Most people don’t think about their water until there is a problem. Unfortunately, the chemical composition of your water can damage appliances and fixtures in your home which can add up to hundreds or even thousands of dollars in replacement costs. According to the U.S. Geological Survey, 85 percent of American homes have problems with hard water.
Hardness is a term used to describe water that contains dissolved minerals. Hard water comes from underground sources that collect dissolved minerals from rock like calcium, magnesium carbonate, and manganese. The measurement for hardness is in terms of parts per million or grains per gallon are the most common. One part per million (PPM) is just what it says: out of one million units, one unit. Grains, or grains per gallon (GPG) is a weight measurement taken from the Egyptians; one dry grain of wheat, or about 1/7000 of a pound. It takes 17.1 PPM to equal 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.
Source: http://ga.water.usgs.gov/edu/characteristics.html
Hardness is a concern as it pertains to bathing, washing dishes and clothes, and shaving, washing your car and many other uses of water; hard water is not as efficient or convenient as "soft water". You use only half as much soap cleaning with soft water. Hard water and soap combine to form "soap scum" that can’t be rinsed off, forming a ‘bathtub ring’ on all surfaces, and dries leaving unsightly spots on your dishes.
When hard water is heated, the minerals are re-crystallized to form scale. This scale can plug your pipes and hot water heater, causing premature failure, and costly replacement. The soap scum remains on your skin even after rinsing, clogging the pores of your skin and coating every hair on your body. This material can serve as a home for bacteria, causing diaper rash, minor skin irritation and skin that continually itches. When heated, dissolved hard-water minerals also re-crystallize and form scale that eventually clogs plumbing. Eventually, this reduces water flow through pipes.
Mineral deposits adversely affect other water-heating appliances such as dishwashers and coffee makers, increasing the need for repairs. Scale builds up onto interior surfaces of water heaters, making them less efficient and more likely to fail.
According to a study at New Mexico State University, commissioned by the Water Quality Research Council, water heaters operate from 22 percent to 30 percent less efficiently when plagued with hard water scale.
How Water Softeners Work
A whole-house water softener works by exchanging ions from sodium chloride (salt) and a resin which is known as “cation exchange.” Cations are positively charged ions. Inside a cation-exchange softener, the house water supply flows through plastic-like beads called “resin,” which are arranged in columns, called beds, which reside in the resin tank. The ions from the dissolved salt are attracted to the resin, most commonly sodium zeolite, and are released when heavier particles such as calcium, magnesium, and iron flow through the resin.
In 1905, a German chemist used synthetic aluminosilicate materials known as zeolites in the first ion exchange water softeners. Although aluminosilicate materials are rarely used today, the term "zeolite softener" is commonly used to describe any cation exchange process. In the middle 1940’s, ion exchange resins were developed based on the copolymerization of styrene cross-linked with divinylbenzene. These polystyrene-divinylbenzene resins were very stable and had much greater exchange capacities than their predecessors, and similar materials are still in use today. (http://www.gewater.com/handbook/ext_treatment/ch_8_ionexchange.jsp )
The beads must be flushed with water to remove the minerals and replenish the resin bed with sodium ions. This usually occurs once a day and is controlled by a timer which energizes a solenoid valve to flush the resin with new salt water and discharge the mineral-laden water to a drain. Then the cycle repeats.
Usually the only maintenance that is required is to add rock salt to the brine tank after lifting the lid and checking how much salt is inside. Some systems use enclosed canister units which are filled with different materials that must be replaced.
Buying a Water Softener
Single tank water softeners are still common, but while the resin is recharging, the water will be shut off to the house. This typically occurs at night so it not a problem. There are also dual-tank systems where one tank remains in use while the other is being recharged. Obviously, these units are more expensive. A typical water softener can range from about $1,000 to $2,000.
Many contractors that install water softeners will provide a service where they regularly exchange exhausted with charged units. Due to the increased salt levels in the discharge water, check with your local municipality to determine if sodium is considered a pollutant. Some towns recycle wastewater to water open spaces or other non-potable uses.
When selecting a water softener, look for features such as NSF certification and an extended warranty on the control valve and mineral tank, such as three years for the valve and 10 years for the mineral tank. A good quality water softener should last 20 years and save you thousands of dollars in increased water heating efficiency and savings on soaps and detergents.
