When it comes to tap water, some people mistakenly believe that a contaminant detected at any level is unsafe, eschewing the toxicological principle that “the dose makes the poison.” This allows many entities – from unscrupulous home filter scammers to advocates with good intentions but questionable tactics – to call into question even the safest glasses of water.

Take the recent Environmental Working Group “Tap Water Database” report that flashed in news feeds over the past couple weeks. EWG has periodically published these reports for many years, and the organization sets its own guidelines for safety – sometimes unachievable by even the advanced treatment – and then calls out local water systems that do not meet those standards. In its report, EWG said it “identified 324 contaminants in drinking water across the country, with detectable levels in almost all community water systems.”

Well, detection does not in and of itself indicate a safety concern. That’s why in the United States we have the Safe Drinking Water Act (SDWA), which provides a common, scientific framework for determining which substances – and at what levels – are health concerns. The vast majority of water providers meet these standards, so we can have a high degree of confidence in the safety of our water. The SDWA sets forth a process for identifying contaminants of concern, and water utilities monitor, test, and treat water to reduce risk for even the most vulnerable consumers.

Still, we should all share EWG’s passion for keeping our water safe and healthy. If you have questions, go straight to the source for answers: your local water utility. Review your annual consumer confidence report or contact your water utility directly. You will find them eager to answer questions about what’s in your water and what they do to keep that water healthy.