Our Mission
Accurate, free water hardness data for every household in the United States.
Why WaterHardness.org Exists
Hard water affects more than 85% of American homes, yet finding reliable hardness data for your specific location has always been surprisingly difficult. Utility Consumer Confidence Reports are published annually but they're scattered across thousands of individual water systems, often buried in PDFs, and rarely standardized.
We built WaterHardness.org to solve that. Our goal is to give every US household a fast, free way to look up their water hardness—no sign-ups, no paywalls, no sales pitches. Whether you're deciding if you need a water softener, diagnosing hard water symptoms, or just curious, this site is for you.
Where Our Data Comes From
We combine multiple federal and state data sources to produce the most complete picture of water hardness across the US:
- EPA SDWIS — The Safe Drinking Water Information System catalogs ~48,000 active community water systems, including the areas they serve.
- USGS Water Quality Portal — Millions of water quality measurements from wells, streams, and monitoring stations across every state.
- State Compliance Labs — Treated water lab results from state agencies (California EDT, Michigan DEQ) that reflect what actually comes out of the tap.
- Consumer Confidence Reports — Annual water quality reports published by utilities. We hand-verify CCR data for hundreds of cities with 50,000+ residents.
Help Us Improve
Have your utility's CCR or local water test results? Notice an error? We rely on community contributions to keep our data accurate. Send us your data and we'll verify and incorporate it.
How We Keep This Free
WaterHardness.org is free to use and always will be. We earn a small commission when you purchase water treatment products through our recommendation links. Every product we recommend is independently researched - we only suggest products we believe in, and our recommendations are never influenced by commission rates.
This revenue covers our hosting, data processing, and ongoing data verification work. We believe transparency about monetization builds trust, and trust is what makes this resource useful.
Disclaimer
Water hardness values on this site are estimates based on publicly available data from the EPA, USGS, state agencies, and utility reports. Actual tap water hardness may differ due to seasonal variation, treatment changes, or local distribution factors. For precise results, test your water directly with a certified lab or home test kit. This site is for informational purposes only and does not constitute professional advice.