In studies conducted by scientists in the late 1970’s at the University of Wisconsin, it was confirmed that salt-brine discharge from water softeners caused no problems in the operation of typical anaerobic or newer style aerobic home treatment plant. It was also determined that water softener regeneration waste did not interfere with drain field soil percolation but actually could, under some circumstances improve soil percolation particularly in fine-textured soil. The important and beneficial difference is that septic tank effluents containing water softener effluents contain significant amounts of calcium and magnesium, which counteract the effect of sodium and help maintain and sustain soil permeability. The studies concluded that it is better to discharge water softener waste to septic systems than to separate dry wells or ditches. Click here to view the CMHC Water Softener Fact Sheet.