How Hard Should Water Be Before I Consider A Water Softener?

We are moving into a new house and my wife was told the water is “hard”.  The local water utility says the water is not very hard and they don’t recommend treatment.  How hard is too hard?  The water hardness varies but it is around 170 ppm they say.  What is water hardness anyway, rocks in the water?


Bill T
Nashville TN


Bill –   The term "water hardness" originally referred to the ability of water to precipitate soap and form soap scum. Soap is precipitated (or brought to the "surface") by water containing high levels of calcium and magnesium. The "harder" the water the less soap will dissolve in the water.

In current practice, total hardness is defined as the sum of the concentration of the calcium and magnesium ions, expressed as calcium carbonate. Hardness can be expressed as calcium carbonate in either parts per million (the same as milligrams per liter) or grains per gallon.

Since automatic water softeners are rated in grains of hardness removal, this is the more common measurement used by U.S. consumers. One grain of hardness equals approximately 17.1 ppm of calcium carbonate hardness.

For your water, 170 PPM is the same as saying the water has 10 grains per gallon of hardness.   This is moderately hard but not extremely hard water.  You may expect to see some white scale building up on fixtures, but many homeowners live with 10 grain per gallon water with no problems.

Water hardness minerals are commonly treated with a water softener system that uses an ion-exchange resin and regenerates with salt. For residential and commercial applications these are the most effective as they actually remove the hardness minerals from water.

Softened water saves money by reducing the amount of detergent required for laundry and bathing, and by lowering the amount of energy required in electric and gas water heaters.  Soft water leaves skin and hair softer and eliminates the drying effects of hard water minerals on skin and hair.  Soft or conditioned water also stops mineral scales from forming in pipes and extends the life of fixtures, appliances and water heaters.



How Hard is Too Hard?

Natural waters may range from close to zero hardness to many hundreds of parts per million. In our experience, water over 100 or 150 ppm (approximately 8 - 10 grains/gallon) is hard enough to warrant water softening. When the water hardness exceeds 250 - 300 ppm, a water softener becomes somewhat of a necessity, as piping systems, water heaters, fixtures and appliances become scaled up and worn out prematurely. At levels of 100 to 250 ppm (or up to 8 to about 15 grains/ gallon) water softening is an aesthetic improvement, reducing spotting of fixtures and surfaces, and making hair and skin softer.


Water Softener Alternatives

There are many devices on the market that claim to eliminate the effects of water hardness by the use of electrical fields, magnetism, or catalytic metals. These are sometimes referred to as “no salt water conditioners”, “no salt water softeners”, “salt free water softeners” and “water conditioners”.   We have many customers using these and they say they are happy with the results.  Generally if the water is over 20 grains per gallon though, we recommend a standard salt-efficient flow-meter regenerating water softener.