Testing for hard water

Or how hard is your hard water?
The severity of hardness is measured by grains (of mineral) per gallon (GPG) or, in some cases, by parts per million (PPM). These two measurements are related: 17.1 PPM equals 1 GPG. Technically, any water that contains more than 1 GPG of dissolved hardness minerals is considered hard, but realistically, water with from 0 to 3.5 GPG is relatively soft. Water with more than 10.5 GPG is very hard. Between those extremes is typical, moderately hard water.

If you have public water, call the city offices or the Superintendent of Water and ask for the test results. If they quote the quantities of various minerals in parts per million (PPM), you can easily work out the conversion of PPM to GPG by dividing the quantity of PPM by 17.1.

If your water is supplied privately, you'll probably have to test for hardness. In some areas, city or county health departments offer testing. If yours doesn't, you can have it tested by an independent water-testing lab or a water conditioning company, but be advised that the latter has a stake in the outcome and may offer free testing as a come-on for selling you equipment you may not need. Many softener companies will hard-water test a mailed-in sample for free; some will send you a do-it-yourself test strip kit.

You can ask your water utility or the state health department for names of independent testing labs, or look under "Laboratories" in the Yellow Pages. They supply you with a sample kit that you return by mail.