13.9 ug/L | 80 ug/L MCL |
Range Distribution | 6.6–26.4 ug/L | 80 ug/L MCL |
Reported level Sample Point | 9 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 16.3 ug/L | 80 ug/L MCL |
Reported level Sample Point | 12 ug/L | 80 ug/L MCL |
Range Distribution | 6.5–20.3 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 16.2 ug/L | 80 ug/L MCL |
Reported level Sample Point | 7 ug/L | 80 ug/L MCL |
Range Distribution | 6.2–27.3 ug/L | 80 ug/L MCL |
Range Distribution | 6.6–19 ug/L | 80 ug/L MCL |
Range Distribution | 6.8–29.9 ug/L | 80 ug/L MCL |
Range Distribution | 6.7–21.6 ug/L | 80 ug/L MCL |
Running annual avg Distribution | 18 ug/L | 80 ug/L MCL |
Verbatim from St Louis, MO's 2024 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 St Louis, MO compares
5 of the 395 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 St Louis, MO tap water?
Yes — St Louis, MO's 2024 Consumer Confidence Report lists TTHM at 18.2 ug/L. St Louis, MO's 2024 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 395 systems on The Water Map measuring TTHM report it at or above the federal limit. Examples include Albuquerque, NM, City of Hemet, CA, City of Menifee, CA.
+Where does this TTHM measurement come from?
This page reproduces the TTHM entry from the 2024 Consumer Confidence Report published by the St Louis, MO 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/mo/st-louis/2024/source.