Report On Puyallup Drinking Water Unclear About Pollutant Risk

PUYALLUP, WA - A story published Wednesday on Patch.com about pollutants in Puyallup's drinking water, which was based on a report from the nonprofit Environmental Working Group (EWG), was unclear about what's in the city's water. Puyallup's water was found to be in compliance with federal standards, according to EWG, but the group's report on Puyallup's water includes test results from Tacoma water, which might make the overall picture unclear.

Puyallup only gets 1 percent of its water from Tacoma, and so EWG's report might overstate what's in Puyallup's overall water supply. Approximately 27 percent of Puyallup's water comes from wells, and the rest from springs. According to the city's 2016 water quality report, Puyallup's water was below - and in some cases very far below - maximum allowable levels for contaminants.

Read Puyallup's 2016 water quality report

For example, the city measured chloroform at 2.9 parts-per billion (ppb) from its well and spring water sources. But the supply of water from Tacoma had over 30 ppb of chloroform. There is no federal standard for chloroform levels in water, but EWG used California's standard of 1 ppb as the "health guideline."

So, a closer look at the way EWG's report was written shows how pollutant risk can be misleading.

Chloroform is a trihalomethane (TTHM), which are part a class of pollutants created by the use of chlorine in disinfecting water. Puyallup's TTHM content - and TTHMs do have federal standards - are well below health guidelines. Puyallup's spring and well water contains about 5.6 ppb compared to the federal health guideline of 80 ppb. Tacoma water is also below federal standards at 35.9 ppb.

It's important to know what's in your water, but it's also important to have context about what these numbers mean. If you're going by federal health standards, Puyallup's water is well below harmful levels for common pollutants. But EWG's report is also useful in seeing how Puyallup and Washington state match up against different health standards, including California's.

If you have questions or comments about Patch.com's reporting, please contact neal.mcnamara@patch.com.

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