About WaterQ
WaterQ makes US drinking water quality data accessible and understandable for everyone. We believe every person has the right to know what's in the water they drink.
Our Mission
The US Environmental Protection Agency (EPA) collects extensive data on public water systems through the Safe Drinking Water Information System (SDWIS). While this data is publicly available, it can be difficult for everyday consumers to access, interpret, and act upon.
WaterQ transforms a selected set of regulatory records into water quality reports. Our goal is to help communities with the information they need to advocate for clean, safe drinking water. If you are new, start with our practical guide to reading a water quality report.
What We Provide
Water Quality Scores
A score is shown only when supporting system records are available. It summarizes documented detections and violations; it is not a current tap water safety test.
Contaminant-Matched Filter Guide
Our filter guide matches the specific contaminant detected in your water to the NSF-certified filter type actually proven to remove it, instead of generic "best filters" advice.
Open Regulatory Records
Instant, direct access to federal SDWIS compliance histories, monitoring metrics, and exceedance notices without requiring registration, logins, or paid subscriptions.
Contaminant Reports
Detailed breakdowns of every tested contaminant, including how measured levels compare to EPA Maximum Contaminant Levels (MCLs) and potential health effects.
Violation Tracking
Complete records of regulatory violations, including whether they have been resolved and their severity level.
Geographic Comparisons
Compare water quality across states, counties, and cities to understand regional patterns and identify areas of concern.
Data Sources
WaterQ aggregates data from several authoritative federal sources:
- EPA SDWIS — The Safe Drinking Water Information System is our primary data source, providing water system inventory, violation history and lead/copper sample results. SDWIS covers more than 150,000 public water systems; WaterQ currently carries records for 7,929 of them, covering the most populous 3,000 US cities.
- EPA ECHO bulk SDWA files — How we actually obtain SDWIS data: the public water system inventory, violation and enforcement history, and Lead and Copper Rule sample results.
- Open-Meteo — Current precipitation shown on city pages as runoff context. It is weather data, not a water quality measurement, and does not affect any score.
Data is updated on a quarterly basis to align with EPA reporting cycles. For the most current information, please visit the Data Sources page.
Scoring Methodology
Our water quality scoring system evaluates each public water system on a 0–100 scale based on contaminant test results and violation history. The methodology accounts for:
- Contaminant concentrations relative to EPA Maximum Contaminant Levels (MCLs)
- Contaminant-specific risk weights (higher weight for known carcinogens and high-risk substances)
- Time decay to prioritize recent test results over older data
- Violation history and resolution status
For a detailed explanation, visit our Methodology page.
Editorial Standards & Data Governance
WaterQ is an independent public-interest data project. Our mission is to demystify complex federal environmental compliance filings and provide everyday households with clear, actionable context on drinking water quality.
Fact-Checking & Sources
All health benchmarks, Maximum Contaminant Levels (MCLs), and toxicological summaries reference primary publications from the US EPA, CDC, WHO, and ANSI-accredited testing protocols (such as NSF International). We do not accept sponsored modifications of municipal ratings or contaminant assessments.
Data Integrity & Corrections
We maintain an active correction procedure. Municipal water authorities, utility directors, and residents are encouraged to submit updated laboratory results or dispute historical data records. Inquiries are investigated and addressed within 1–3 business days.
Report an error, submit recent lab results, or request an editorial review by emailing contact@waterq.us. You can inspect our mathematical formulas and scoring limitations on the Methodology page.
Contact
Have questions, feedback, or data correction requests? We'd love to hear from you.
Email: contact@waterq.us
Frequently Asked Questions
What is WaterQ and how does it work?
WaterQ summarizes selected EPA Safe Drinking Water Information System records. Scores appear only where a page can show supporting public water system records.
Where does WaterQ get its data?
WaterQ uses EPA Safe Drinking Water Information System compliance data. Our current public water system dataset is a selected subset, not every system in the United States.
How accurate is WaterQ data?
WaterQ reflects the EPA release last processed by this site. Federal records can lag local events; use your utility's latest Consumer Confidence Report and notices for current conditions.
Is WaterQ free to use?
Yes, WaterQ is completely free for users. We support the site through affiliate commissions on water filter and testing kit recommendations — see our affiliate disclosure. Recommendations are matched to your water system's actual detected contaminants, not to whichever product pays the highest commission.
Disclaimer
The information provided on WaterQ is for general informational purposes only and should not be considered medical or health advice. Water quality data is based on publicly available EPA records and may not reflect the most current conditions at any particular water system.
If you have specific concerns about your drinking water quality, please contact your local water utility or consult a qualified water quality professional. In case of a water emergency, follow guidance from your local health department.