According to the American Heart Association, fatal heart attacks are more common in areas where the water is either naturally soft or has been treated to remove calcium and magnesium.
The AHA also indicated some other health problems, including goiters and bladder disease, may be tied to consumption of salt-softened water.
Authorities on water treatment point out that it is possible to condition water without using salt. Water conditioners that do not use salt are totally safe from a health point of view, as well as being environmentally sound.
In Regina, Saskatchewan, that city's medical health officer in April cautioned the city government that "softened water could result in levels of sodium which are undesirable for persons with certain medical conditions requiring restricted sodium intakes." As a result Regina is considering action to restrict the use of salt-softened water.. Some authorities have said that the problem is not limited to drinking water, but also to absorption of salt through the skin when bathing.
With most water softeners that use salt, calcium and magnesium are removed and replaced with sodium. Sodium has been linked to high blood pressure and hypertension. According to Dr. Martin Fox's book, Healthy Water for a Longer Life, an adult who takes a 15-minute bath typically absorbs almost twice as much water - and the chemicals dissolved in it- as he or she gets in a day's drinking water.
The World Health Organization's report NUTRIENTS IN DRINKING WATER links increased mortality from Cardiovascular Disease in softened water. In addition, many contributing experts recommend hard water over softened water for household use.