Where to Discharge Water Softener Backwash + 3 Reuse Options

If you’re in the process of setting up a water softener and you want to know where to discharge water softener backwash, you’ll find all the answers you need in this guide.

We’ll be looking at what happens during the backwash process and why you need a water softener drain line, and the best places to discharge your water softener backwash.

📖 TL; DR

Looking for a quick answer? You can drain water softener discharge into the local sewage system, outside to the surface, the subsurface, or into your own onsite wastewater treatment system

🤔 Where Can you Discharge Water Softener Backwash?

Depending on what makes sense based on your geographical location and potential regulations set by your local municipality, there are several different options for discharging your water softener backwash.

These involve running the discharge into the ground, constructing your own homemade drainage solutions, or sending the discharge into your sewage pipe.

Let’s take a look at the best ways to discharge a water softener’s backwash:

Local Sewage System

The most convenient way to get rid of your water softener discharge is to send it directly into your local sewage system.

Before settling on this option, check your local municipality’s regulations to make sure you’re not restricted from draining water softener backwash into the raw sewage system. If sewage draining isn’t an option, consider one of the below alternatives.

water softener drain line

Dry Well

A dry well is a covered hole that is used to dispose of unwanted water. Traditionally made by burying a large container with holes in the side. Dry wells are deep and porous, so they offer a good means of quickly transferring excess water deep into the subsoil.

Ideally, locate your dry well above the water table. This will enable the well to slowly release water softener backwash into the ground, preventing a sudden spike in salt in the soil, which could harm the existing ecosystem.

Septic Drain Field

A septic drain field is a subsurface structure designed for wastewater disposal. This shallow, covered excavation offers a good way to disperse water softener discharge over a large surface area.

While septic drain fields are easy and affordable to use, your local authority may have regulations regarding discharging your water softener backwash in this manner due to potential ecological effects.

French Drain

A French drain is a trench dug in the ground that redirects water away from an area. A horizontal pipe placed along a ditch is covered with a layer of gravel and pebbles, and allows water softener backwash to be dispersed over a large area.

A French drain is one of the most affordable options for discharging the contents of your water softener drain line, but check your local regulations before installing this structure.

French drain

To the Surface

Discharging your water softener drain contents to the surface isn’t our most recommended option on this list because the brine could damage the vegetation around your property.

If sending brine discharge to the surface is one of your only options, make sure to do it safely, and keep the environment in mind.

You’ll need at least 100 feet of distance from the discharge point (the outlet pipe) to your property and any neighboring properties, and the discharge shouldn’t be near any waters or wetlands. Your well’s casing should be fully sealed to prevent ponding.

To the Subsurface

The subsurface is the layer beneath the earth’s surface.

You can drain your water softener backwash to the subsurface as long as you have a 100 meter distance between the brine discharge point and any nearby properties. For your safety, the discharge shouldn’t be uphill from any wells used for drinking water.

Sump Pump

For water softeners installed in an underground basement, a sump pump is the best way to eject backwash. Sump pumps send water up to a certain height, where it can then be drained in your preferred manner.

A good idea is to combine a sump pump and a dry well, but you could also divert the water into your sewage pipe.

Sump pump

Sewage Ejector Pump

A sewage ejector pump is similar to a sump pump, using water pressure to send backwash to a certain height. The bonus of this pump is that it sends discharge straight into the sewage water system, so it’s a good option if you want to connect your softener to your sewage line.

Into Your Own OWTS

Finally, you can send the contents of your water softener’s drain line to your own OWTS (onsite wastewater treatment system). The sewer system needs to be suitably sized to handle the water flow from the draining backwash.

To stop solids from getting into the leach field, you’ll most likely need to install an effluent screen at the outlet pipe of the septic tank. Due to its salt content, brine is heavy enough to settle at the bottom of the septic tank, so you’ll need to frequently pump the system.

🚰 How to Use a Water Softener’s Discharge

You don’t have to discharge your water softener’s backwash straight into the surrounding ground if you don’t want to. There are several ways to use water with high sodium concentrations around your property:

  • Weed killing: Salty water kills most vegetation, so if you’re embarking on a large-scale de-weeding project, consider using your water softener’s backwash as a natural weed-killer. Great places to use backwash water are your driveway and patio. Be careful if you plan to use the solution on your lawn or other green areas – the salt may kill your grass and plants that you didn’t intend to kill.
  • Deterring slugs: Salt dries slugs out, potentially killing them, so slugs stay away from salt as much as they can. Consider sprinkling salty water around the borders of your garden to prevent slugs from eating your plants.
  • De-icing surfaces: If you live in a region that’s prone to icy winters, you can save your water softener’s backwash for de-icing your driveways. Be careful not to use too much solution, though – softening salt can damage asphalt and concrete, and the water may freeze if you pour it over surfaces too liberally.
Killing weeds with water softener backwash

📥 How to Drain a Water Softening System

You may need to manually drain your water softening system before cleaning or performing maintenance. To drain the system, you have three options:

Regenerate the Softener

This is the option that’s physically the easiest, but technically the most challenging. Set your softener to perform a manual regeneration cycle, then skip the rest of the cycle once the brine tank is completely drained.

Scoop Out of Vacuum the Water

If you can’t regenerate your softening system, use a wet & dry vacuum to suck the water out of the tank, or scoop out the water with a bucket. This is a good option if you’re unable to lift the tank full of water yourself.

Pour the Water Into your Drain

Finally, the fastest option is to pour the water from the tank into a the drain. Set the softener to bypass, unhook the brine tank, and ask a friend to help you empty the water into a drain.

Draining a water softener brine tank

🧠 Where to Discharge Water Softener Backwash: FAQS

What does backwash contain?

The backwash from a water softener system contains a high concentration of sodium ions, a low concentration of calcium and magnesium minerals, and (depending on the quality of your water supply) potentially low levels of iron.

What’s the best way to discharge water softener backwash?

The best way to discharge water softener backwash is to simply connect the brine tank drain line to your local sewage system. Failing that, consider constructing your own drainage system, either with an old septic tank, a dry well, or a septic or French drain.

How much backwash does a water softener produce?

This depends on how frequently a water softener performs a regeneration cycle, which is based on factors including your water usage, the resin tank capacity, and the hardness of your water supply. The type of water softener also affects water softener drainage volume – a demand-initiated water softener discharges water less frequently than a time-based softener.

Where should your water softener’s drain line be?

The best location for a water softener drain line is about 1.5 inches above a floor drain, a drain standpipe, or a laundry sink rim.

Is it safe to discharge backwash into a sump basin?

Yes, it’s usually safe to discharge backwash into a sump basin. The sump pump will pump the backwash to above the level of the sump pit, allowing it to be drained into a pipe leading to your sewage line. However, the sump pump may become clogged with discharge water.

How can you discharge backwash from a basement up to ground level?

A sump pump or a sewage ejector pump will pump the backwash to the desired height from your basement. While a sump pump delivers water to your desired location, a sewage ejector pump is designed to send water straight into your sewage system.

Why shouldn’t you discharge your water softener system near water sources?

Salt is very difficult to separate from water. So, if your water softener waste line sends salty backwash water into your local drinking water well, you won’t be able to easily remove this salt with a standard water filter. You may end up drinking dangerously high quantities of sodium ions as a result.