Hard Water

Hard water is a very common problem, affecting water in more than 85% of the country. It is a result of the dissolved minerals calcium, magnesium and manganese. With an increase in these minerals, the following are seen (1):

While these are all unpleasant effects, hard water is not a hazard to human health and can be treated.

If you suspect that you have hard water, it can be tested. If you are connected to a public supply, call your water superintendent or city hall and ask if the water is hard. If you are on a private supply, collect a sample in an approved container and take it to a testing lab or send to your city or state health department for testing.

Water is considered hard when it exceeds 3 grains per gallon (GPG). A GPG is equvalent to 17.1 PPM, so if your water is 171 PPM, then your hardness is 10 GPG (2).

When results are returned to you and your water is found to be hard, there are a few options available to you. The most common way to soften water is through an ion exchange water softener. This system works by exchanging positively charged hardness minerals (calcium and magnesium) with positively charged softness minerals (sodium or potassium) on a resin surface that is regenerated. This exchange of minerals softens the water and can extend the life of plumbing systems since there is reduced clogging in the pipes. Residues, including soap scum and spotty dishes, should also diminish.

There are currently three basic types of ion transfer softeners. The first is an automatic softener. This type of softener is connected to a clock timer which at certain time intervals begins the regeneration process by flushing out the hard ions stuck to the resin and replacing them with the soft ions. This then allows for a continuous exchange of hard and soft ions throughout the day. The second type of softener is the demand initiated regeneration (DIR). With this system, regeneration occurs only when soft water has run out. Since this system adjusts to the amount of water used as opposed to the automatic type, it uses less salt and water and is more efficient. The final softener is a portable exchange. Here a tank is rented to the homeowner and has a regenerated resin. When the resin can no longer exchange ions, the tank is returned to the company and regenerated there (1,2).

To choose a system that will fit your needs, it is best to have representatives from different companies inspect your plumbing and give you an estimate. Next, ask your neighbors which companies they use and if they have any problems with their service. Contact the Better Business Bureau to see if the company you are choosing has had any customer service problems.


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  1. Water Quality Basics. A service of the Water Quality Association, Lisle, IL. http:www.wqa.org/WQIS/wqb-hardwater.html. (1996).
  2. "An Easy Way to Test", A service of Siouxland, an assembly of Midwestern organizations on the Internet. http://www.siouxlan.com/siouxlan/commercial/water/faq.html#tsO . (no date).

This page was prepared by S.L. Keyser, UCD EXTOXNET FAQ Team.
June 1997