The number of homes in the United States with on-site septic systems is growing and one common concern for these homeowners is whether they can they can add a water softener to their system. This is an important question because the softening systems often affect the septic systems. If you have a septic system, is it safe to add a water softening system? If you do, what types of effects should you expect?
First, your septic plumbing is directed an underground storage tank. Wastewater is diverted into that tank and the heavier waste settles at the bottom. Within that tank, bacteria digest the waste, breaking solids into a liquid. The treated water then moves from the primary tank to a second tank and moves from there to a drainage field.
Second, a water softener replaces hard minerals, such as calcium and magnesium, with sodium or potassium ions. The water passes through ionized materials which need to be replaced from time to time. The removed minerals and excess salt from the sodium are washed into the drain.
With an understanding of these two processes, a primary concern is that the discharged sodium salts will be harmful to septic systems. This concern stems from the fact that high levels of sodium can impact bacteria. However, there haven’t been any scientific findings to suggest that the level of salt coming from the water softener will have a negative effect on the bacteria in a septic system.
Residential water softening systems generally go through between 40 and 70 gallons of water, and much of that water is fresh, without any salt. Ultimately, the water that does contain salt that makes it way into the septic system has become very dilute.
Additionally, some studies have shown that soft water can have a positive effect on septic systems. These studies have shown that the elevated sodium levels in water from water softeners is better suited to the growth of bacteria. The increased amount of water flowing into the septic tank moves at a slow enough rate that it does not overload the system. Finally, the soil in the drainage field benefits from the additional sodium.