Will Your Water Softening System Ruin Your Septic?

If you have hard water, you know how damaging it can be–from making your laundry dingy, to causing mineral build-up on your sink and shower fixtures, to significantly reducing the lifespan of your water-using appliances. But will your water softening system ruin your septic?

In this month’s Secondwind blog, we discuss this question. But before we begin our discussion, let’s talk about what’s involved in the water softening process.

Removing Hard Water

Hard water is softened by removing the calcium and magnesium ions contained in it. This is done through the installation of a water treatment system. When hard water passes through the system’s resin bed, the calcium and magnesium ions are removed, so only softened water flows into your home. During the softening cycle, the sodium (salt) in the resin bed is exchanged for hard water minerals. Once the resin bed is filled up with calcium and magnesium ions, it is regenerated (cleaned) so it can continue attracting and collecting hard water minerals.

Here are some common questions people ask about water softening and septic systems:

Is salt resin toxic to your septic tank’s bacteria?

Your septic tank contains natural bacteria that decomposes waste, turning it into a water and sludge residue. After further treatment, it is discharged into the soil.

Can the increased salt levels in your softened water hurt these bacterial organisms?

NO. According to a University of Wisconsin and National Sanitary Foundation study, the added salt does not affect the soil’s ability to absorb water. In fact, it can be helpful to the bacterial organisms in your septic system.

Does the volume of backwash during the regeneration cycle upset your septic tank’s “digestion” process, carrying solids into your leach field?

No. Studies have shown that the volume of softener backwash during regeneration does not impact your septic tank’s “digestion” process.

Will the salt from the resin bed cause some soils to swell and reduce the water percolation rate?

No. The backwash will not affect the percolation rate, or the rate at which clean water disperses into the soil. In fact, if you have clay soil, the calcium-rich backwash from your resin bed can actually improve its permeability and percolation rate.  

There is a great deal of controversy across the nation surrounding the topic of water softener regeneration and septic systems.  Although study after study has shown no deleterious effect, the beliefs persist.  After speaking with many septic designers and installers in this region, plus water professionals at the State Department of Environmental Services, we have some thoughts to share with you.

It certainly does make sense to install the most efficient water softener possible.  Efficiency in water softeners is measured in amount of salt required to exchange a certain number of grains of hardness.  Not all softeners are alike. To get the best efficiency, choose a softener with “demand initiated regeneration” which only cleans when it needs to based on gallons used rather than time.  This will save many pounds of salt and gallons of water from going into your septic system.

Some of the problems that are occasionally attributed to water softener or filter backwash are simply a result of additional water volume going to the septic from the regeneration of the system.  If you have problem water you may have water treatment that needs to frequently regenerate.  If the septic system has some extra capacity,  this won’t be a problem.  But if your system is already operating at capacity due to the number of people in the home, this could present a problem.  Builders will often ask for a septic system to be designed for one extra bedroom to allow for this extra water volume.

If you have a septic system that is already operating to capacity or if you are concerned about any impact, we can work with you to find an alternative location for the draining of your backwash water.

Hard Water Treatment Systems in NH

Everyone deserves to have clean, safe, quality water. If you have questions about the quality of your home’s water or suspect that you have a hard water problem, contact the water treatment professionals at Secondwind Water Systems. We will gladly provide a free water analysis and suggest a water treatment solution that is best for your home and budget.