Why Washing Machine Overflows When Filling?

The start of every washing machine cycle begins with water filling up the washer tub. Even older models know precisely when to stop filling up with water. So why do some washing machines overflow when filling up?

There are a few common reasons why washing machines overflow when filling. There may be a problem with the water pressure switch or with the water inlet valve being stuck in OPEN position.

Thankfully, this is a problem that’s straightforward to fix. In this article, we’re going to look at those common causes and what you can do to resolve them!

Let’s get started.

Why Washing Machine Overflows When Filling

Water Pressure Switch

What is it: All washing machines have something called a water pressure switch. Its only function is to figure out how much water is inside the washer drum at any given time. 

When it detects no water in the drum, it’ll power the water inlet valve to let more water flow in. When there’s enough water in the drum, it’ll cut the power to the inlet valve and stop the flow.

The water pressure switch looks almost like any other kind of component you’d find inside an electrical appliance. The one significant difference is that it uses an air tube to measure the machine’s water levels.

When water fills the drum to where it should be, the tube’s air will compress and activate the water control switch.

Why it fails: If the washing machine is overfilling itself with water, the problem may be with the water pressure switch.

The switch can’t detect that the tub is full and allows the inlet valve to stay open.

Excessive amounts of water will flow into the tub and overflow out the sides.

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There are two possible reasons why the water pressure switch is failing to do its job.

The first could be that the air hose is somehow compromised. There could be something inside that’s blocking the air from flowing, or it may have small holes letting air out.

The other possibility is that there may be debris or some kind of sediment in the switch itself.

Remember: it has an air hose that leads into the switch so that dust may have found its way into the switch itself.

How to fix: If a water pressure switch is causing your washing machine to overflow, then resolving the matter is pretty straightforward.

You can resolve the issue by cleaning the hose and making sure that the pressure switch works properly.

The first thing you’ll need to do is remove the switch and the hose. Be sure to unplug the power supply to the washer before using a screwdriver to remove any unit panels.

It’s always a good idea to refer to your user manual, though a water pressure switch is effortless to identify thanks to the air hose.

You can remove the air hose and clean out anything that’s blocking it. At the same time, you could also check the entire line for any noticeable leaks.

Once you’ve cleaned and inspected the hose, test your water pressure switch to make sure it works.

Reattach the air hose and blow into it. If the switch works, you should hear a clicking sound in the switch.

If there’s a problem there, you may have to replace the switch.

Water Inlet Valve

What is it: Washing machines also have what’s known as the water inlet valve.

That is the ‘gatekeeper’ that controls the flow of water into the tub. You’ll often see that these have connections for two hoses instead of just one.

That’s because you can use it to connect to your home’s hot and cold water supplies.

The water inlet valve works closely with the water pressure switch discussed earlier.

When the switch detects that the tub is empty, it’ll cause the water inlet valve to open.

That will continue until the tub is full and at the right temperatures that you’ve chosen. If you’ve chosen a higher temperature to watch your fabrics, it’ll let in more hot water as a result.

Once there’s enough water in the tub, the water inlet valve will shut, and the washing cycle can begin.

That entire cycle will repeat when it comes time for the rinse cycle.

The machine will drain all the water out, and the valves will open once more to bring in clean water for the machine to use.

Why it fails: Assuming all other parts are working, a faulty water inlet valve could be the reason for your washing machine’s overflow problem.

You’ll notice that water continues to flow into the tub even though it’s already full!

Most likely solenoid valve jammed in OPEN position, allowing water to keep filling the drum.

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Water inlet valve

Diagnosing this is pretty easy. Unplug your washing machine from its power supply, but keep the water supply open. Suppose that water keeps flowing into your machine even when it’s unplugged. 

That means that the water inlet valve is faulty and that you need to have it replaced.

How to fix: The first thing you need to do is refer to your user manual if you have it. It’ll tell you where on your machine to locate the water inlet valve. More importantly, it should also list the item number for that part, which will make it much easier for you to purchase a replacement.

To replace the valve, you’ll need to disconnect both the power supply and the unit’s water supply. Remove the panelling of your washer and figure out where the valve is.

That shouldn’t be too hard to do. You can locate it by seeing where your water supply connects to on the body of the washer.

Before removing any connections, you’ll want to place a towel inside somewhere underneath the valve. That’s because there may be some leftover water inside the valve that you’re removing. You don’t want that water to spill out when you pull the valve!

Once you’ve removed the old valve, it’s time to put the new one in. Secure it with the same mounting screws that you opened earlier. Then, reattach the wire connectors and the water supply hoses.

Switch on the water supply to make sure that there aren’t any leaks or water dripping out. That’s how you’ll know that you’ve fixed everything properly!

Low Incoming Water Pressure At the Water Inlet Valve (Not Likely)

What is it: There is one more possibility related to the water inlet valve. For the water inlet valve to stay closed, it requires a minimum amount of water pressure.

With around 20 psi of pressure from your home water supply, those valves will remain closed even when the power supply to the washing machine is off.

Why it fails: In this situation, the problem arises when there’s a lack of water pressure from your home water supply.

Suppose that’s the case, then the water inlet valve cannot shut correctly, and water will continue to flow into the tub unrestricted.

Slowly but surely, your washing machine will overflow, and water will spill out all over the floor.

How to fix: Fixing this requires you to check your household water pressure.

Since it’s a problem that’s beyond the washing machine, you may need to refer to a plumber to troubleshoot why your house does not have enough water pressure in its water supply.

Is There Any Washing Machine Overflow Protection?

Yes, some washing machines models do come with some form of overflow protection.

Sometimes, they might refer to it as part of its ‘flood protection’ features instead. In any case, the function is the same: to prevent the washing machine from overflowing and flooding your entire laundry area.

Here’s how it works.

When the washing machine detects that there’s too much water in the tub, or it senses that there’s water spilling out to places where it shouldn’t go, the overflow or flood protection will kick in.

Typically, that means shutting off the water inlet valve automatically and powering the drain pump to let all the water flow out.

Some machines might do this for a set amount of time, while others may only run until it has emptied all the water in the washing machine.

Suppose all of these features work correctly. That will prevent an overflow that could potentially damage your laundry room and everything inside.

Why Is My Washing Machine Overflowing With Bubbles?

There are situations where a washing machine might overflow with bubbles instead of water.

Sure, this might sound funny and look like something out of a comedy. But you don’t want this to happen, as you’ll have to spend a lot of time cleaning all of them out of your laundry room!

There are two reasons why your washing machine might overflow with suds, and both of them have to do with your detergent.

The first possibility is that you’ve used an excessive amount of detergent to wash your clothes.

As your clothes spin and all that water splashes around, the mixture will create way more bubbles than your machine can handle.

You’ll start to see suds flowing out of your machine and onto your floor, especially when you open the door at the end of the cycle!

If you have a habit of using too much detergent, you may also have a problem with detergent residue stuck inside your washer.

With each wash, that residue builds up until it causes your wash cycle to create too many suds, leading to an overflow of bubbles as well.

While it might be frustrating to clean out all those bubbles, preventing any further overflow is very easy.

Firstly, cut back on how much detergent you use with each cycle. The best way to do this is to refer to the detergent bottle and follow the instructions closely.

You’ll want to cut back whenever you’re washing a half load or less, as well.

Secondly, you’ll need to clean all the detergent residue left inside your washer tub.

Many washing machines nowadays have a self-cleaning cycle that you can select. Run that every once in a while and that’ll solve the problem for you.

If you do not have an automatic self-cleaning option, you can just do it yourself.

Run a rinse cycle without any clothes in the tub, and choose the hottest water temperature possible. That will dilute and flush out any detergent residue you may have in your washer.

Final Thoughts

An overflowing washing machine can be a nightmare, mostly if it flows out and floods your entire laundry room. Besides choosing a high-quality washing machine, you can also prevent this by selecting a model with sufficient overflow or overfill protection.

Reader Comments (1)

  1. At night I have left my washing machine unplugged from power source and in the morning I have water on my floor from overflow, my husband removed the switch and cleaned the hose, and blew into it but we don’t here any clicking noise, is it the switch or the water inlet valve? The machine has worked well for a while, so he doesn’t think that it is less than 20 psi, but buying parts we don’t need is a problem, we live 132 miles from the nearest repair man. All information is greatly appreciated, thank you so much!

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