Informational Guide

Shower Leaking Behind The Wall (Why & How To Fix It)

One of the most common sources of household leaks is the shower, mostly as they leak behind the wall. Learn how to fix it here.

by Ian Haynes

It's essential to keep your house maintained. Frequent touchups and odd fix-ups will ensure that the property value appreciates.

One of the most critical areas to consider is the plumbing system, as these are most susceptible to wear and tear. This is why it comes as no surprise that the global plumbing fixtures market was approximately valued at US$ 83 billion.

Also, 10% of US households waste around 90 gallons of water daily due to leakages. One of the most common sources of these leaks is the shower, mostly as they leak behind the wall.

If you have a shower leaking behind the wall, you should fix it immediately to protect your house from structural damage.

However, you should know why your shower is leaking in the first place. By understanding the parts of a shower, you can easily find the faults in your plumbing to avoid future occurrences.

Here are some of the most common causes of a shower leaking behind the wall that we plumbers come across:

  • Extreme temperatures can cause pipes to freeze and burst.
  • External pressure on the plumbing can eventually cause punctures.
  • Weak plumbing is unable to bear the weight of the concrete and eventually crumbles.
  • Old homes have equally old metal pipes that are eroded by hard water.

How To Tell If Your Shower Is Leaking Behind The Wall (6 Signs)

Shower leaks are quite common and easily detectable as well. Here are some telltale signs that there is water damage behind the wall:

1. Mold Or Mildew

Water leaks behind the shower wall can cause mold or mildew, no matter how well you maintain your bathroom.

They thrive in dark and moist areas like walls or crawlspaces — places not usually accessible for everyday cleaning.

If you spot/smell mold or mildew growth anywhere in the bathroom – especially in corners or non-shower walls – it indicates water leakage behind the walls.

Read More - Cleaning Shower Heads Without Vinegar

2. Blistering Paint Or Wallpaper

The paint or wallpaper in your bathroom usually isn't fazed by steam resulting from a hot shower.

If you notice it blistering, water has impeded between the paint or paper and the wall, causing them to separate.

When compromised, paint rises to cause bulges on the wall and then starts to peel off. Similarly, wallpapers become loose as the used adhesive loses its stickiness.

3. Warped Or Stained Walls

If a wall with no external exposure to water starts to warp or stain, that is a sign of a water leak in your bathroom.

When moisture comes in contact with drywall, it becomes soft, starts to bubble, and breaks into pieces.

If the leak behind your walls reaches the ceiling, it also causes sagging and leakage due to water accumulation.

4. Damaged Bathroom Flooring

A bathroom floor is designed to withstand the odd pool of water. Hence, if you see the floor crack or stain up without any reason, hidden leaks might be the reason.

The pipes directly underneath could be leaking, or the water may have trickled down from another compromised area near the floor.

The damage to your floor is dependent on the type of flooring used. For instance, tiles become wobbly, making it easier to remove them and check for any water or moisture present.

5. Old And Accumulated Water Odor

Water accumulation resulting from leaky pipes often leaves behind a stale odor.

If you notice an earthy or musty smell in your bathroom even after cleaning it, you should check for hidden leaks.

6. Water Dripping From The Ceiling

Spots on the ceiling underneath a bathroom are a clear indication of water leakage. Furthermore, these stains can scatter and begin to pop up elsewhere because the water travels a long way.

A wet floor above is not enough to cause damage to the ceiling underneath. So any brown colored stain or even a sagging roof should be a cause of concern.

Also See - How Often Should I Change My Showerhead?

How To Detect And Fix Shower Leaks Behind The Wall: A Plumber’s Advice

After you have discovered the leaks behind the walls, it is time to repair them. Follow the step-by-step guide below to fix shower leaks and prevent further damage:

1. Check The Signs Of Shower Leak

Since internal leaks aren't visible, you have to look for signs. These include checking the basement ceilings for water stains, especially when someone takes a shower in the bathroom above it, and the tiles or drywall covering a valve.

2. Determine Where The Shower Leakage Is

It is generally not possible to tell if the wall behind a shower is leaking. Therefore, you can do either of the following to check:

  • With the help of a screwdriver, remove the shower plate and check valve connections
  • Remove a part of the wall behind the valve to inspect it and the pipes connected to it

There may also be access panels behind the shower wall that can allow you to examine and repair water pipes. In such a case, remove them using a utility knife or box cutter to determine where the leak is coming from.

3. Cut A Small Window To Inspect

To cut a small window, use a stud finder to locate the studs in the wall. In case they aren't available, you can do it yourself using a measuring tape. Studs are generally placed every 16-inches center to center.

It is good practice to hear for studs behind drywall by knocking on it. Once you find it, use a saw to cut a window of approximately 10x8 inches. Inspect the pipes using a mirror and flashlight to get a better view.

4. Find The Exact Spot Of The Leakage

After you have cut the small window, you can examine the drywall ceiling for water stains below the tub drain and run the water to check the leak in action.

If your suspicion is confirmed, you will find the copper pipes oxidized and displaying a greenish-white discoloration due to the leakage.

5. Turn On The Shower

If there is a water leak when the shower is turned on, you can see it flowing down outside the pipes, confirming the leak's source.

Additionally, the leak may also stem from the showerhead's service pipe or the shower valve, so monitor those parts as well.

6. Fix The Leaking Shower Arm And Shower Valve

If the shower arm is the source of the leak behind the wall, unscrew the metal plate using a screwdriver.

The leak could be because of improperly sealed threading. In this case, use a wire brush to clean the joint and then wrap it with plumbing tape. After that, screw the arm into the water pipe joint.

If the arm isn't the issue, then the valve may be. If so, you need to shut off the water and replace the cartridge. Replacing the shower valve behind the wall may help if the leak comes from the valve's body.

Also See - Replacement Shower Valves For Your Bathroom

How To Fix A Bathtub Leaking Through Wall

If you see signs of a bathtub leaking through the wall, follow these tips to perform adequate repairs:

1. Locate The Leak

Start by wiping the tub's exterior wall with a towel and ensure complete dryness. After that, use old newspapers to wrap the entire area and apply masking tape to hold it all in place.

Lastly, fill the tub with water and check for damp spots on the newspaper, which will confirm the leakage.

2. Fix The Tub Faucet

To fix a tub faucet leaking behind the wall, you should first turn off the water supply and then open the tap to empty the connected pipes of any residual water.

Next, prepare for the job by compiling your tools: pipe wrench, screwdrivers, stem washers, and gasket.

  1. 1
    Start by removing the faucet handle. If there is a cap over the handle screws, remove it using the screwdriver, then pull out the screws and the handle
  2. 2
    Use a wrench to remove the packing nuts used to keep the faucet stem in place
  3. 3
    Replace the old gaskets and washers in the faucet with new ones
  4. 4
    Replace the tub faucet and handle and tighten the screws to keep everything in place
  5. 5
    Lastly, turn the water supply on and check for leaks as it maintains the flow

3. Fix The Leaky Drain

Follow these steps to fix a leaking sink drain:

  1. 1
    Start with removing it using a drain removing tool. You can also use a set of pliers for the drain mesh
  2. 2
    Use a screwdriver to work as a lever when kept between the pliers' handles and turn it counterclockwise to break the drain's putty seal
  3. 3
    Scrape off the putty with a putty knife and use hot water to rinse the sink drain
  4. 4
    Take a 0.5 by 5-inch rope, wrap an inch of putty on it and then roll it around the drain threads. Take another one and repeat the process
  5. 5
    Tie the rope around the rim of the sink drain, which touches the tub surface
  6. 6
    Place the drain back in the tub and screw it tightly. Use pliers and screwdrivers to ensure a tight fit
  7. 7
    Clean away the excess putty and run the water to check for leakages

4. Repair The Bathtub Body Leaks And Grout

To repair the bathtub body or grout, use the following tools: waterproof sealant, rag, sandpaper, and a cleaning detergent.

Here are the steps to fix a grout:

  1. 1
    Clean the leak spot and turn off the water
  2. 2
    Let the grout dry to ensure the sealant adheres in place
  3. 3
    Apply the waterproof sealant by following the accompanying instructions
  4. 4
    Let it dry
  5. 5
    Check for leakage by turning the water back on

Here are the steps to fix the bathtub body:

  1. 1
    Clean the tub's interior and mark the spots that need to be fixed using a water-based marker or wax pencil
  2. 2
    Apply a waterproof sealant and let it dry completely
  3. 3
    Use sandpaper gently to remove the excess sealant and smoothen the fixed spot

Damages of A Leaking Shower If Unfixed

As harmless as a shower pipe leaking may seem, it is not. It may not pose any problems initially but can cause damage if left unattended.

  • High Water Bills:
    Dripping water may not seem a lot in quantity, but it can waste tens of gallons daily — resulting in high utility bills.
  • Health Risks:
    Mold can grow in moist areas and lead to respiratory problems, eye infections, skin rashes, fever, etc.
  • Expensive Tile Repairs:
    Leaky showers can cause excessive damage-over-time and result in the need for a complete renovation overhaul – including expensive tiles. 
  • Unappealing Water Stains:
    Continuously dripping water can cause brown- or copper-colored stains on the ceilings and walls, giving them a very unsightly look.


Is there a tool to detect water leaks?

You can use various water sensors to detect hidden water leaks. These can cost you between tens to hundreds of dollars.

Does homeowners' insurance cover plumbing leaks in walls?

If the leaks in your wall are sudden or accidental, the insurance will cover them, but you will have to fix them if they result from over-time neglect or wear and tear.

How much does it cost to fix a leak in the wall? What about just for leak detection?

Leak fixes cost around $150 to $350, and their detection costs a separate $100. These costs do not account for post wall repairs. You can find free quotes from your area by filling in the form below.


Shower leaking in the wall is generally undetectable, and you have to rely on signs to find and fix it.

If you do not repair your shower leak in the wall, you will eventually face more significant structural and health-based damages that could have been avoided!

Related Article - Learn How To Easily Plumb a Bathroom

Ian Haynes is an expert writer who has successfully deployed over 500 plumbing pages and other related content. He has an excellent understanding of home plumbing issues and translates his experiences via Plumbing Lab so readers can have a better understanding of common household problems. Outside of his work, Ian likes exploring Brooklyn with his Labrador.