Study Suggests Softeners Do Not Hurt Septic Tank Performance

Independent testing concludes that systems can work well together

Water softeners Septic Tanks Water Quality Assn.

Water softeners set with appropriate salt efficiency do not harm septic systems and may actually help them, according to a new study released at WQA Aquatech USA 2013.

The Water Quality Research Foundation commissioned Virginia Polytechnic Institute and State University to conduct independent and scientific testing on the issue in 2012. The result is an official report, "Changes in Septic Tank Effluent Due to Water Softener Use." Nearly $100,000 was invested in this 18-month study, which included many site visits and the work of numerous trained experts from the Water Quality Assn. (WQA), the National Onsite Wastewater Recycling Assn. (NOWRA), regulators and NSF Intl.

According to the authors of the study, "The data indicate that the use of efficiently operated water softeners improves septic tank performance, while the use of very inefficient home softeners may have a negative effect on solids discharge to the drain field and the level of impact will depend on the level of hardness in the water, whether the regeneration waste is discharged to the septic tank, and the amount of excess sodium present in regeneration wastes."

Softeners are often the enabling technology that keeps the rest of our houses running effectively by preventing damaging scale build up, said Dave Haataja, executive director of WQA. In areas with especially hard water, softeners are a necessity for anyone who does not want to constantly buy new appliances and replace pipes and fixtures. Comprehensive independent studies also have shown many other practical advantages: saving energy and money, reducing the use of detergents and keeping landfills a little less full.

To obtain the most accurate results possible, two different approaches were taken in the research. One study in a controlled laboratory setting examined a range of softener/septic reactions. Then, to look at real-world conditions in everyday circumstances, case studies were conducted in the field. The authors also looked at previous studies and tests.

WQA and NOWRA have collaborated to update the "Guidance for the Use of Water Softening and Onsite Wastewater Treatment Equipment" to include recommendations for use of water softeners with higher salt efficiencies, which this study indicates will minimize potential impacts on septic tank performance.

Water Quality Assn.

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