Your result comes from public water data run by the USGS and the EPA. We match your ZIP code to your county. Then we show the hardness on record for that county. It is free, and it opens right on the page.

No. It is an estimate for your county, not a test of your own tap. The readings come from monitored water in your area. That can differ from what your utility sends. For your exact number, test your own water at home.

The USGS sorts water into four levels. They run from soft, to moderately hard, to hard, to very hard. Your result shows which level your county falls in. The harder it is, the more a softener helps.

You see your result with no signup at all. If you want the full sizing report, you can add your email. That is the only spot on the whole site where we ask. We do not set up an account for you.

The free result shows your hardness level and the county we used. The emailed report adds a size range for a softener. It also lists a few systems that fit your water. The size range is a general guide, not a home visit.

The public data is grouped by county, not by street. Some ZIP codes even sit across two counties. When that happens, we use the one that covers most of your ZIP. We always show you which county we used.

There are two ways. Enter your ZIP code here and we show the hardness on record for your county, free. Or buy a water hardness test kit or test strips and read your own tap. Only the kit measures the water in your house.

Not to start. The county number on this page is enough to point you at a size range. Buy a kit when you want the exact number for your tap. Buy one for certain if you are on a private well, because no utility is testing that water for you.

It is measured two ways. One is milligrams per litre, and the other is grains per gallon. One grain per gallon is 17.118 milligrams per litre. The USGS sorts the result into four levels, from soft to very hard. Softener makers size their tanks in grains, so grains per gallon is the number you shop with.