New research by the School of Sustainable Engineering at Arizona State University has found that the hard water scaling normally found in the pipes of homes is an active environment for harmful bacterial growth. According to the U.S. Geological Survey nearly 90 percent of American homes have hard water - water containing high levels of calcium and magnesium.
The piping used in home plumbing, whether it is copper or PVC, has very smooth interior surfaces which dont permit bacteria to settle and grow. However, over time, hard water results in scale formation on the interior surfaces of those pipes and that provides a perfect home for bacteria. This can significantly increase exposure to pathogenic bacteria such as Legionella, which can cause Legionnaires disease.
The Arizona State University researchers found that the problem is not limited to hard scale formations. Soft scale, which is created with some forms of water conditioning, showed a similar tendency to support the growth of microbial films in the research.
The development of biofilms depends on a variety of factors such as water flow rates as well as the different plumbing materials. When pathogenic microbes inhabit these biofilms, home plumbing ends up being an ideal home with a direct line of contact with humans. Colonization of plumbing by disease-causing bacteria is well-documented, especially in hospital buildings and hotels.
Unless the minerals that cause scaling are entirely removed from the pipes people are at risk of bacterial infections, especially the elderly and those with a weak or compromised immune system, says Morton Satin, vice president of the Salt Institute. Once in the piping, the bacteria can be distributed through the showerheads as hot water and steam created are inhaled.
Only a salt based water softener can remove these minerals entirely by running the incoming hard water through a resin filter that traps the calcium and magnesium in the water -- as well as any iron, manganese or radium ions -- and replaces them with sodium ions.
Source: The Salt Institute