Explore water quality in your area.
Find water-quality reports for any U.S. location using data from the U.S. Geological Survey and other public sources.
Trusted data
Water-quality measurements from government agencies and other authoritative sources.
Nationwide
Explore water-quality reported from monitoring locations across the USA.
Clear information
Technical water data and research explained in accessible language.
Public interest
Information intended to help people understand water quality and the evidence behind it.
Featured
Lead in drinking water
How lead gets into tap water, what current rules require, and what households can do.
Microplastics
Microplastics in drinking water? What studies show, what’s unknown, and why EPA delayed nationwide monitoring.
All About Water Contamination
What is in your water, how to read a water quality report, when testing makes sense, and treatment options.
Beyond the data
Water quality is more than a set of measurements. Learn what can affect drinking water, what the evidence tells us about potential risks, and how to make sense of information about your own water.
Understand your water
Learn where drinking water comes from, how it is treated and tested, and how to interpret the information available about it.
Issues & contaminants
Explore substances and conditions that can affect drinking water, from familiar concerns to emerging research.
What can I do?
Find practical ways to investigate concerns, ask better questions, and decide when further action may be warranted.
More from H2O IQ
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- Where does drinking water come from?Most U.S. tap water comes from surface water or groundwater. Rivers, lakes, reservoirs, springs, aquifers, and wells are all part of the larger water cycle—and the source matters because it… Read more: Where does drinking water come from?
- How to read your water-quality reportConsumer Confidence Reports can tell you where your drinking water comes from, which regulated contaminants were detected, and whether the system met applicable standards. The key is knowing what the… Read more: How to read your water-quality report