Hard Water
It's the amount of minerals, calcium carbonate and magnesium carbonate in your water.  We could even get more technical, but you'll know water hardness as it causes scaling of pipes, fittings, valves, fixtures and appliances.  It also forms unpleasant deposits on clothing, dishes and crystal - requiring additional soap usage.  Mineral build-up in hot water heaters, as well as other water-using appliances, results in increased energy cost and shortened appliance life. 

Hard Cash
The most common measurement for hardness in the U.S. is grains per gallon (gpg).  The EPA recommendation is a maximum of 7 grains hard.  Treated water can increase the useful life of plumbing and water-using appliances up to 30%.  Also, more energy is needed to heat hard water.  If the scale is only 1/8" thick, 33% more fuel is required.  More soft water means more hard cash for you.

• Soft Water is 1.0 grain per gallon or less
• Slightly Hard Water is 1.0 to 3.5 grains per gallon
• Moderately Hard Water is 3.5 to 7.0 grains per gallon
• Hard Water is 7.0 or more grains per gallon

Who Needs Water Treatment?  Most Of Us.
From the standards above, it is easy to see how most households (well or city water) would benefit from water treatment.   Although water problems may vary from home to home depending on the water source and other factors, for most residential and commercial applications, it is desirable to soften and filter the water.    For example, clothes washed in soft water lasts up to 33% longer.  Take a person's clothing replacement estimate; multiply it by .33 and the answer equals how much a single person can save on clothing alone.