Disinfection byproducts · 2025
TTHM in Cary, NC tap water
Cary, NC's 2025 TTHM measurement is below the federal limit.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Running annual avg System-wide | 37 ug/L | None set |
Range System-wide | 17–43 ug/L | None set |
Verbatim from Cary, NC'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 Cary, NC compares
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People also ask
+Is there TTHM in Cary, NC tap water?
Yes — Cary, NC's 2025 Consumer Confidence Report lists TTHM at 37 ug/L. Cary, NC's 2025 TTHM measurement is below the federal limit.
+What's the federal limit for TTHM in drinking water?
The EPA has not set an enforceable federal limit for TTHM. Utilities still report any measured levels in their annual Consumer Confidence Report.
+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.
+Where does this TTHM measurement come from?
This page reproduces the TTHM entry from the 2025 Consumer Confidence Report published by the Cary, NC 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/nc/cary/2025/source.