How Water Softeners Impact Septic Systems

What Is A Water Softener?

A water softener is a fairly simple system that treats hard water. This system has two primary components: a softener tank and a brine tank. 
As water passes through the softener tank, the positively charged minerals such as calcium, magnesium, iron, and sodium attach to the negatively charged tank. The softened water then continues through the plumbing system and is distributed throughout your building.
Every three to four days, the water softener draws salt water from the brine tank to negatively charge the softener tank and release the positively charged minerals. As the minerals are released, they are flushed out of the system through the plumbing system. In your case, they would flush through the septic system.

The Impact on Your Septic System

There are two septic tank issues that result from water softeners: system overload and clogging.
The flushing process that happens once to twice a week uses between 50 to 150 gallons of brine solution (salt water). That is the equivalent of several showers. The sudden influx of water can overwhelm the septic system, especially if the release occurs when your laundry machine or dishwasher is running. The result can be water or sewage backups, or an overwhelmed drain field.
Secondly, the salt water is particularly harmful for the septic system because salt water is significantly heavier than fresh water. When the salt water enters the septic tank, it will rapidly sink to the bottom, sometimes even lifting the sludge and suspending it in the effluent along with the scum layer. This can allow sludge to flow out into the drain field, causing clogs in the pipes and foul odors in the field.

A Solution

Most homes that rely on a septic system also rely on private water wells to supply the building with water. This water supply tends to contain high mineral content which calls for a water softener. So, we cannot tell you not to install a water softener. Rather, we recommend that the water softener is installed to discharge outside of the plumbing system. This can be into the storm drain or downspout.