Sound of Running Water Behind Washing Machine? (Causes and Fixes)

Hearing the sound of running water behind your washing machine can be concerning, especially if you’re not sure whether it’s normal or a sign of a plumbing issue. While some water sounds are part of the washing machine’s normal operation, others could indicate a leak, faulty valve, or drainage problem.

This guide covers the possible causes of running water sounds behind your washing machine, how to diagnose the issue, and the best steps to fix it.

What Is Normal and What’s Not

Before jumping into troubleshooting, let’s determine if the running water sound you’re hearing is actually a problem.

When the Sound Is Normal

• You hear water rushing for a few minutes when the washer starts a cycle. This is just the inlet valve allowing water into the drum.
• You hear water draining during the rinse and spin cycles. This is part of normal operation.
• The sound stops when the cycle is complete, and there are no leaks or unusual water buildup.

When the Sound Might Indicate a Problem

• You hear constant running water, even when the washer is off.
• There are dripping sounds or slow trickling water behind the machine when it’s not in use.
• You notice water pooling behind or under the machine.
• There’s a hissing noise near the water valves.

If your washing machine is not running and you still hear water, you may have a leak in the supply hoses, a faulty water valve, a drain issue, or a hidden plumbing problem. Let’s go through the possible causes one by one.

Possible Causes of Running Water Sounds Behind a Washing Machine

1. Water Supply Filling the Washer (Normal)

The most common reason for hearing water behind your washing machine is when it is filling. This happens when the water inlet valve opens, allowing water to flow into the drum.

How to Confirm:

• Run a cycle and listen to when the sound occurs.
• Check if the water stops after the drum fills.

What to Do:

• If the sound matches the cycle and stops afterward, this is normal and no action is needed.
• If the sound continues when the washer is off, move on to the next possible cause.

2. Leaking or Loose Water Supply Hoses

Your washing machine is connected to hot and cold water supply hoses. Over time, these hoses can develop small leaks, loose connections, or wear and tear, leading to a slow but steady trickling water sound behind the washer.

Signs of a Leaky Hose:

• The water sound is constant even when the washer is off.
• You see moisture around the hose connections or small puddles forming behind the washer.
• There is corrosion or mineral buildup around the valve or hose fittings.

How to Fix It:

• Inspect the hoses for cracks, leaks, or loose fittings.
• Tighten the connections to ensure a proper seal.
• If the hoses are old or damaged, replace them with stainless steel braided hoses, which are more durable than rubber ones.

3. Faulty or Stuck Water Inlet Valve

The water inlet valve controls the flow of water into your washing machine. If this valve is partially stuck open, it can allow water to continue trickling into the machine even when it’s turned off, creating a faint but persistent running water sound.

Symptoms of a Faulty Water Inlet Valve:

• The sound persists even when the washer is unplugged.
• Water slowly seeps into the drum when the washer is off.
• The washer overfills, or you notice wet clothes when they should be dry.

How to Fix It:

1. Turn off the water supply valves and see if the sound stops. If it does, the inlet valve is the culprit.
2. Unplug the washer and inspect the inlet valve, which is located where the hoses connect to the machine.
3. If the valve is clogged with debris, clean it with vinegar and a small brush.
4. If the valve is damaged or continues leaking, replace it.

4. Drain Pipe Gurgling or Water Backflow

If the running water sound happens during or after the spin cycle, it could be a problem with how your washing machine drains.

Signs of a Drainage Issue:

• A gurgling or bubbling noise in the drain pipe after water empties from the drum.
• Water draining slowly or backing up into the washer.
• A musty smell from the drain, indicating a blockage.

How to Fix It:

• Ensure the washing machine drain hose is inserted correctly. It should extend 6-8 inches into the standpipe to prevent siphoning issues.
• Flush the drain pipe using a solution of hot water, baking soda, and vinegar to break up any minor clogs.
• If the problem persists, snake the drain or call a plumber to remove deeper blockages.

5. Hidden Plumbing Leak Behind the Wall

If the water sound is constant and doesn’t match the washer’s cycle, the issue may be a leaking pipe inside the wall behind the washer.

Signs of a Hidden Leak:

• The sound of running water persists even when the washer is unplugged.
• You notice soft or damp drywall near the laundry area.
• Your water bill is unexpectedly high without increased usage.

How to Fix It:

• Turn off the main water supply and see if the sound stops. If it does, there’s likely a leak.
• Check for wet spots on the wall or water stains near the washer.
• If a hidden leak is suspected, call a plumber immediately, as prolonged leaks can lead to structural damage and mold growth.

6. Water Hammer or Pipe Vibrations

If the running water sound is accompanied by banging or knocking noises, your plumbing system may be experiencing water hammer. This happens when the water flow suddenly stops, causing pressure surges in the pipes.

How to Fix It:

• Install a water hammer arrestor on the washer’s water supply line.
• Ensure your home’s water pressure is between 40-60 psi.
• If the pipes are loose, secure them with pipe brackets to reduce vibrations.

When to Call a Plumber

If you’ve checked the supply hoses, drain, and inlet valve but still hear unexplained running water, it’s best to consult a professional. Call a plumber if:

• The sound continues even when the washer is unplugged and water supply is turned off.
• You see evidence of water damage behind the wall.
• Water backs up frequently despite drain cleaning attempts.

Preventative Maintenance Tips

• Inspect washing machine hoses every 3-5 years and replace them if they show signs of wear.
• Flush the drain pipe periodically with a vinegar and hot water solution.
• Check the water inlet valve regularly to ensure it’s functioning properly.
• Monitor your water bill for unexplained increases, which may indicate a hidden leak.

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