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How To Detect Underground Water Leak

By July 4, 2023Inspections
How to tell if you have a water leak underground

Coming home from work, you check the mailbox and your water bill has arrived. You know what the average monthly bill so you aren’t anticipating anything different. When you open it up, you see that the bill has doubled! Perplexed, you are thinking maybe your teenager is taking longer showers or the sprinkler system is running longer. The next thought is, maybe it is a water leak. Wondering how to detect underground water leak? Check the water meter, drop in water pressure, high water bill, or hire detection services company.

Tree roots can grow into a pipe and cause water issues.

Why Do Water Leaks Happen?

There are various reasons why underground water leaks happen. They can be due to some of the following:

Chemicals – sometimes chemicals are in the soil or water and can cause pipes to fall apart and erode. Thus, causing water to get through.

Earthquakes – these can cause pressure on the pipes and make them move. Thus, causing splits or cracks.

Older Homes – pipes will wear out and become rusty as the home ages, also causing leaks and cracks.

Pipes Not Installed Correctly – always make sure a professional is the one who installs pipework and that it is done correctly. If it is not, pipes can leak.

Roots From Trees – invasive roots from trees can grow close to pipes or crack them and cause leaks as well.

Low water pressure is an indicator of a water leak underground.

Signs There May Be An Underground Water Leak

High Water Bill

Unless you have kids home from college or your lifestyle has changed, the water bill should stay about the same each month. Look at water bills from the past few months. If you notice an increase, it is a good time to call a home inspector to check out the plumbing.

Decrease In Water Pressure

If you notice low water pressure and your municipality hasn’t notified you about it, this is a good way to detect an underground water leak. This could be because the pipes are clogged, eroded, or ruptured. 

Sometimes this happens in neighborhoods where there is new construction. Therefore, notifying the superintendent in charge or the builder may be helpful so they can check the drains outside.

Cracked Pavement or Bulges in the Driveway

These signs indicate there is a pipe that has cracked and a water leak underground.

Cracked Foundation or Wet Spots

Foundation cracks can cause structural issues so you want those checked out. Also, wet spots in the yard indicate something is going on and needs more investigating.

Air or Dirt in Water

This is not normal in your water. If you are finding this, there may be an issue somewhere in the pipes.

Unpleasant Smell

If dirty water isn’t going where it is supposed to, the sewer, and it is starting to smell, there could be a blockage or cracked pipe. This is a great time to call a home inspector to check it out.

Water in Street

This is often in front of homes that a pipe has burst. As a result, the water has nowhere to go so it heads to the street.

Homes Over 30 Years Old

Older homes will have issues with plumbing as their life expectancy is only so long. Thus, the plumbing may be on a downward spiral as some pipes may become corroded or break due to weather or the age of the home. Inspecting the plumbing system early is important so you can tell if you have a water leak underground.

What Are the Steps To Detect and Find An Underground Water Leak?

Now that you know you have a leak somewhere, let’s look at how to find a water leak.

  1. Locate the Water Meter . Check for water usage while the main water valve is shut off. This will allow you to know if there is a water leak underground.
  2. In the water meter is a leak indicator. This is usually a small triangle that is red, white, or blue in color and it spins when water is being used in the home. Since the water valve is shut off, this triangle should be still. However, if it is spinning, then there is a leak somewhere underground.
  3. Maybe you don’t have a leak indicator? That is okay! The other way is to look at the water meter reading and write it down. Then, leave the main water valve off for half hour to an hour. After that time, record the water meter reading and see if there are changes. If there are, you have a leak.
  4. Check the yard – If you see plush green, signs of water and wet soil in weird places, water pooling, or sinkholes, you may have an underground leak and need a professional to check it out.

How Do I Detect a Water Leak?

If you suspect there is a water leak underground on your property, contact a qualified plumber or engineer as soon as possible to identify and fix the issue. They will use a variety of specialized water leak detection devices to narrow down the location of the leak which will reduce the additional costs and disruption that comes with digging to try and find the problem. Some techniques they may use include:

Thermal Imaging

This is using a specialized camera to find the locations of pipes and where they are buried in a structure. Thermal imaging is a service you can order from your home inspection company and it can show the temperature differences in a surface and any leaks that there may be.

Leak Noise Correlation

This involves using electronic devices that are powerful and can locate leaks on pipes that are pressurized and the leaks location is unknown. How this works is two sensors are in contact with the pipe and then sounds are recorded. Then, the sounds are sent to a radio processing unit. Lastly, mathematical algorithms are used to find the leak.

Trace Gas Leak Detection

Trace gas does not cause harm to pipework and is non-toxic. It is used for finding leaks in pipework and heating systems that are under the floor. How it works is it pressurizes the gas through pipes and then it is forced up to the surface and escapes. Then, it can be found with a gas detector. Many professionals like this method as it will narrow down where the leak is and even in concrete.

Acoustic Leak Detection

This type of detection is done by using microphones that are ultra-sensitive to listen for leakage from pipework.

Recommended Maintenance

Now that you know about water leaks underground, let’s take a look at a few other areas of maintenance. One of those is how deep sewer lines are buried. It will vary by each state, but in colder climates, they may range from 4 to 8 feet in depth for residential. The city sewer lines are about 12 feet in depth.

Another area is who is responsible for the water meter. As we know this is used to see if there is a water leak but also by the city to read the water meter to see how much water you use. It is the responsibility of the water municipality to take care of the water meter.

Lastly, it is important to know that a clogged toilet can cause a pipe to burst. However, it is good to know that it will depend on the type of plumbing and also the type of clog. It is a good idea to keep in mind what you can and can’t put in the toilet and educate the family on it as well.

When to Call a Professional

It can be serious when you have a high water bill or find other things in the yard that are hinting towards a water leak so hiring a professional is a good idea. A professional can get to the root of the problem and also figure out if it is a leak underground or another issue. This isn’t something to take into your own hands and can get very expensive quickly if not taken care of.


A water leak underground is not a good thing but if caught early, it can save you a lot of money. Keeping an eye on the areas mentioned above and looking and listening for signs will be helpful. Also, calling on a professional for leak detection services may be key. Call on Boggs Inspection Services to get a thermal imaging inspection completed in Lacey, WA, and surrounding areas.

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