If your home is one of the 85 percent of American homes with hard water, you may be considering installing a water softener. There are advantages and disadvantages of water softeners to consider, but if your home is on a septic system an additional consideration should be whether the water softener will cause any problems with the septic system.
There have been several studies done with no consensus reached as to whether a water softener or water conditioner can be used without damaging a septic system. As an initial matter, there are a few areas where local building codes prohibit the use of water softeners with septic systems so check to be sure that you even have the option to install a water softener in your area.
During normal operation, water softeners periodically discharge large volumes of water with high levels of sodium which raises concerns about the possibility of overloading the septic system with too much water and also about the effect of the sodium on the septic tank and septic field.
Water softeners discharge about 50 to 70 gallons of water during a “regeneration cycle” which occurs two to three times a week. The concern is that too much water flowing into the septic tank will cause the effluent to flow to the drain field before the solid material has had a chance to settle out. Also, that much water could stir up the effluent and cause too much solid material to flow into the drain field.
By comparison, a typical washing machine uses about 40 to 55 gallons of water per load so the effect of a water softener is similar to doing one and a half loads of laundry three times a week. A healthy septic system that is not already nearly overloaded should be able to handle this additional volume of water.
The septic tank and drain field depend on millions of naturally occurring bacteria to treat the waste water. Studies on the effect of the additional sodium from a water softener have not found any reason to conclude that the added sodium is harmful to the bacteria in a septic system.
