Adverse effects of softener discharges on septic tanks (2023)

Adverse effects of softener discharges on septic tanks (1)

Here are the answers to that question and the effects of using a fabric softener with a septic system.

It is not true that regeneration emissions from water softeners are a problem for septic systems or for the leach field. Studies have shown that regenerative waste from water softeners does not interfere with the bottom flow of the septic tank system, but because of the polyvalent water hardness, cations in the regenerative discharges improve soil permeation, especially in fine textured soils.

WQA has research reports from the University of Wisconsin and the National Sanitation Foundation on septic tanks and softeners. This research was completed in the late 1970s. It was at this time that several regulatory agencies considered restrictions on the discharge of softener waste to private sewage treatment plants.

Recently, the US Environmental Protection Agency underwent this investigation report, and an expert in on-site waste treatment wrote in October 1993 that he "does not believe the conclusions of the previous study would change since soil chemistry and physics have not."He also goes on to say that he knows that this work remains scientifically excellent“.

These studies show conclusively that the effluent from the softener does not cause problems for septic tanks.

(Video) How will a water softener regen discharge affect my septic system? | Ask Tom

The discharge permit for water treatment installations for hundreds of thousands of septic tank installations is now almost universal. It has not caused any damage or danger, but it has brought convenience and financial savings to many homeowners. This conclusion is supported by the ten states'Recommended standards for individual wastewater systemsThe states have concluded that even in montmorillonite clay soils, the removal of brine waste from water softening equipment has no significant effect on the permeability of soils suitable for soil absorption systems.

Adding sodium to a septic system with soft water actually has beneficial effects on the digestion of waste products by bacteria. the amount of waste from a softener added to the septic tank is not enough to cause harmful hydraulic loading problems. In fact, they are smaller in volume and rate of addition than waste from automatic washing machines. Calcium and magnesium in the softener regeneration waste contribute to proper air and water movement (enhanced soil leaching) through the drainage field of the septic system.

Reports from the University of Wisconsin and the National Sanitation Foundation clearly indicate that when the sodium content of the softener's regeneration cycle is discharged into the soil through a septic system along with other salts such as calcium, magnesium and iron, the result is an improvement in the soil percolation instead of an injury.

A letter from Dr. Fred P Miller, Professor of Soil Science, Department of Agronomy, University of Maryland, draws the same conclusion. Dr. Miller points out that when the septic system receives only water containing very low mineral content and does not receive the mineral salts from the backwash cycle, this condition "can lead to swelling and spreading of clay and reduced hydraulic conductivity in the absorption field".

There are other benefits directly related to the use of softened ion exchange water, when the hardness minerals calcium and magnesium are removed by softening. The homeowner uses less soap - studies have shown as much as 50 - 75% less. Also, less biodegradable products are discharged into the system, which relieves the load on the system.

It is a known fact that many homeowners do not properly maintain a septic system. Failure to pump the system at proper intervals can allow detergent solids, as well as other solids, to enter the drain area, causing blockages. By having soft or spotless water available, the homeowner's fabrics are also cleaner and the amount of water used can be reduced. This significantly reduces the load on the septic system.

(Video) Will A Water Softener Harm My Septic System?

Many people may be under the impression that water treatment equipment regenerates quite frequently and introduces a high load of sodium salts into the wastewater. This is of course not true, the average family of four would need softener regeneration about four to five times a week.

The water quality improvement industry has been seriously trying to find out the actual information about fabric softener waste water. The septic tank study clearly indicates that there are no adverse effects when the effluent with water treatment is discharged into properly installed private septic systems. There are a few additional reports that also explain further evidence that the hardness ions in softener regeneration waste cause less clogging and maintain a higher permeability than regular septic tank effluent.


Shakespeare certainly didn't have the problem of deciding whether to use a fabric softener with his septic drainage system. But with 20 million household disposal systems, this question has been asked by many homeowners. Can softened water cause problems for consumers on a septic system? After focused research, the answer is NO - softened with confidence.

The on-site domestic waste water system is simple to operate. The main ground line of a home's plumbing system terminates in a concrete or steel tank buried a prescribed distance from the home and below the frost line. The usual single-chamber container has a screen near the feed line, which prevents the build-up of wastewater and reduces turbulence in the incoming waste. Once the wastewater enters the tank, the heavier solids sink to the bottom, while more liquids rise to the surface. Various bacteria present in the wastewater, as well as other organisms introduced into the tank, digest the waste material and chemically alter it. the bacterial action that works in the absence of oxygen is called an anaerobic process. Another ventilated system is operationally similar, but the breakdown is aerobic, i.e. needs air.

After the bacterial action has taken place, relatively clear water is discharged through the outlet pipe of the tank. It flows to a distribution box, from where it is routed through perforated, loosely connected pipes to the drainage field. The loose joints and perforations allow seepage into the surrounding soil. To increase water drainage, pipes are generally laid in beds of gravel or loose rock.

(Video) 4.3 - Eric Yeggy - Softeners and Septic Systems: Get the Facts

This concerns the case side of the disposal system. The other side concerns water before it reaches the tap and has the water softening system.

A typical water softener uses a resinous material that attracts sodium ions. The ion exchange resin reacts with the incoming water and replaces the sodium ions with the calcium and magnesium ions. Calcium and magnesium are naturally occurring minerals found in many water sources. The presence of these ions makes the water "hard", replacing calcium and magnesium ions with sodium or potassium ions "softens" the water. During the regeneration cycle, the hardness ions are removed from the softener exchange resin and discharged with the backwash and excess regeneration salt (sodium chloride or potassium chloride) required to initiate the regeneration reaction.

Misconceptions: In the 1970s, a number of provinces and states became concerned about the effects of softened water on septic systems. While the assumptions turned out to be wrong, there were three main reasons for what turned out to be unfounded concerns and false assumptions. It is well known that bacterial life forms are endangered if their environment contains too much or too little salt. It was feared that the higher salt concentration in the sewage or softened water would be harmful or lethal to the bacterial functioning of the tank.

The other concern was that the backwash flow rate during regeneration would add water faster than the tank can handle. This would force wastewater out of the tank before the bacterial action could be complete. In other words, "raw sewage" would be sent to the drainage field.

Finally, it was feared that the brine produced by the softener would reduce the drainage field's ability to absorb water. This assumption came from agricultural studies of high-sodium irrigation systems.

These were "common sense" arguments about a suspected problem and not verified facts resulting from scientific testing. As a result of these assumptions, legislation was passed in some areas that prevented the use of softened water in a septic system. To resolve this situation,the waterQuality Association (WQA)sponsored researchUniversity of Wisconsin (Madison)And withNational Sanitary Foundation (NSF).These groups conducted extensive studies to confirm or refute these assumptions.

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Results promote soothing

The opposite of the above assumptions turned out to be true as a result of scientific testing.

First "the effect of softened water on bacteria was more beneficial than harmful".The normal salinity in "unsoaked, hard" sewage water is far from ideal for bacterial growth. The addition of sodium to the system was found to move the bacterial environment closer to the optimal range. Soft water was "healthy" for the organisms.

Second, the amount of backwash during regeneration did not affect the time it took for the bacterial treatment of wastewater, it was easily within the limits the tank could handle.

It was noted that on these grounds an automatic dishwasher would pose a greater threat than a fabric softener!

Concerns about the absorption rate of salt and soil were also dispelled. The elevated sodium content of the tank runoff was found to have no adverse effect on the soil's ability to absorb water in a normal drainage field. Interestingly, certain soil conditions have benefited.In addition, when the softener's calcium-rich regeneration backwash is discharged into the septic system, the runoff can actually improve soil percolation.(Gypsum, a mineral high in calcium, has long been used to increase the porosity of clay soils.)

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The conclusions of these tests are that softened water is NOT harmful to a normally functioning septic system or drain field.This is of course good news for anyone who suffers from dirty dishes or clothes or suffers from precipitation in the pipes due to hard water.

Homeowners can enjoy all the benefits of soft water without worrying about it interfering with the efficiency of the household's septic system.


Adverse effects of softener discharges on septic tanks? ›

Studies have shown that water softener regeneration wastes do not interfere with the septic tank system drain field soil percolation, but because of the polyvalent water hardness cations in the regeneration discharges improve soil percolation, particularly in fine-textured soils.

Will water softener discharge harm septic system? ›

Water softeners, while tempting for residents with “hard” water, produce a salt-heavy discharge (brine) that can have adverse effects on the septic treatment process, local vegetation, and the water supply if improperly disposed of.

How does a salt water softener affect a septic system? ›

Septic tanks are designed to allow solids to sink to the bottom so that clear effluent can flow out to the drainfield. The high concentration of salt brine from the water softener interferes with this process, which can ultimately allow solids to flow out to the drainfield and cause failure by clogging the pipes.

Is water softener discharge bad for the environment? ›

Chloride in water threatens our fresh-water fish and other aquatic life. The chloride used in home water softeners can also affect the water used for drinking. It takes only one teaspoon of sodium chloride salt to permanently pollute five gallons of water. Once salt is in water, there is no easy way to remove it.

Will downy fabric softener hurt septic systems? ›

Is this fabric softener septic safe? Yes. P&G evaluates environmental safety of all ingredients used in our products. All Downy products are expected to be safe as long as they are used as intended and the septic system is functioning properly.

Where do I drain my water softener discharge? ›

Where To Discharge Your Water Softener System Backwash
  1. Discharge It Directly Into a Drain Pipe Near the Floor. ...
  2. Dump It Outside. ...
  3. Use a French Drain. ...
  4. Dump It Into a Dry Well. ...
  5. Use a Septic Field. ...
  6. Consider Using Subsurface Discharge If You Are Permitted. ...
  7. Weed Killing and Removal. ...
  8. Get Rid of Slugs.

Is water softener discharge corrosive? ›

Softeners do not remove the TDS and do not cause this type of corrosion. A softener is simply capturing some cations (mostly calcium and magnesium) and releasing other cations in the process (usually sodium or sometimes potassium). The use of dissimilar metals in the plumbing can lead to galvanic corrosion.

What happens when water softener salt runs out? ›

If your water softener runs out of salt, then the softening resin will become saturated to the point that no ion exchange can take place. Thus, the calcium and magnesium minerals will remain in your water. Sometimes, the water softener tank may even overflow.

Can water softener drain into sewer line? ›

In most communities, it is illegal to connect the water softener drain directly to the home drain system without an air gap. Similar to the requirement for dishwashers, the drain line needs an air gap fitting designed to prevent back-siphoning of contaminated drain water into the water softener.

How much discharge does a water softener produce? ›

Used properly, softeners regenerate one to three times per week and produce between 40 and 150 gallons of brine per week. If the water softener is set up incorrectly the amount of brine can be much higher.

What is the downside of a water softener? ›

The major disadvantage to softening water is the potential health risks for people that might be on low sodium diets. The exchange of hardness minerals for sodium adds 7.5 milligrams per quart for each gpg of hardness removed. In addition, calcium and magnesium are eliminated from the homeowner's diet.

What are the side effects of softened water? ›

The sodium in softened water stops plants from growing and can even kill them. Soft water can also cause severe problems for people with diabetes or high blood pressure. It also exceeds the recommended sodium intake of babies and pets by a significant amount. It can also lead to serious complications.

Why are water softeners banned in some states? ›

The most common reason why water softeners are banned in some states is that they don't meet environmental discharge standards set by the state or local authorities within the state. What is this? The discharge from a softener system has a high concentration of sodium ions and hard water minerals.

Is it true you shouldn't use fabric softener? ›

Yes! Fabric softener creates a waxy coating that can actually ruin your clothes over time. This is because fabric softener essentially applies a thin, waxy coating to your laundry which must be water-resistant to survive the washing process.

Is laundry detergent bad for septic systems? ›

If you have a septic system, it's best to avoid using laundry detergent pods. This is because they contain high levels of chemicals and surfactants that can build up in the septic tank over time, potentially causing issues. Also, their small size increases the likelihood of causing clogs in pipes or filters.

Why is fabric softener not recommended? ›

Your fabric softener may contain phthalates, which disperse scent; synthetic musks such as galaxolide, which accumulate in the body; and much more. Fragrance mixes can cause allergies, skin irritations such as dermatitis, difficulty breathing and potential reproductive harm.

Will the water softener water damage the grass? ›

Soft water has only one nutrient - salt. Watering your lawn with soft water may wash away minerals and nutrients from the top soil which can make it harder to maintain healthy grass.

Why is my water softener discharging? ›

This is normal. What happens during the regeneration process? During the regeneration process, the water softener floods the resin with brine water, thereby “cleaning” the hardness minerals off the resin and sending them down the drain.

Why does my water softener keep discharging water? ›

If your water softener is trickling or flowing water constantly into the drain, this is very wasteful. The water could be coming from the back washable filter or a dedicated iron filter if you have one installed in your system.

Why is soft water a problem for plumbers? ›

Since soft water contains very few dissolved minerals, it tends to leach minerals off other surfaces, including your metal plumbing pipes. This can result in pitting and pinhole leaks in metal plumbing pipes.

Can water softeners cause bacteria? ›

There will be bacteria in your water softener, but it is not harmful bacteria. Bacteria are found everywhere – particularly in substances where there are minerals, such as water. They are completely harmless and, in a lot of cases, help us to function as living things.

Can a bad water softener make you sick? ›

For most healthy adults, the amount of sodium added to tap water by softening is too small to be harmful or cause any health concern.

Is it bad to put too much salt in water softener? ›

Don't Add Too Much Salt

Adding too much salt to your water quality softener can cause salt “bridging,” or a buildup and solidification of regenerant. This buildup can prevent your system from regenerating properly.

How often should you change salt in water softener? ›

In general, we recommend adding a bag of salt every month. At the first of each month check your brine tank and you'll be able to monitor your salt usage and adjust as needed.

How long can you go without salt in water softener? ›

The Length of Time Needed Between Salt Regenerations

The general advice would suggest adding salt every 8 to 12 weeks, but some people have found that their usage does affect these times – so instead check once weekly at least. You will eventually know how much salt your water softener uses, and when it regenerates.

Do water softeners clog pipes? ›

Because these water softeners use resin beads to condition the water, and these beads sometimes escape into the plumbing works, Do not be too alarmed. Those yellow resin beads are not toxic, but they do clog up the smaller passages in fixtures and appliances.

How often should a water softener drain? ›

Typically, the regeneration should occur after every 12 to 14 days or it should occur after a predetermined gallons of water that you use. You can set the number of gallons used before it regenerates through the water softener's valve.

Does a water softener drain need an air gap? ›

An acceptable air gap must be twice the diameter of the discharge piping and above the flood rim of an individual vented receptor (example). In addition, all residential water softeners must have an air gap that is at least one and a half inches.

Is sodium chloride safe for septic systems? ›

A lack of or excessive amounts of salt will kill the beneficial bacteria in the septic tank. Therefore, excess salt concentrations in septic tank effluent can have a detrimental effect on the sewage treatment capabilities of the septic system.

What is the maximum distance a drain should be from a water softener? ›

The drain should not be more than 30 feet away from the softener and the drain line should not be elevated more than 8 feet above the floor.

How long does a water softener discharge? ›

The hard minerals and brine are discharged into the drain. The time this takes can vary from 30 minutes to maybe 100 minutes.

Is there an alternative to a water softener? ›

The most common alternative to water softeners is called a water conditioner and offers a viable way to reduce the damage hard water can cause throughout your home through a process distinct from the process used by water softeners.

Can soft water cause stomach problems? ›

Softened water may cause diarrhea

The most common side effect of drinking softened water is gastrointestinal discomfort. This condition usually occurs because people aren't used to drinking softened water.

What should my water softener hardness be set at? ›

A basic rule of thumb is that the hardness level of water should not exceed 120 to 170 mg/L, which equates to around 7-10 grains per gallon of water. Whether you get a lab test or do it yourself at home, the hardness level can be determined by an accurate water analysis report.

Who should not drink softened water? ›

There are two specific situations where the use and drinking of softened water is inadvisable. These are: In the reconstitution of infant formula powders, as softened water could affect its fine nutritional balance, or; For anyone on a medically prescribed low sodium diet.

Can dogs drink softened water? ›

The softening process slightly raises the sodium content of the water, but it's still suitable for drinking. Softened water is safe for most pets – and people – to drink.

Can you water plants with soft water? ›

But watering plants exclusively with soft water isn't recommended. Most water softeners use sodium chloride, which can cause a gradual build up of sodium in garden soil. This can cause plant growth problems. Instead of soft water, use hard water or reverse osmosis for watering plants.

Is it safe to drink water if you have a water softener? ›

You can drink softened water, but it's important to check the hardness level beforehand. If it's below 400 ppm, then it's safe to drink. If it's above 400 ppm, then you will need to place a reverse osmosis filter to get rid of the sodium levels.

Why did Texas ban water softeners? ›

The main focus behind the state bans is to protect damage to septic systems and municipal wastewater facilities. High concentrations of sodium discharged into septic tanks harm the beneficial microbes, which affects its ability to break down solids.

Why are water softeners illegal in California? ›

The cost of treating this wastewater is significantly higher than other types of waste, and much of the water treated in this way still isn't recoverable. Thus, in 2005, California took action and made it legal for communities to ban this type of water softener in order to meet toughening environmental standards.

How can I make my towels smell good without fabric softener? ›

Add half a cup of white vinegar to your rinse cycle

'Add half a cup of white vinegar, instead of fabric softener, to your rinse cycle to break up any residue that may be in the towels. Don't worry: as your towels dry the vinegar smell will disappear, leaving your towels smelling fresh and clean and feel soft.

Is there a natural fabric softener? ›

The Kitchen Concoction: Baking Soda & Vinegar

With a few items found in your kitchen pantry, you can mix up your own natural fabric softener. All you need is water, baking soda and vinegar, plus a few drops of essential oils if you'd like it scented. Stir until mixed and add in one-part vinegar (ex: one-half cup).

Which is better dryer sheets or fabric softener? ›

Fabric softener's better but still has problems

Fabric softener doesn't have all the problems that dryer sheets have. As long as you use the right amount, clothes should come out soft and static-free. Also, most brands don't affect absorbency or wicking, according to Consumer Reports.

Is Dawn dish soap bad for septic systems? ›

Most laundry and dishwashing detergents have phosphates and surfactants which can easily soak into the drain field. Apart from harming the beneficial bacteria, these phosphates and surfactants can also seep out of the septic tank in their toxic state thereby contaminating the groundwater.

How many loads of laundry a day are safe to do with a septic tank? ›

Spread Out Laundry Loads

These use less water which puts less stress on your septic system. Regardless of the type of appliance you have, you should still spread out your loads. Instead of doing several loads in one day, consider doing 1 load per day or space out 2 loads if you must do more in a single day.

Why does my septic system back up after washing machine? ›

Using too much laundry powder will cause the undissolved powder to clump together inside your septic system. If these clumps of powder get caught in the system's inflow lines, they can cause serious blockages, which may lead to sewage and wastewater backing up into your home.

Why should you not use fabric softener on jeans? ›

Never use fabric softener or dryer sheets

To give jeans that soft feel, fabric softeners coat the surface of the denim with a thin layer of chemicals, which, albeit mildly, abrade the fibers. Over time this stress adds up and unnecessarily wears out the fabric.

What happens if you use too much fabric softener? ›

Using too much fabric softener

Towels especially are impacted, because that coating inhibits their ability to absorb moisture. Excess fabric softener also builds up in your wash machine over time, and may eventually begin leaving stains on clothing which can ruin them.

What can mess up a septic system? ›

What are some common reasons a septic system doesn't work properly?
  • Pipe from the house to the tank is clogged. ...
  • Inlet baffle to tank is blocked. ...
  • Outlet baffle or effluent filter is clogged. ...
  • Drainfield has failed.

How much water does a water softener discharge when it regenerates? ›

Used properly, softeners regenerate one to three times per week and produce between 40 and 150 gallons of brine per week. If the water softener is set up incorrectly the amount of brine can be much higher.

Can you drain water softener into sump pit? ›

Manufacturers of sump pumps discourage the use of sump pits to discharge brine from the water softener. Sump pumps and associated components such as float switches are not designed for exposure to salt water.

What's the worst thing for a septic tank? ›

Diapers, cigarette butts, cat litter, and sanitary napkins don't belong in your septic tank. You can keep your septic tank “clean” by only filling it with human waste.

What is the most common cause of septic tank failure? ›

Most septic systems malfunction because of inappropriate design or poor maintenance. Some soil-based systems (those with a drain field) are installed at sites with inadequate or inappropriate soils, excessive slopes, or high ground water tables.

Is Dawn dish soap safe for septic systems? ›

A: Yes it is. I have used Dawn ever since it first came out and have never had one septic issue and I use Dawn for cleaning and spot cleaning a lot of stuff. Also, it's safe to use in animals and birds who wind up getting covered in petroleum so you should feel comfortable using it as well.

What happens if you shower while water softener is regenerating? ›

If you're showering with hot water while a single tank water softener is regenerating, you will be using the hot water from your hot water boiler tank, and then your hot water boiler tank will be re-filled with untreated, hard water.

How many gallons does it take to backwash a water softener? ›

Some softeners may use between 20 to 25 gallons of water during regeneration, some may use anywhere from 35 - 65 as numerous factors play into the final gallons used.

Can I put Clorox in my septic tank? ›

Although bleach effectively destroys germs, it can also ruin your septic system. Bleach kills both good and bad bacteria. If the good bacteria are destroyed, your tank won't be able to break down waste effectively. As a result, your septic system will become clogged with waste.

What is the safest dish soap for septic systems? ›

Safest Dishwashing Detergents
  • Aldi Foaming Dish Soap.
  • Amway Home Dish Drops Automatic Dishwashing Powder.
  • Dropps Dishwasher Pods.
  • ECOS Dishmate Dish Soap.
  • Method Dish and Dishwasher Soaps.
  • Seventh Generation Dish Liquid.
  • Seventh Generation Automatic Dishwashing Gel: Free & Clear.
Jul 18, 2022

What cleaners should not be used with septic systems? ›

Avoid using cleaners that contain toxic bleach, ammonia, phosphates, or petroleum-based chemicals, which can harm your septic. Instead, use proven natural cleaners.

What is the best way to drain water softener? ›

Scoop out the water from your water softener with a cup or bucket. Get a clean bucket or cup: Find a bucket that's small enough to fit inside your brine tank or use a large scoop or bowl. Scoop out the water: Scoop out the water manually and dump it into a larger container to dispose of down the drain.

How often does water softener drain? ›

Typically, the regeneration should occur after every 12 to 14 days or it should occur after a predetermined gallons of water that you use. You can set the number of gallons used before it regenerates through the water softener's valve.


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5. How to dispose of saltwater with a septic tank
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