Where To Discharge Water Softener Backwash

Backwash is the process of reversing the flow of water through a water-softening system to flush out the trapped contaminants. This water is slightly salty and must be discharged in a way that meets local regulations. The most common and accepted method for disposing of backwash is to discharge it to a sanitary sewer, either by connecting it directly to the sewer pipe or by routing it to a nearby drain.  Knowing the appropriate site and method of disposal is essential for ensuring that water softener backwash will not cause any harm to the environment.

According to a study by the Virginia Department of Health, over 20% of the total nitrogen and phosphorus pollution in the United States is caused by improper disposal of water softener backwash. These contaminants can lead to algal blooms and other aquatic life issues. Furthermore, the buildup of excess salts, such as sodium and potassium, can lead to the salinization of soil and water, which can be especially damaging to agricultural areas.

In this blog post, we’ll discuss the different methods for properly disposing of water softener backwashes, such as using a septic system, a municipal wastewater drain, a dry well, and more. We’ll also discuss the importance of safe disposal and the potential environmental and health impacts of poor disposal.

What Is Backwash Water Softener?

A backwash water softener is a type of water softening technology that uses a reverse flow of water to help remove hardness minerals and other contaminants from the water. This process helps to reduce scaling and improve the water’s quality for various applications. The backwashing process typically involves a tank, which contains a mineral bed, and a pump. The water is passed through the tank and the minerals are removed using a special media. The clean water is then pumped back into the system.

Research shows that backwash water from water softeners can contain elevated levels of sodium and total dissolved solids (TDS). Tests conducted by the EPA have found that the average backwash water contains sodium levels of up to 70,000 mg/L and TDS levels of up to 2,600 mg/L. It is important to note that these levels can vary depending on the type of softener and the amount of water used. In addition, backwash water can also contain additional contaminants, such as phosphates, nitrates, and chlorides, which should be addressed as part of a comprehensive water treatment program. 

Backwash water softeners are an effective way to soften hard water because they reduce the amount of scale buildup in pipes and fixtures. This helps to reduce energy costs associated with running water-using appliances, as well as preventing clogged drains and showerheads. In addition, backwash water softeners help to reduce soap scum buildup and eliminate the need for additional water-softening chemicals, such as potassium and sodium chloride. 

How Often Should Water Softener Backwash?

Generally speaking, a water softener should be backwashed every 2-3 days, depending on the size of the tank, the hardness of the water, the amount of usage, and other factors. This backwash process helps to flush out any dirt, sediment, and other contaminants that have built up in the resin bed, restoring the softener’s ability to soften water.

According to research conducted by the Water Quality Association, it is recommended that a water softener is given a full system reverse flow (backwash) every 2 to 3 weeks to ensure the best performance. Additionally, they suggest that the backwash cycle should be extended to once a week if the water hardness is very high, if the salt dosage is inadequate, and if the system is used heavily.

Where To Discharge Water Softener Backwash?

1. Using a septic system: 

The discharge of water softener backwash to a septic system should be done in a slow and steady manner. This will prevent septic system overload and minimize the possibility of an overflow or backup. Additionally, a backwash valve should be installed to help regulate the flow of water. 

The valve should be adjusted to reduce the flow of water to a trickle, allowing the softener backwash to be discharged over a longer period of time. It is also important to check the septic tank periodically for signs that it is not becoming overfull and to adjust the backwash valve as necessary.

2. Drain into a dry well:

When discharging water softener backwash to a dry well, it is imperative that the discharge pipe is securely connected to the drywell, with a double check valve in place to prevent any backflow. The discharge pipe should be placed as low as possible in the drywell, allowing the water to naturally flow out, and ensuring that the dry well is never filled above the top of the pipe. 

Additionally, the drywall should be checked regularly, and the backwash water should be drained away regularly to avoid it becoming a breeding ground for pests or other health hazards.

3. Drainage field: 

When discharging the water from the water softener backwash to the drain field, be careful that the water is being released slowly and evenly throughout the area. This can be accomplished by using a pressure regulator and a backflow preventer on the discharge line.

The pressure regulator will help to prevent any sudden surges of water that could damage the drain field. In contrast, the backflow preventer will help to guarantee that the water is only flowing in one direction and not back into the water softener. Additionally, it is crucial that the water is not released at a rate that is too fast, as this can cause saturation of the soil in the drain field and ultimately lead to system failure.

4. A municipal wastewater treatment plant: 

Discharging the water softener backwash to a municipal wastewater treatment plant should only be done after consulting with the local environmental protection agency or local officials. Discharging the wastewater should be done at a slow, steady rate with a hose of adequate size to provide a gradual, uniform discharge. 

The water should also be tested for pH levels, hardness, and other contaminants before being discharged. The discharge should be conducted in compliance with all applicable local, state, and federal laws.

What Is A Water Softener Drain Line And How To Install It? 

Water softener drain lines are pipes that connect the water softener system to the building’s main drain line. These lines are important in order to allow the brine solution produced by the water softener to be flushed away safely. The installation of a water softener drain line requires careful attention to local building codes and plumbing regulations.

Find the Drain Pipe 

The first step in installing a water softener drain line is to locate the drain pipe, which will be connected to the water softener. This should be located near the main water line, typically near the water heater, and is usually made of PVC or copper. 

Create a T-Fitting 

Once you have identified the drain pipe, you will need to create a T-fitting. This will be used to connect the water softener to the existing drain pipe. To create the T-fitting, you will need a PVC or copper elbow, a PVC or copper T-fitting, and two PVC or copper connectors. 

Connect the T-Fitting 

Once the T-fitting has been created, it will need to be connected to the existing drain pipe. To do this, you will need to use the connectors and attach them to the T-fitting, then connect the T-fitting to the existing drain pipe. Once the T-fitting is connected, the water softener can be attached. 

Connect the Water Softener 

Following the installation, the next step is to attach the water softener to the T-fitting. To do this, you will need to use the two PVC or copper connectors and attach them to the water softener. 

Install the Drain Line 

Once the water softener is securely attached to the T-fitting, you can then install the drain line. To do this, you will need to measure the distance between the water softener and the drain pipe, then cut a piece of pipe to the appropriate length. Once the pipe is cut, you will need to connect it to the water softener and the drain pipe, using PVC or copper connectors. 

Test the Water Softener 

Finally, once all the connections have been made, you will need to test the water softener to make sure it is working properly. To do this, you will need to turn on the water softener, then check for any leaks or other issues. If the water softener is working properly, you can then begin using it.

How To Drain Your Water Softener? 

1. Gather supplies:

The first step in gathering supplies to drain a water softener is to acquire a bucket that is large enough to hold the softener’s brine tank contents. Additionally, you will need to acquire a hose, tubing, and a wrench. 

The hose should be long enough to reach from the brine tank to the bucket, and the tubing should be long enough to connect the hose from the brine tank outlet to the bucket. The wrench will be used to disconnect the tubes and hoses from the brine tank.

2. Disconnect the softener:

This can be done by unplugging the power cord from the outlet or by turning off the breaker in the breaker box. It is important to note that some softeners may have a bypass switch, and this should be switched off as well. Additionally, the water supply to the softener should be shut off by turning off the valves connected to the inlet and outlet of the softener.

3. Drain the softener:

The third step in draining your water softener is to turn off the water supply to the unit. This typically involves closing the main water supply valve or isolating the water softener from the water supply line. 

After the water supply has been shut off, the bypass valve must be opened to allow the water to escape from the tank. The bypass valve is usually located at the bottom of the water softener. Once the water has been drained out, the bypass valve should be closed again to prevent any further water loss.

4. Clean the resin:

Once all the water has been drained from the water softener, you can start cleaning the resin. This is done by adding a solution of water and a cleaning solution to the resin tank. You can use a broom handle to stir the solution and help dissolve any salt or mineral deposits that have accumulated in the resin. 

Once the resin is entirely free of any deposits, you can drain the cleaning solution and rinse the tank with clean water. Then, you can refill the tank with fresh resin and new salt and your water softener is ready to use.


How much water does a water softener discharge?

The amount of water that a water softener discharges can vary depending on the type of system and its usage. Generally, a water softener discharges between 20 and 55 gallons of water per regeneration cycle.

Is backwash the same as regeneration?

No, backwash is not the same as regeneration. The backwash is the process of reversing the flow of water through a filter so that suspended particles can be removed, while regeneration is the process of restoring a filter media to its original condition by using a chemical cleaning solution.

How often should water softener be backwash?

It is recommended that water softener backwash occur at least once every two weeks while generally, it should be twice a week. However, the frequency may need to be adjusted depending on the number of people using the water softener, the hardness of the incoming water, and the size of the resin tank.


The most suitable option for discharging water softener backwash is to route it to a drainage system, preferably a sanitary sewer. This is the most cost-effective and eco-friendly option, as it will help prevent the backwash from entering natural water sources and will not create any additional expenses. Additionally, it is highly recommended that the water softener is properly sized and maintained to avoid any potential problems associated with excessive backwash.

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