The most common water quality problem reported by consumers is hard water. A Geological Survey indicates that hard water is found in more than 85 percent of the country. So then, what makes water hard, and what can consumers do to treat this problem?
Because more than 60 percent of the earth's water is groundwater, it travels through rock and soil picking up minerals, including calcium and magnesium along the way. These two contaminants produce what is commonly referred to as 'hardness' in water. Generally speaking, hardness is measured in grains per gallon (gpg). For example, if a water test indicates a range of 1.0 to 3.5 gpg, the water is considered slightly hard. If the measurement is greater than 10.5 gpg, the water is rated as being very hard.
Hard water can be detected easily, even as one performs personal hygiene such as hair washing, or through the appearance of fixtures and appliances or changes in heating costs.
In areas where the water is hard or very hard, the local water utility may soften the water to about 5 or 6 gpg. This figure is still considered moderately hard, and consumers may still wish to soften the water further. The most common option for consumers is ion exchange water softening in the home. Domestic softening makes economic sense because it only softens the water to be used for laundering, cleaning, and other home uses. Softening at the central treatment facility is costly because it softens all water, including that which is used for fighting fires and cleaning streets.
There are many different types of softeners, each with its own benefits. The method used most often in homes is cation exchange, the principles of which are simple. An ion is an electrically charged atom or group of atoms. A cation is a positively charged ion. The water is softened when the hardness ions (magnesium and calcium) are exchanged for sodium ions. This exchange occurs in a resin bed during the softening cycle.
Three main parts make up most water softeners:
Many installed water softeners are fully automatic. An automatic unit regenerates according to a preset clock. For example, it might be set to regenerate every third night at 3am. Other systems may use an electronic sensor that regenerates the system according to water usage.
Size and Type Considerations
When water softeners were first manufactured, manual and semi-automatic models, where the regeneration process was started 'manually' by the homeowner, were the most common types sold. Today, the two main types on the market are automatic and demand-initiated regeneration (DIR) water softeners. Automatic softeners regenerate on a schedule regulated by a timer. DIR softeners are the most sophisticated, containing a hardness sensor or water meter which triggers regeneration as needed.
There are several factors that a person must take into consideration before purchasing a softener, including the number of people in the home, how much water is used, and the hardness of the water.
Determining the size of the softener, knowing these factors, is rather simple. Multiply 75 (average gallons per day used per person) by the number of people in your household. For example, four people in a household will likely use 300 gallons of water per day. Multiply the 300 gallons per day by the number of grains per gallon of hardness present in your water. Continuing the example, 300 gallons per day times 20 gpg gives a figure of 6000 grains of hardness per day that would require removal. Given a typical regeneration capacity of 18.000 to 30,000 grains per regeneration, a softening system in this case would optimally be regenerated every three to five days.
The Sodium Issue
For some consumers, the fact that sodium is used to soften water raises a concern about their drinking water and a potential health risk. However, what many people may not know is that when doctors and researchers discuss salt and its effects on a person's health, they usually refer to sodium chloride, and not sodium bicarbonate which is the result of softening.
Further, according to Dr. Andrew Zeifer, Director of the Hypertension Clinic at the University of Michigan, 'Drinking water represents a very small part of sodium intake in most persons. Even water softening systems using salt don't introduce enough salt to be of concern.' Similar view were expressed in the New England Journal of Medicine, and by the U.S. Environmental Protection Agency.
If consumers do not want to add any additional sodium to their diet, or if they are on a medically prescribed diet, they may choose to connect their water softener to the hot water line only, thus leaving consumers able to drink and cook with unsoftened cold water. Another option would be to install a reverse osmosis or distillation system, and have the full benefits of both technologies in their home.
Benefits of Softened Water
Even for those whose water is slightly hard, significant benefits can result from using softened water: