Some people use a metal detector to find underground pipes. This tool makes it easy to find leaking pipes or those people need to be careful with during a new construction project. Basically, a metal detector works as a tool to locate survey marks. 

Underground pipes run in a straight or diagonal line. To find them, you need to:

  • Set the metal detector sensitivity to High
  • Determine the underground pipe’s general direction
  • Locate the pipe joints
  • Proceed to locate the entire pipeline.

Knowing how to locate an underground pipe can be helpful, especially when you are experiencing problems with your water supply. That said, it is equally important to know what the signs of damaged underground pipes are.

Can You Use A Metal Detector To Find Underground Pipes? How?

Underground pipes are buried 3 to 6 feet beneath the ground surface. They are usually hidden in walls of concrete, which makes them physically inaccessible. So, if you need to find underground pipes, you need to use a metal detector.

Metal detecting for underground pipes
Metal detecting for underground pipes

Detecting an underground pipe is relatively easy. According to Don Davis of ehow.com, “And cast iron conducts electricity much more efficiently than dirt, rock or concrete, so large, iron tubes are readily apparent to operators of metal detectors.” Meaning the metal detector would be able to catch the signals of the underground pipes even if they are buried eight feet underground. (source)

However, using a metal detector is a difficult thing to do. The reason is that there are other items buried in the ground that the metal detector could also catch. Additionally, the ground itself could be mineralized, making the search process more difficult.

So, how do you use a metal detector to find underground pipes? Here is a step by step guide:

1. Get your metal detector

Understandably, not everyone has a metal detector in their garage. So, if you are one of the people who do not own this tool, do not fret, as you can always rent one. 

Check the internet to find the nearest rental service to you. Once your tool is delivered, read and familiarize yourself with how it works. Make sure that the one you rented will let you evaluate if buried items are metal or non-metal. 

After you are familiar with the metal detector, set the sensitivity setting to high. Make sure that the discrimination setting is set to ignore non-ferrous objects. (source)

2. Determine one end of the underground pipe

If possible, find one end of the underground pipe’s course. You can use that as a starting point to determine the pipe’s general direction. 

Metal Detecting Tip: Searching for a pipe end helps determine a direction. Is the pipe running form a building? Is the pipe running down to the street? These are clues to track where the pipe is located.

Use a metal detector to find underground pipes. Hold the disk-shaped search coil just above the ground surface. Next, sweep it back and forth in slow-motion while you hunt for the underground pipes. 

The signal strength detected will increase once you get near the pipe and peak when you are already above it. 

Moreover, make sure to mark the start and endpoints of the pipe. Also, mark the entire pipeline with a straight line. (source)

3. Locate the pipe joint

Once you have located the pipe’s direction, the next thing you need to do is locate the pipe’s joints. This step is helpful, especially if you need to remove the damaged section of the pipe and replace it. 

To find the pipe’s joints, sweep the metal detector on the area where the pipeline is running. Then, mark the areas where the signal peaked. 

Now that you already know where your underground pipe is, you can proceed to dig it. This way, you will be able to find the damaged parts and repair them. (source)

How To Configure Metal Director Settings For Finding Underground Pipes

There is a chance that you are not yet familiar with metal detectors. Even worse, the user guide that comes with the device is sometimes hard to understand. But if you want to use a metal detector to find underground pipes, you need to know some basic settings. 

Moreover, the most challenging part to understand about metal detectors is probably the settings. The reason is that there are different terms that you need to figure out.

That said, look at the table below for a better understanding of how to configure a metal detector:

Metal Detector SettingHow To Configure
Stock Settings*The stock or turn-on-and-go settings are an excellent place to start. 
*Usually set at 60 to 70 percent power with iron and foil discriminated out
*You can set the stock settings to 7 of 10 as a starting point.
Discrimination*Discrimination settings work from left to right on the conductivity scale with the iron as a low conductor.
*Setting the discrimination level low will let you detect the underground pipes.
*But it will also detect signals from other metals buried near the pipe.
Notch Setting*A notch setting removes a category that the metal detector can catch. Meaning it allows you to bypass certain types of metals and focus only on iron pipes. Such makes it easier to use a metal detector to find underground pipes. 
*The notch setting works using the discrimination option. When you go from left to right, you are eliminating certain metal types one by one. 
Ground Balancing*Many metal detectors use a factory preset, so you do not need to worry about its ground balancing. 
*Almost all metal detectors have a quick grab option. This way, you only need to press a button and pump the coil from 1 to six inches off the ground to set the ground balance. 
Operating Frequency*This setting influences the depth and sensitivity of a target. 
*The lower the frequency is, the deeper signals the metal detector can catch. (source)

Signs That Your Underground Pipes Need Repair

Now that you know how to use a metal detector to find underground pipes, the next thing for you to know is how to determine a damaged pipe. 

Underground pipes experience corrosion due to constant exposure to moisture. As a result, the water that passes through it becomes contaminated with rust. When worse comes, your underground pipe can even have a hole where water leaks.

There will come to a point when your underground pipe acquires damage that calls for repair. When is that? No one knows. However, seven signs point pit potential pipe failure. 

Digging for pipes
Digging for pipes

1. Water discoloration

Turning your faucet on to see that the water flowing out is yellow or brown can be unsettling. If your water supply comes from the city or town supply, then the discoloration may be a sign of a damaged pipe. 

Moreover, the yellow or brown color is a result of corrosion that stains the flowing water. Such is one problem where you can use a metal detector to find underground pipes. 

2. Foul odor

If there is a foul sewage odor coming from your drains, it can signify a crack in the underground pipe. This crack causes the sewer gas to escape. As a result, you can smell it from your kitchen sink or bathroom. 

It is important to note that even the faintest smell can be a sign of underground pipe crack. 

3. Slow draining and backups

Another sign of a damaged underground pipe is a slow flushing toilet. If you observe that your sink, toilet, and shower are backing up with sewage, it is an indication that your pipes are blocked with corrosion. But if the backup only happens to one drain, then the problem may be isolated to that drain. 

In this regard, you need to use a metal detector to find underground pipes. Once you have found the pipeline, the next thing you will do is have a professional dig it and replace the damaged part. 

4. Cracks

Cracks in your walls or foundations can also indicate an undetected leak in the main sewer line. An underground pipe leak can cause the ground to destabilize and develop a void. As a result, your walls and their foundations can develop cracks in the long run. 

A leaking underground pipe can even lead to the settlement of your home. It can even produce a sinkhole if the leak goes unfixed for years. 

So, if your home is not on pilings and you see any foundation and wall-related problems, chances are there is a leaking or broken underground pipe. 

5. Unusually healthy lawn

A sewage leak from a cracked or damaged underground pipe acts as a natural lawn and plant fertilizer. So, if you notice that your lawn became a lot healthier than usual, there is a chance that your underground pipe can be leaking or is in poor condition. 

Use a metal detector to find underground pipes. To do the job easily, check which part of the ground is always wet or which part of the lawn is always healthy. This area can be the part where you can locate the leaking underground pipe. 

6. Lawn indentation

A cracked underground pipe saturates the soil consistently. As a result, the ground dissipates in time, which causes a lawn indentation. So, if you notice that your lawn has a dip above the pipeline, the best thing to do is to use a metal detector to find underground pipes with damage. 

7. Mold problem

If your underground pipe is near a wall and you notice mold growth, it could be a sign of a leaking pipe. The reason is that the leak increases the humidity level, which serves as an invitation for molds to grow. (source)


David-Humphries-Metal-Detecting

David Humphries, Writer and Creator of METAL DETECTING TIPS. After borrowing my son’s detector and finding $.25. I felt like a treasure hunter. FREE MONEY! I was seriously bitten by the metal detecting bug.


Sources

  1. Don Davis, How To Locate The Underground Cast Iron Pipes, https://www.ehow.com/how_10067584_locate-underground-cast-iron-pipes.html, accessed November 13, 2021. 
  2. Sandy Patterson, How Do I Find Underground Copper Pipes?, https://www.quora.com/How-do-I-find-underground-copper-pipes, accessed November 13, 2021.
  3. Finding A Water Main Leak With A Metal Detector, https://terrylove.com/forums/index.php?threads/finding-a-water-main-leak-with-a-metal-detector.43354/, accessed November 13, 2021.
  4. Scott Clark, How Can I Use A Metal Detector To Find A Surveyor’s Pin?, https://www.quora.com/search?q=how%20to%20use%20a%20metal%20detector, accessed November 13, 2021.
  5. Metal Detector, https://en.wikipedia.org/wiki/Metal_detector, accessed November 13, 2021.