Why is My Water Softener Overflowing? (7 Causes & Solutions)

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An overflowing water softener is a sign that something isn’t right, and you should act fast to prevent damage to the system and your home.

Here, we’ve shared the most likely causes of an overflowing water softener, and the best solutions to these problems.

📌 Key Takeaways:

  • An overflowing water softener tank could be caused by a clogged drain hose or brine line, a faulty control valve, salt clogging in the brine tank, a faulty water softener control valve, or problems with the venturi valve or safety float.
  • If your water softener is overflowing, shut off your water supply, unplug the softener, and divert water away from the system, while you troubleshoot the problem.
  • Most water softener overflow problems can be resolved at home, but if you can’t work out the cause, you might need to hire a professional plumber.

🔎 How To Tell if A Water Softener is Overflowing

An overflowing water softener won’t always cause a catastrophic flood – although that is the worst-case scenario.

There are a few other signs to look out for that suggest your water softener tank is overflowing:

Water Flowing Out Of The Overflow Line

Most water softeners have two drain pipes: the normal drain line for when water is flushed during the regeneration process, and an overflow drain line for when the softener is overflowing.

If you notice water draining from the overflow line, it’s likely that you have a softener overflow issue.

Low Water Pressure

If a lot of water is leaving your softener system rather than traveling back into your plumbing, your home’s water pressure will probably suffer.

If you notice reduced water flow in your faucets and fixtures or your appliances aren’t operating properly, an overflowing water softener might be to blame.

Low water pressure from tap

Constant Rushing Water

It’s normal to hear the sound of running water when your softener is performing a backwash cycle. This tells you that the brine is flushing through the mineral tank and being drained from the system.

However, if you can hear rushing water constantly from the softener, it’s a sign that something isn’t right and the softener could be leaking or overflowing.

🤔 What To Do If Your Water Softener Is Overflowing

If your water softener is overflowing or leaking, act fast. You want to stop even more water from escaping, so follow these steps to shut off the system and the water flow to your softener tanks:

  1. Find your main water supply valve and switch it off. This valve is usually located inside your house just after the main water pipe enters your home. Locations to check include underneath your kitchen sink, in your basement or garage, or in an airing cupboard.
  2. Engage the bypass valve. Your water supply should now be shut off, which will prevent further flooding. But if your softener also has a bypass valve, engage the valve to divert the flow of water around the softener tank, providing further protection against leaks and overflow.
  3. Unplug the softener. If the leaking was significant, your water softener system might have sustained water damage, increasing your risk of electrocution. To make sure it’s safe to move on to the next step, unplug the softener from the power outlet.
  4. Drain the overflowing tank. If the water softener tank is overflowing out of the overflow pipe and the top of the tank, use a bucket or a wet vacuum to drain the excess water out of the tank. Otherwise, the excess water should drain out of the overflow pipe if you give it enough time.
  5. Troubleshoot the problem. Once you’ve taken steps to prevent additional water loss, you can move on to the next section of this guide, which should help you to troubleshoot and resolve the cause of the overflow.
  6. Safely turn the softener back on. After you’ve fixed the issue and checked that there is no damage to the electricals, turn the softener back on and schedule a manual backwash cycle.
Engaging the bypass valve of a water softener

📋 7 Causes Of An Overflowing Water Softener (And How To Resolve)

Let’s take a look at the 7 most common causes of an overflowing water softener and how to resolve these issues.

Cause 1: Clogged Drain Line

Your water softener can only function properly if the drain lines are clear and allow a consistent flow of water out of the system.

If your water softener’s drain line is kinked, clogged, or twisted, it’ll restrict water flow. This means the softener won’t be able to dispel water as quickly as it needs to keep up with the regeneration (flushing) process, resulting in a buildup of water that may eventually overflow out of the tank.

There are several causes of a clogged or kinked drain line, including iron or sediment in your water, incorrect operating conditions, or wear and tear from years of use.

How To Resolve

Resolving this issue is easy. After you’ve switched off your softener and diverted water away from the unit, detach and inspect the drain line. If it’s clogged or kinked, try to massage out the blockage or the kink.

You might need to replace the drain line if it’s too worn or damaged to function properly.

Cause 2: Clogged Brine Line

A clogged brine line can have similar effects to a clogged drain line and will also prevent your water softener from functioning properly.

The brine line draws brine solution from the brine tank into the resin tank to replenish the sodium in the resin bed during a regeneration cycle. If the brine line is clogged or twisted, it’ll restrict the flow of brine into the resin tank, but water may continue to enter the brine tank, causing it to overflow.

How To Resolve

Again, switch off your softener system and divert water away from the unit, then remove the brine line and inspect it for kinks and clogs. Straighten the tube and remove any clogs that you notice.

If the brine line is past its best, buy replacement tubing that won’t restrict your water flow.

Checking a water softener brine line for clogs

Cause 3: Faulty Control Valve

Your water softener’s control valve is the system’s brain and controls all of the processes, including the softening and regeneration process.

If the control valve is malfunctioning or faulty, it might disrupt the regeneration cycle or cause improper regeneration processes, which could eventually lead to the water softener tank overflowing.

A malfunctioning water softener valve might be due to poor design or simply because the valve is old and unable to operate as it originally did.

How To Resolve

Check that the control valve settings still seem right. Amend them if not, then check that these new settings are in line with the system’s performance.

Control valves, like all other water softener components, have limited lifespans. You might need to buy a new control valve if you think it’s malfunctioning and causing your water softener system to overflow.

Cause 4: Salt Clogging In The Brine Tank

It’s possible for salt to clog the bottom of the water softener brine tank (known as salt mushing), which can prevent water from flowing out of the tank during regeneration.

As a result, water builds up, eventually causing a brine tank overflow.

Using poor-quality salt in your tank is especially likely to cause a clog because the salt won’t dissolve properly when added to water.

How To Resolve

The best way to resolve this issue is to empty the brine tank and get rid of the salt clog as soon as you notice it.

Going forward, make sure to only use high-quality, high-purity salt in the salt tank, such as evaporated salt, which will reduce the likelihood of clogging and overflow. Avoid rock salt, which is high in impurities and more likely to cause clogs.

Water softener salt in brine tank ready for use

Cause 5: Detached Brine Line

We’ve already mentioned that your softener’s brine line might be clogged or kinked, causing a buildup of water in the system.

But another potential problem is that the brine line has partially or completely detached from the float inside the brine well.

This will restrict the amount of water that can enter the line or prevent water flow entirely.

How To Resolve

Resolving an overflow caused by a detached brine line issue is easy: just re-attach the brine line and program a manual regeneration to check that the softener is now drawing and expelling water as it should be.

Cause 6: Faulty Or Detached Float Assembly

While you’re checking that the brine line is attached to the float, check the whole brine float assembly to make sure it’s still as it should be.

It’s possible for the brine water level float cap to loosen over time and drop into the brine tank. When this happens, the brine float assembly will no longer prevent water from rising past a certain point, so the water may rise to the point of overflowing from the tank.

There are a few other issues that could prevent the brine float from working properly. A sticking brine float will also potentially lead to a brine tank overflow. If high iron or sediment in your water or impurities in your softener salt has led to a dirty brine float, this could cause the float to stick in the up position.

How To Resolve

To resolve an issue with a detached brine float cap, locate the cap in the salt tank and attach it securely back where it belongs.

If the brine float is sticking, remove the lid on the cylinder in your brine tank and lift out the float, then run it under warm water to remove any debris or clogs.

Or, if the brine float is worn and old, replace it with a new one.

If you’re unsure, check your user manual for a diagram to see what the brine float should look like in an operating water softener.

Water softener control float

Cause 7: Obstructed Brine Tank Injector (Venturi Valve)

Too much water in the water softener brine tank could be caused by an obstructed brine tank injector.

The injector valve, or venturi valve, draws brine out of the tank using suction (or venturi). The valve has a small hole that makes this possible, and if the hole becomes clogged, it will be unable to create proper suction.

There are a few reasons why your brine tank injector might become clogged. If your water contains high iron levels, the clogging could be caused by iron deposits. Impurities from the water softener salt could also cause clogging of the injector hole.

Another potential issue with the injector is a torn seal, which will prevent the softener from drawing at the brine draw stage.

How To Resolve

If the brine tank injector is clogged, you can resolve the issue by removing the injector and cleaning the hole in running water to remove the clog.

If you can’t unclog it, consider buying a new one. Brine injectors are cheap and easy to replace.

Also check the pistons and spacer stack for damage. Observe the valve while it’s in service to see if you can see water flowing across it. If you can, you might need to replace the piston or seals/spacers. This is a more challenging job and you might need professional help.

Many of the moveable parts in your water softener are small and delicate, so be careful when you take them apart and make sure they’re all returned to their proper positions before you start using the softener again.

📑 Final Word

Fixing a water softener overflow is easy – but only once you know the cause of the leaking.

Use the steps in this guide to troubleshoot an overflowing water softener and make sure the issue is properly resolved before you switch your water softener system back on. The last thing you want is for your softener to overflow again while you’re away from home.

If you’re still not sure why your water softener is overflowing, keep the bypass valve engaged to divert water away from the softener while you contact a plumber and arrange for a professional inspection. A plumber should have the experience and expertise to uncover an issue that you may have overlooked.

❔ Water Softener Overflow: FAQ

How do I stop my water softener from overflowing?

The fastest way to stop your water softener from overflowing is to engage the softener’s bypass valve, which will divert water away from the unit. With no water to draw into the system, it should quickly stop overflowing. Alternatively, if your softener doesn’t have a built-in bypass, locate your home’s main water valve and turn it to shut off the water supplying your whole home’s plumbing system.

Should there be standing water in my water softener brine tank?

There shouldn’t be standing water in your softener brine tank if you have a new system that has a dry brine tank design. The brine tank should only contain water an hour or two before, and during, the regeneration process, when water is sent into the tank to mix with the salt and form a brine solution. However, a traditional wet brine tank will always contain standing water – but this water shouldn’t overflow out of the tank.

Can water softener cause flooding?

Yes, a water softener can cause flooding if the softener becomes clogged or the control valve malfunctions. However, most modern water softeners have some form of flooding protection, such as an overflow drain, which will send water out of the system if it exceeds a certain level inside the tank.

Is it normal for my water softener to drain water?

Yes, it’s normal for your water softener to drain water, as long as it isn’t constantly draining. Most water softeners have two drain pipes: one to drain the regeneration water and one that serves as an overflow pipe. If you only notice the softener draining water every few days, this is a normal occurrence and happens when the resin bed is flushed out with brine. If your softener is draining constantly, there may be a blockage or malfunction in the system.

Does water softener need overflow?

A water softener doesn’t need an overflow for everyday operation when it’s working properly, but the overflow pipe serves as an emergency solution in case there’s an issue that causes the brine tank to fill too high. If you want to protect your home against flooding, you should make sure a drain overflow is installed on your softener.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

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