What's in your water, and what should you do about it?
Look up your utility's EPA records, then size a softener, compare filters or care for your well, with every formula and source shown.
- EPA records for lead, PFAS and violations
- Formulas shown, sources cited
- Free, no sign-up
Calculators by topic
- Drinking waterCompare filters, bottled water and reverse osmosis, and find which certifications matter for lead and PFAS.
- Hardness & softeningConvert hardness units, size a water softener and estimate what salt will cost you each year.
- Private wellsShock-chlorinate a well safely, size a pressure tank and estimate the pump you need.
- Water quality lookupViolations, lead and PFAS sampling and hardness for your public water system.
- Water by state and countyLocal pages for 200 of the most populous U.S. counties.
Popular calculators
Why trust these numbers
Formulas in the open
Every calculator shows its formula and the assumptions behind each default.
Cited, checked sources
Defaults come from EPA, CDC, USGS, NSF, university extension services and manufacturer specs, each linked.
Calm and careful
We explain what EPA data does and doesn't mean. A detection isn't a violation. How we calculate