Free TapChecked Tools
Calculators and lookups built on public water data and verified product specs — free, no email required. These are the same tools our reviews are built on: if a guide on this site quotes a number, one of these produced it, and you can re-run it yourself.
What’s In My Water? — ZIP Lookup
Enter your ZIP code to see your water system’s own EPA record: where its water comes from, its most recent lead and copper results, and any health-based violations — in plain English, with the source and retrieval date on the page. Built from EPA SDWIS data.
Softener Sizing Calculator
Household size, bathrooms and grains-per-gallon of hardness in — required grain capacity and the right size class out, with the math shown, including the iron and manganese adjustments and the salt-efficiency setting most sizing charts quietly skip.
5-Year True-Cost Calculator
Compare any two filters or softeners on total cost of ownership: purchase price, installation, replacement filters, and the water each system uses and wastes over five years. The number most review sites never show you.
New to all this? Start with how we check — or browse the water quality hub to learn what might be in your water in the first place.