9 Easy Water Softener Drain Line Options [In- & Outdoors]

Finding the right drainage solution for your water softener system can be a daunting task. The shear volume and high concentrations of sodium chloride and other minerals make it so that not every solution is viable.

Furthermore, the size and type of hose or piping you use and the way your drain line is installed are critical to avoid any problems during the systems' lifetime.

Let's have a look into what to do and what to avoid when choosing the right drain solution for your water softener!

Why Does A Water Softener Need A Drain?

A conventional water softener uses ion exchange to replace calcium and magnesium ions within hard water with sodium ions. To keep this process going the system periodically needs to be 'recharged' by flushing it with excess amounts of sodium.

Every time your water softener system regenerates you are left with tens of gallons of water containing a high sodium concentration, along with the previously removed calcium and magnesium ions.

Using the right settings for your system will assure it regenerates only when it needs to thereby keeping the amount of discharge to a minimum.

Nonetheless, to get rid of this backwash your water softener system will need a drain, however, as the salt concentration within this backwash is so high some considerations should be taken into account when picking a drainage option for your system.

Water Softener Overflow

Some water softener systems also have an overflow drain, this allows any excess water to drain from your systems' brine tank when something go wrong, for example when it gets clogged due to salt mushing.

As this is just an overflow it can only be drained assisted by gravity, it is therefor important to never position the end of your overflow drain line above or close to the same level as its origin point.

How Can You Drain Your Water Softener?

The most convenient way of getting rid of the water softener backwash from your brine tank is to attach it straight to your local sewage system.

However, in some remote areas, a direct connection to the sewer system might not be available and even if there is, some municipalities have restrictions concerning discharging water softener backwash directly into the sewer system.

Therefor, before choosing a type of drain, it is best to consult the local rules and regulations regarding the discharge of water softener backwash. These rules can influence which water softener is best for you and even the type of salt you use in your system.

Regardless of the type of drain you end up using you will need to ensure an air gap when installing your drain line.

Why Does Your Water Softener Drain Line Need An Air Gap?

The Minnesota Plumbing Code states:

4714.611.2 Airgap Discharge. Any discharge from water conditioning equipment shall enter the drainage system through an airgap in accordance with Table 603.3.1 or an airgap device in accordance with Table 603.2, NSF 58, or IAPMO PS 65.

And for a good reason! Not doing so could lead to contamination of your water supply.

During cases of extremely high water demand, it is possible for negative pressure to exist within your plumbing, this can lead to suction in your water softener system thereby causing flow back through your drain line into your system.

Once in your water softener any contaminants in this backflow will start to cross contaminate your water supply.

To avoid any contaminants from entering your water supply and assure your house and its residents with a clean supply of water, the plumbing code states your water softeners' drain line should ensure an air gap separation of at least twice the diameter of the hose and no less than one and a half inches above the receptacle.

A properly installed air gapped drain includes rigid mounting of the drain line to avoid any immersion of the tube in, or spray from, environmental contaminants, thus preventing any cross connection between your water supply and other waste water downstream.

With an air gap installed, any water past that point will only be able to flow out through the waste line, this prevents any contaminated drain water from flowing back into your system thereby contaminating your water supply.

How Long Can A Drain Line Be?

Although from a technical aspect there is no real limit to the length of your systems drain line except perhaps your local water pressure, a longer tube comes with all sorts of risks like damage or blockage of the flow. It is therefore best to keep the distance between your system and an air gap as short as possible.

Generally anything under 30 feet should pose no problems when draining your system, if your drain line needs to be longer you might want to consider using wider tubing to ensure proper draining.

Furthermore, the longer your drain line the higher the probability it will contain standing water over prolonged periods, in hotter or colder climates this increases the chance of problems arising.

Similar to the risk of salt bridging, in warmer climates, this standing water can cause problems as the high mineral concentrations in the discharge start to crystallize due to evaporation. These crystallized minerals could over time clog your water softener drain, causing all kinds of problems.

Next to crystallization another risk of standing water in warmer climates is that it promotes bacterial and algae growth. Although most of these organisms are harmless to your health they could also eventually block the flow through your drain line.

For colder climates a longer tube, especially one that goes outside, is at risk of freezing.

If temperatures around your water softer drop below freezing during winter be sure to properly winterize your system to avoid any problems.

Hard Tubing vs Soft Tubing

For the best performing drain line over time hard tubing is the way to go, although more of a hassle upon initial installation it can avoid a lot of problems down the line.

Because the life expectancy of modern water softeners can be up to 20 years it can outlive your drain line tubing. Soft tubing over time will start to lose it regular round form and start to become flat, this can severely reduce the amount of water that can flow through it.

Furthermore, soft tubing is at a risk of getting pinched either between or beneath a heavy object causing your line to be blocked or get damaged, in both situations either the performance of your system will suffer or the room containing your water softener could be flooded with gallons of water softener discharge.

What Happens If Your Drain Line Gets Clogged

In the best scenario a blockage in your water softeners' drain line will be detected by the system causing it to stop regenerating its resin matrix. This will lead your systems' performance to decline over time until it completely stops working.

In the worst scenario your system will keep discharging causing pressure to build in your system until it 'explodes' and your home is flooded with gallons of water softener backwash.

Most Convenient Water Softener Discharge Drain Options

If your local municipality allows for it the easiest way to get rid of your water softeners discharge is by draining it into your local sewage system. This is easily achieved with the following methods.

Caution: Before implementing any of the solutions below, be sure to consult local authorities for any rules and regulations around draining water softener discharge into your local sewage system!

Utility Sink

Most water softener systems are installed in or near a laundry room or kitchen. Any nearby laundry or utility sink can provide the perfect solution for your drain line.

Simply firmly attach the hose above sink, making sure it cannot come in contact with any water in or spray form the sink.

When using this solution ensure the sink is always open (no stopper) and provides enough flow through to get rid of the discharge without overflowing.

Floor Drain

Floor drains nearby your water softener can provide an easy solution for your drain line, as well as the optional overflow drain, on your system.

Ensuring an air gap between the floor drain and your drain line can be tricky however pre-build air gaps for floor drains are available.

One thing to keep in mind is that floor drains are often located in the middle of a room, and it might not be optimal to have hoses across your floor, besides being inconvenient it also increases the risk of damaging the drain lines thereby allowing for contamination.

To avoid this you might want to consider using a nearby sink or creating a connection to your waste stack pipe.

Waste Stack Pipe

If there is no sink or floor drain nearby you might have to create a branch in your waste drain pipe and attach your drain line.

Make sure to use an appropriate air gap and not just push the line into the drain pipe as you wouldn't want anything from the sewer line contaminating your water supply.

Be sure to install a so called P-trap to prevent sewer odors and gases from entering your house.

Can A Water Softener Drain Uphill

Because your water softener drain runs on water pressure it is possible to drain your system into a sewer line overhead or for example out of a basement.

Most water softener systems can use the water pressure to allow for a drainpipe to elevate up to 8 feet above the floor that houses the system.

Best Backwash Drain Options In The Basement Or Crawlspace

Anything under 8 feet in height difference could possibly be drained by running a drain line upstairs to a nearby sink or floor drain.

However, if your systems' drain isn't assisted by water pressure the height difference is too great, there are options to use pumps that can overcome greater height differences.

Use caution when selecting a pumping system as, because of the high salt concentration, brine can be very corrosive. To extend the lifetime of your pump make sure that if the pump is submerged in standing water for prolonged periods it is regularly rinsed with water without any salt in it. Alternatively, stainless steel or plastic pumps are available.

Regardless of which type of pump you use, be sure to install an air gap between the drain pipe and the pump basin.

Sewage Ejector Pump

One way transport water softener discharge up higher elevations is using a sewage ejector pump.

A sewage ejector is attached to the sewage system through a vent that blocks any raw sewage from streaming back into your drain line and vents any gases that are produced within the piping.

Some sewage ejector pumps also contain a small spinning blade that allows for small waste particles to be cut up and pump through, this makes them suitable for all kinds of waste disposal like under a sink or attached to a toilet.

Because big pumps can be expensive it can be beneficial to install a large tank next to the pump to allow for a smaller and slower pump to catch up to the amount of water that is discharged from your water softener.

Sink Drain Pump

Such a tank is exactly the reasoning behind the use of a sink drain, by using a large container it is able to quickly collect large amounts of waste water which then allows it to be pumped away slowly by a smaller pump.

If the basement or crawlspace is above the water table a sink drain could also be combined with a dry well. This way the pump won't have to work as much as part of the discharge will be able to taken up by the surrounding soil, allowing you to save on electricity.

These types of pumps cannot handle pumping any debris, therefor make sure to keep the sink basin covered to avoid any debris (or persons) falling into the tank.

Sump Pit

A sump pit and pump are normally used to gather excess groundwater, for example due to rainfall, at a low point and pumping it away when a certain critical level is reached. If present it is possible to drain your water softener discharge into the sump pit.

When doing so, make sure that the volume of the basin and the throughput of the sump pump used to get rid of the backwash is high enough.

Like with a sink drain a sump pump can not handle any debris or particles, it is therefor important when attaching the air gapped drain line that the sump pit stays covered to avoid any debris from falling in.

To extend the lifespan of your sump pump it may be beneficial to periodically clean any salt residue from the pump as salt could increase corrosion thereby damaging the pump.

Can You Drain Your Water Softener Outside?

If local regulations prevent you from draining into the sewer or perhaps if you've installed your water softener outside. You might be wondering if it is possible to drain your water softener outside.

The easiest way to drain your water softener backwash outside is to simply run it onto the ground, however, as there is a lot of salt in the backwash it can be very harmful to the ecosystem and the local water treatment facilities.

Caution: Keep in mind that in some places local rules and regulations might prohibit you from using this option as groundwater might be used as a source for the local drinking water supply.

This high salt content makes it perfect for other applications like killing weeds or deicing your driveway, however, unless you have plants that can survive in high salt concentrations any vegetation surrounding the drain location will likely be damaged or even killed by the discharge.

Luckily there are options to reduce the adverse effects of the minerals contained in the discharge, for example by spreading it over larger area's or by stretching the drainage out over longer time periods.

If your water source is an onsite well make sure the drain location and the well source are at least a 100 feet apart and that the drain location is preferably downhill from the well source.

Failing to do so could potentially contaminate your well with the minerals contained in the water softener discharge.

If the required distance cannot be assured you might be better off looking at other options like offsite discharge.

Best Backwash Drain Options Outside

Caution: Before implementing any of the solutions below, be sure to consult local authorities for any rules and regulations around surface or subsurface discharge of water softener backwash!

When installing a drain outside make sure the drain line ends with a proper air gap and that the end of the hose is covered to protect it from any wildlife or outside contaminants.

In colder climates it is best to keep any drainage away from your homes' foundation, as the high salt concentration could potentially damage the concrete over time.

Dry Well

As the name suggest this is a well but instead of taking water out you put water in. A dry well is nothing more than a deep hole with a porous wall that allows for a slow soak of backwash into the ground and groundwater.

As long as a dry well is implemented above the water table it can accept large amounts of water in a short amount of time which can then slowly make its way into the surrounding ground over a longer time.

This prolonged dissipation makes it a perfect solution for draining water softener backwash as it prevents a sudden increase in sodium concentrations in the surrounding soil.

Alternatively, an old septic tank can serve as a perfect substitute for a dry well. To convert your existing tank clean your tank and disconnect the outlet pipe, clean it out, and make small holes scattered around the bottom of the tank.

Finally, fill up the tank with pea stone attach the water softener drain and your tank is ready for use.

French Drain

A French drain is like a dry well, except instead of using a deep hole that spreads the salt taken up by the soil over time, the backwash is dispersed over a larger area.

A pipe with interspaced holes is placed along a long ditch and is covered by pebbles. The longer the ditch, and the more branches it has, the more dispersed the backwash will be thereby avoiding any high concentrations within an area.

The pebbles assure there is enough space for the water to prevent the ditch from overflowing when your system is discharged, giving the soil time to absorb the backwash over time.

Septic System

Similar to a French drain a septic tank with a drain field are a great way of dispersing the salt over larger area's and many are successfully using this setup.

If you have a septic tank and drain field as onsite wastewater treatment system be sure your tank is big enough for it to handle the amount of brine that is discharge from your water softener. A smaller tank doesn't have the capacity to give solids enough time to settle to the bottom.

Over time these solids will start to slowly clog up your drain field which could eventually stop it from working.

Do Water Softeners Harm Septic Systems

Apart from the blockages of leach fields due to smaller capacity tanks and some reports of natural minerals reacting with the brine causing blockages, despite concerns that have been raised over the years, studies have never conclusively shown any negative effects of brine discharge into a septic system to the digestion taking place within the tank.

However, in some states for example Massachusetts and Connecticut, you are prohibited from draining water softener discharge into your onsite wastewater treatment systems.

Caution: Consult your the provider of your onsite waterwaste treatment system for further information as for some systems warranty can be voided if you drain your water softener discharge into it!

If you choose to drain your water softener into a septic system it is best to increase the times of pumping the settle tank, as the high salt concentrations can cause the discharge to settle at the bottom of the tank thereby decreasing the effective size of the tank for your other wastewater.

If you have a septic system but choose to construct a different drain options, like a French drain or dry well, for your water softener discharge be sure to double-check before you start digging to avoid any damage to your septic tank and drain field.

Why Does My Water Softener Keep Draining?

If your system is producing more backwash than expected something might be wrong with it. First, be sure to check your system for any leaks in the seals, hoses, or connectors.

Alternatively, there might be a leak somewhere inside your home and your water softener might be continuously working without you even knowing it. Check all faucets and other water outlets like the supply to the washing machine for leaks.

If there is a continuous flow through your water softener even at times when no water is being used, you might have leaks somewhere in your piping. This often occurs in colder climates after pipes crack when they are frozen during winter.