Disinfection byproducts · 2025
TTHM in Grand Rapids, MI tap water
Grand Rapids, MI's 2025 TTHM level is between 80% and 100% of the federal limit — measured but not in violation.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Reported level Detected In | 59 ug/L | None set |
Minimum System-wide | 17 ug/L | None set |
Maximum System-wide | 70.7 ug/L | None set |
Verbatim from Grand Rapids, MI'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 Grand Rapids, MI compares
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People also ask
+Is there TTHM in Grand Rapids, MI tap water?
Yes — Grand Rapids, MI's 2025 Consumer Confidence Report lists TTHM at 70.7 ug/L. Grand Rapids, MI's 2025 TTHM level is between 80% and 100% of the federal limit — measured but not in violation.
+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 Grand Rapids, MI 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/mi/grand-rapids/2025/source.