How useful is it to judge water quality by each state?
Depending on their size and governance, states can have sprawling water systems with multiple suppliers and sources. Water networks are often separated into municipalities, which are further differentiated by public suppliers, private wells, and different types of source water (lakes vs reservoirs, vs groundwater, etc.) In other words, one state can be home to drastically different types of tap water, depending on the exact geography and infrastructure of a particular location.
That said, there are often general trends in state water quality—both over time and by area. For example, as the home of the country’s largest and most extensive treatment works, New York’s supply has long been considered excellent. Likewise, places with hard water-causing limestone bedrock won’t see it shifting anytime soon. And, major infrastructural changes to water supplies usually occur over years rather than months. So, think of this list as one useful resource that should form part of a wider look into water quality. We’d recommend you pair this information with any current updates by your state and local suppliers.
How accurate is this article?
We’ve compiled this list based on ranking data and information from the authorities responsible for ensuring water safety and monitoring contaminants. This includes the EPAs ECHO tool, EPA-mandated Consumer Confidence Reports, and state compliance summaries. We’ve also drawn information from media outlets and nonprofit organizations that use EPA and other data to undertake comprehensive assessments of nationwide water purity, such as U.S. News, the AWWA, and the EWG. Where available and deemed credible, we’ve included secondary and independent evaluations of water quality. For example, there may be a relevant local news report on water issues, a study by a local college, or other commonly voiced opinions on regional water quality. In all cases, we’ve traced claims to their primary sources and provided a list of references at the end of this article.
It’s important to recognize that water quality changes over time, sometimes drastically, in response to sudden environmental events such as flooding or industry spillage. As such, please use this resource as a general guide rather than the authority on state water. For an accurate picture of water purity at any specific time, always reach out to your local supplier.