The Water Quality Research Foundation (WQRF) initiated a study which was conducted by the Battelle Institute to test devices fed with softened and unsoftened water under controlled laboratory conditions designed to accelerate the waterside scaling in Water Heaters, dishwashers, washing machines and other water using appliances and quantify the performance efficiency.
In addition to testing these major home appliances, they also tested shower heads and other water fixtures to quantify the effects of hard water on their performance.
Ten low flow shower heads were installed on the hot water supply coming from the ten instantaneous gas water heaters; five were tested on unsoftened water and five were tested using softened water. These shower heads were tested for a total of seven days. At the end of the test, the shower heads using softened well water were performing nearly as well as the day they were installed. However, the shower heads using unsoftened well water had over three-fourths of their nozzles clogged at the end of the test.
After the tests with the shower heads were completed, ten low flow faucets were installed on the hot water supply coming from the ten instantaneous gas water heaters. Five low flow faucets were tested using unsoftened well water (26 grains per gallon), and five low flow faucets were tested using softened well water (0.55 grains per gallon). The low flow faucets on softened well water are relatively clean and continued to operate without problems over the period of the test. The low flow faucets on unsoftened well water showed large amounts of scale collection on the strainers, and were stopped after 19 equivalent days of testing because the specified flow rate of 1.25 gallons per minute could no longer be maintained.
At the end of the test, the faucets using softened well water were performing nearly as well as the day they were installed. However, the strainers on the faucets using unsoftened well water were almost completely clogged.
The collection of scale on the faucets using unsoftened water appears to be the result of scale breaking loose from upstream portions of the plumbing and being trapped in the strainers. Prior to installing the faucets, the instantaneous water heaters on unsoftened water had logged the equivalent of 1.6 years of hot water flow and the piping system appears to be coated with scale buildup. The instantaneous water heaters on softened well water had logged the equivalent of 2.0 years of hot water flow and yet the faucets on these heaters showed almost no scale collection on the strainers.
Shower heads using soft water maintained a brilliant luster, full flow and performed well throughout the study; nearly as well as the day they were installed. While shower heads on hard water lost 75% of the flow rate in less than 18 months of use.
Low Flow Faucets on hard water could not maintain the specified 1.25 gallons per minute flow rate because of scale collection within the strainers. The strainers on the faucets using hard water were almost completely plugged after 19 equivalent days of testing.