Disinfection byproducts · 2024
TTHM in Seattle, WA tap water
Seattle, WA's 2024 TTHM measurement is below the federal limit.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average System-wide | 43 ug/L | None set |
Range System-wide | 25 ug/L | None set |
Verbatim from Seattle, WA'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 Seattle, WA compares
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People also ask
+Is there TTHM in Seattle, WA tap water?
Yes — Seattle, WA's 2024 Consumer Confidence Report lists TTHM at 43 ug/L. Seattle, WA's 2024 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 2024 Consumer Confidence Report published by the Seattle, WA 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/wa/seattle/2024/source.