How To Find A Water Leak Inside A Wall

Any water leak inside a wall significantly reduces the quality of your home environment. Such hidden leaks in your plumbing system affect the quality of the air you breathe while causing extensive damage to your walls.

Leaks are also one of the major causes of water wastage in your household. And, it might be the main reason why you keep on paying a high water utility bill month after month.

How can a water leak inside a wall affect your monthly water bill?

Well, do you know that, on average, small slow leaks release approximately 7-15 gallons of water every hour? This is equivalent to 2-4 cups every minute.

On average, leaks can waste approximately 7-14 CCF’s every month. CCFs is the amount of water you have used as indicated on your bill.

See, you always end up paying for water leaks out of your own pocket- directly or indirectly. Water wastage from leaks alone can account for half of your water bill each month.

Additionally, they lower the quality of your home atmosphere, putting your health and that of your loved ones at risk. And, we all know how expensive proper medical care has become in this era.

Often, leaks in your plumbing fixtures and pipes go undetected because they happen silently. You might go for months without noticing that there is a water leak inside your walls. Or any other part of your home.

Unless, of course, you spot some of the obvious signs of water damage -which signify extensive destruction. And, even then, you might find it difficult to locate the source of the leak since most of these signs appear far from the actual source of the damage.

To keep your home healthy, you should always test for water leaks in your plumbing system regularly instead of waiting for the unpleasant signs of water damage to appear.

How often? Every time you suspect there might be a water leak in (around) your household. There are two major clues that ought to raise your suspicion from time to time.

Signs Of Water Leak Behind Wall

Here are some clues that indicate the presence of a hidden water leak inside a wall.

A Musty Smell in the Air

You’ll often start to feel the surrounding air becoming unusually stuffy before you smell the dampness. For this to happen, though, you must have the ability to be in the present moment and trust your sense of smell.

A Dramatic Increase in Your Water Bill

A sudden spike in your monthly water bill may mean that you have a hidden water leak, as explained in this article.

Generally, finding a water leak inside a wall is not difficult. It is something you can do within a few hours, as you are about to learn below. We will not only look at a step-by-step process on how you can find a water leak inside your walls. But also, what to do once you find it.

I will summarize the entire process into 3 main stages. Each stage has its own set of actions.

Stage A – Finding out whether there is a leak in your home or not.

In this stage, you are simply testing for the presence of a leak. You need to ascertain a leak in your home before you start looking for it. I mean, you wouldn’t want to spend your time looking for something whose presence you are not sure of, would you?

Stage B – Looking for the place where the leak is taking place.

At this point, you already know that there is a leak in or around your home. However, what you don’t know is the place where the leak is taking place. Your home is divided into many areas.

At this stage, you are simply trying to narrow it down to the specific area where the leak is. Is it in your kitchen? Bathroom/ showers? Behind your walls? This is an important aspect of the entire exercise because you’ll determine whether the leak is inside your walls. Or not.

Stage C – Finding the actual source of the leak.

Once you’ve known the place where the leak is happening, it’s now time to try and locate its actual source. You must do this because it’s the only way to stop the leak. And begin to restore your home.

For example, if you find that the leak is inside your walls in stage 2, stage 3 will help you know the exact source of the leak behind your walls.

Now, let’s look at the steps you need to follow at each stage mentioned above.

How To Find A Water Leak In 6 Easy Steps

There are a few tools you will need to test for the presence of a leak in your home. These tools include Your eyes, Pen, Paper, and Water Meter.

All materials mentioned above can easily be found in and around your home. Add a screwdriver to the mix. Depending on the location and type of water meter you have, you might need it to access your water meter.

Step #1

Shut off all the water-dependent appliances in your home, including the water heater, washing machine, dishwasher, and sprinklers. Ensure all the faucets are properly closed as well.

Step #2

Find your water meter. Usually, it is located somewhere outside your house- at a place, the official meter readers can access, on foot, easily.

Specifically, look for some form of cover in one of these two most likely places around your household. That is:

  • Your driveway – mostly check someplace close to the curb.
  • Your front-yard.

Here, you look for plastic, metallic, or even concrete covering that protects your water meter.

Step #3

Once you’ve successfully located your water meter, carefully open its cover to check and record the number of water usage. That is the total number of water gallons that your home has consumed. Note this number down as your first reading.

Your screwdriver might come in handy at this point if your water meter is one of those that are difficult to access with your bare hands. Depending on how the cover is fitted on the meter, you might need to use the screwdriver to open it. So you can get the meter’s reading.

If the covering is loosely fitted, slowly pull it open using your hand, then get your reading. But, if it’s fixed a bit more tightly, simply use your screwdriver.

How? By gently passing it through the cover hole and pulling it open.

Avoid using excessive force when using a screwdriver to access your water meter. The whole exercise is rather simple and does not demand unnecessary force from your end.

Step #4

After recording your first reading, leave the water completely turned off for a minimum of 3-4 hours.

During this testing period, don’t let ANY water run (both inside and outside your house). Do not even attempt to flush your toilet within this period. Doing this increases the level of accuracy of your final results.

Step #5

Check your water meter again once the 3-4 hour waiting period is over. Read and record the water usage number as noted in step 3 above. This will be your second reading.

Step #6

Finally, compare the results of your second reading to your first reading. Can you notice any difference?

How can you tell if you have a water leak?

Essentially, you are looking to see if both readings are the same. Or if your second reading is higher than the first. If you find they are the same, you can ensure there is no leak. Hence, get rid of any worries you might have on whether you might leak or not.

But, if you see that your second reading is higher than the first, it means there is an increase in your water usage. Which, in turn, is a clear indication of the presence of a leak inside or around your home.

You can be sure there is a leak because, remember, you did not actively use any water inside your house during the entire testing period, right?

And, you also completely shut off all the water-dependent appliances plus faucets the whole time. So, any increase in water usage at this time can only come from water leaks.

How Can You Tell Where A Water Leak Is Coming From?

After confirming that you have a leak in your home, your next course is finding out where the leak is happening.

To do this, you must first employ the elimination method. So you can get rid of the obvious places you are likely to experience leaks in and around your household.

The most obvious places to check include:

  • Your toilet’s tank parts, including the flapper valve.
  • Under your bathroom and kitchen sinks
  • Areas around your showers and bathtubs- are there any drips of water?
  • Areas close to your water heater and the hoses of your washing machine- do you see any small pools of water?
  • Irrigation systems and water faucets found outside your house.

How do you tell if there is a leak behind a wall?

Once you find out there is no leak in all the likely places mentioned above, you can be sure that you have a hidden leak somewhere in your plumbing system. The main challenge you are faced with at this point is knowing whether the leak is inside your walls or not.

Of course, some obvious signs indicate the presence of a leak behind a wall. Some of them include peeling, bubbling paint, cracking, discoloration, and small pools of water at the base of the wall.

But, as we’ve already seen, such signs mean that extensive damage has already taken place. Yet, we are trying to locate any water leak so earnestly in this exercise to find it in good time. Thus, preventing any damage from getting to its extensive level.

So, Is there is a way you can tell if there is a leak behind a wall before any of the obvious signs mentioned above appear?

Specifically, there are two things you must do to find out early enough- if the leak is behind your walls:

  1. Look for a persistent earthy smell in the surrounding air.
    This is easy to notice as you can always tell when the quality of the air you breathe changes from room to room.
  2. Listen for the sound of a leak behind your walls.
    The best time to do this would be late at night. You’ll be able to quickly hear the sounds of small drops of water inside your walls in the dead silence of the night. If you hear the sound of small drops of water or a subtle hiss of running water, mark that spot. Marking such spots properly will make your work easier when it comes to locating the actual source of the leak, which is what you’ll be doing in the final stage.

Locating The Actual Source Of A Water Leak Inside A Wall

At this final stage, you are trying to pinpoint the exact location of the hidden leak behind your walls.

There are several ways to do this. All involve the use of leak detection equipment of some kind. We will discuss only 2 ways in this post.

In my opinion, using either a moisture meter or an infrared camera are the 2 easiest ways of locating the source of a leak behind a wall.

Scanning A Water Leak Inside A Wall Using A Moisture Meter

How does a moisture meter work? A moisture meter is a special piece of equipment that analyzes a wall’s moisture content. They (moisture meters) are easy to use.

All you have to do is place the moisture meter against a wall- directly, and it scans to reveal the wall’s moisture content. This way, you can easily tell if there is a leak at a particular point inside your wall.

Specifically, you’ll be looking to confirm if the moisture content exceeds the acceptable levels for the wall. Or not.

What moisture level is acceptable in drywall?

Readings on a moisture meter are usually in percentages- ranging from about 5% to 40%. When using a moisture meter to locate the source of a leak, keep the following points in mind:

  • A reading of 5 to 12% is considered an optimal range
  • Readings of 12 all the way up to 17% are considered moderate. Thus, acceptable moisture levels.
  • Any reading over 17% is a clear indication of high moisture levels. 

Signify the presence of a leak behind that particular point of your wall or nearby.

Are moisture meters accurate for drywall?

There are moisture meters that are specifically designed to be used on drywall. Commonly referred to as moisture meters for drywall, they accurately detect even the smallest increase in moisture content inside walls. Including a slight increase of about 0.1% above what is considered normal moisture content for drywalls.

However, when purchasing a moisture meter to use on drywall, always check to confirm that it has extended-length pins. Longer pins will help you find the source of a water leak behind your walls more accurately.

Important Tip: If you could not pinpoint a potential leak’s exact location under stage B, put your moisture meter at various spots on the wall. Approximately 6 or 7 different spots. The spot with the highest moisture content reading is directly linked to the source of the leak. Or closest to it.

What is the best moisture meter?

I have found 4 highly recommended moisture meters that will give you the best value for your money. Any one of these 4 moisture meters will help you find the source of a water leak inside your walls successfully.

  1. General Tools 4-in-1 Digital Moisture Meter
  2. Proster Digital Wood Moisture Meter Handheld
  3. Wagner Meters Orion 940 Pinless Wood Moisture Meter
  4. Extech MO55 Pin/Pinless Moisture Meter

Finding A Water Leak Inside A Wall Using An Infrared Camera

Overall, infrared cameras are used to detect heat. Thus, indicate a wall’s temperature. As a result, it is easy to tell whether there is a leak at a certain point in your wall or not. Wet areas will always be cooler than the surrounding regions.

Using an infrared camera is simple: You place it close to the object or wall being scanned for a leak. Then, look at the coloring on the screen. Hot objects have a red or orange color, whereas cool objects appear blue or purple.

What is the best Infrared Camera to use?

There are 3 high-quality and easy-to-use infrared cameras you can spend your money on:

  1. Hti-Xintai Higher Resolution Infrared Thermal Camera
  2. FLIR TG267 Thermal Camera
  3. FLIR C5 Thermal Imaging Handheld Camera with WiFi
  4. Hti-Xintai 220 x 160 IR Infrared Thermal Imager
  5. Seek Thermal Revealpro Imaging Camera

Important Tip: Most emergency water damage restoration professionals use infrared cameras to find the source of water leaks in homes. Therefore, you can always choose to rent one from them instead of buying one- if you know, you won’t need to use it too frequently.

What to do once you find out that you have a water leak inside your walls?

The best possible solution is to contact a well-licensed water restoration expert as soon as possible. So you can prevent any further water damage to your walls. Trying to address the leak all by yourself might be a tedious task.

In general, it would involve removing the entire sheetrock or wet drywall carefully, either completely drying out or replacing all the materials that have been affected by water damage. You must also fix the actual source of the leakage, alongside any other plumbing repairs that may crop up.

Sound like a lot to handle on your own, right? Well, it is.

Especially if we add the fact that you may not have all the proper tools needed for the tasks, but there is no job too big or too complicated for the right water damage restoration company.

In fact, with certified professionals, your only job would be to call and explain the situation to them. Everything else will be well taken care of from that point on. And, you can comfortably:

  • Trust that your home is in good hands.
  • Count on advanced cleaning, repair, and remediation techniques that are effective and efficient
  • Navigate all the insurance paperwork with professional help from the restoration company.


That’s it! Once you follow all the steps as laid out above, you can be sure that your home is in good hands. And will be fully restored in the shortest time possible.

Remember to document each and every step you take once you confirm the presence of a water leak inside your home. As noted in our previous discussion, documentation is crucial if it turns out that you need to file a claim. You must provide sufficient proof that you did not neglect the leak to let it worsen. Instead, you took the necessary steps to contain the situation before filing any claims.

We’ve looked at the manual process of finding water leaks in your home from time to time. Clearly, you must first test for the presence of a leak, then look for the place of its occurrence before finding its actual source.

Also, you should know- there is an easier way to test for the presence of a water leak inside your home. Time is the most valuable yet priceless resource we’ve all got. And, if you can save it in one way to use it wisely in another- the better your life will turn out.

Of course, testing for the presence of a water leak as described in stage A above is worth your time. You get to maintain a high-quality home atmosphere while protecting your bank account in the long run.

However, as I mentioned earlier, there is an easier way that involves the use of water leak detectors. You can always rely on a good water leak detector to inform you whenever there are leaks in your home.

In fact, water leak detectors are a must-have home aid equipment. They will detect any leak on its onset. Then, send you an alert so you can take the necessary action as explained in stages B and C. This way, you cut the total time taken to find any hidden leak inside your wall by half.

Mas Broto

Written by: Mas Broto

Mas Broto is a small business owner with 30 years experience in the real estate industry. He is the founder and editor of, the most comprehensive free home improvement website on the planet!

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