In recent years several emerging non-chemical technologies based on a variety of physical phenomena have entered the market to aid consumers in addressing the problems caused by hard water.  These are an alternative to a traditional ion exchange water softener.  Generally these technologies do not remove most of the hardness minerals from the water, but reduce the problems associated by the hardness.  

If actual removal of calcium and magnesium (hardness minerals) or low concentrations of iron and manganese is desired, treatment such an ion exchange water softener must be used.  Water softeners work by exchanging sodium or potassium on the surface of a resin with calcium and magnesium in the water.  These types of softening will result in an increase in the concentration of sodium or potassium in the water.  More information on Ion Exchange Water Softeners can be found in NebGuide 1491 Drinking Water Treatment: Water Softening (Ion Exchange).  

In recent years several emerging non-chemical technologies based on a variety of physical phenomena have entered the market to aid consumers in addressing the problems caused by hard water.  These technologies generally use electricity, but at a rate lower than most home appliances.  These devices typically are designed to be installed at the point-of-entry, treating all water entering a residence or all water flowing to a hot water heater. The non-salt alternatives can be categorized as four different technologies, each are discussed below. 

Electrically induced precipitation uses a direct electrical current to precipitate water hardness and other compounds.  The hardness precipitate forms on an electrode that must be cleaned periodically.  Some studies have shown that precipitate forms a soft sludge on surfaces, such as a heating element, that is easily removable by fast flowing water near the surface.

Electrochemical water treatment systems induce the removal of dissolved hardness minerals and other contaminants using electricity. The technology goes by several names: continuous electrolytic deionization, capacitive deionization or electrically regenerated ion exchange. The introduction of a negatively charged electrode, or cathode, into the water will cause positively charged cations to move towards it.   

Template-assisted crystallization uses surface treated resin beads to convert (not remove) dissolved hardness ions to microscopic scale-resistant crystals.  The polymeric beads are fluidized creating agitation that releases the microscopic crystals and allows for further formation of crystals.  Once these crystals are formed and released from the beads, they are insoluble particles that will not form scale on surfaces.   

Magnetic water treatment, or the use of magnets and electromagnetic devices for water treatment, is a controversial method.  The approach is to pass the hard water through a magnetic field in order to form microscopic precipitates that do not form scale on water heaters, pipes, and other plumbing fixtures.   There is no scientific consensus as to the effectiveness of magnetic water treatment and as to its removal mechanisms.  Thus magnetic water treatment, unlike the other technologies described above, should be regarded as unproven technology. 

There is significant evidence in the literature that supports the application of some of these devices on industrial levels as an anti-scaling treatment.  Standardize testing procedures have not been developed for these devices, and these devices new to the residential market.  It is hard to predict which devices will work in all homes given the high degree of variability between homes in water quality and water use patterns. 

These no-salt technologies offer consumers some promise, but not without the problems that come with emerging technologies.  In some cases one of these products may be very effective, but in other cases a product may not live up to the consumer’s expectations. Thus, it is recommended that consumers should carefully investigate product claims prior to making a purchase of a specific device.

More information can be found in NebGuide G2275 Non-Salt Softening Alternatives.