A Friendly Guide to Detecting Hidden Underground Water Leaks

Your good friend Sherleak Holmes, the world famous water leak detection specialist, is here to teach you how to detect underground water leaks.

Looking out at your lawn and seeing a pool of water or soggy soil when you haven’t watered is a red flag that you may have an underground water leak.

A leak from underground pipes can waste thousands of gallons of water, damage your yard and foundation, and lead to flooding or mold growth if left unaddressed. Here are some tips on how to determine if you have an underground water leak and steps you can take to locate and repair it.

Watch for Surface Signs

Yard water leak geyser

The most obvious indicators of an underground water leak are visible signs on the surface. Some things to look for:

  • Wet spots or soggy soil in your yard, especially after it hasn’t rained recently. This may indicate a leak from irrigation pipes or home plumbing pipes. Pay attention to any wet areas that reappear in the same spot after drying out.
  • Grass that is significantly greener or grows faster in one area. If an underground pipe is leaking, the extra water can cause grass or vegetation to flourish in that area.
  • The presence of water puddling on the ground or flowing out from one spot. This may be a major leak and requires immediate attention.
  • Caving or sinking of soil. If the dirt is collapsing, it could mean water is eroding the soil underground.
  • A dip or depression forming in your yard. This points to an underground water cavity forming.

Use Your Senses - Even Your Sixth Sense

I see underground water leaks

In addition to visual signs, you may be able to hear, feel, or smell indications of an underground leak:

  • Listen for the sound of running water when outdoor faucets and water sources are turned off. You may be able to isolate the location of the leak based on the volume.
  • Notice any damp, musty odors coming from your yard. This could signify water buildup underground.
  • Feel the ground. Certain areas may feel exceptionally soft or spongy compared to others if excess water is accumulating below.

Monitor Your Water Bill

Your water bill is higher than normal

A spike in your water bill can also signal an underground leak. Compare recent bills to ones from last year to see if usage has increased substantially without explanation. Perform a thorough check for leaks inside your home first. If no problems turn up indoors, underground plumbing issues may be to blame.

Conduct a Dye Test

Yard water leak dye test meme

To pinpoint the exact location of a suspected underground leak, you can perform a dye test:

  1. Purchase special dye tablets or liquid dye designed for leak detection. Fluorescent dye works best for easy visibility.
  2. Remove aerators/screens from indoor and outdoor faucets. Place dye in multiple sinks and bathtubs. Flush toilets to discharge dye. Activate the irrigation system to disperse dye if needed.
  3. Let the dye run through the pipes for several hours. Check ground surfaces, drainage areas and anywhere you identified signs earlier for the appearance of dye. Fluorescent dye can be spotted with a UV light.
  4. When you locate dye on the ground, examine the area closely. The source of the leak will be near the dye sighting. Mark the spot.

Call a Water Leak Detection Service

If you confirm a leak through the above methods but can’t determine the exact location, contact a leak detection service like USA Leaks. They have specialized tools to detect underground leaks accurately so repairs can be made:

  • Acoustic listening devices pick up the sounds of underground water flow. These sensors can isolate the origin of the leak noise.
  • Ground microphones also pick up the vibrating sounds of pressurized water escaping pipes using digital correlation technology.
  • Pipe and cable locators use underground scanning to create a map of pipes. Leak points become obvious.
  • Video pipe inspection systems involve sending a remote camera probe into pipes to view leaks directly on a monitor.

Once the leak is identified, repairs can be made. This may involve replacing a section of damaged piping or sealing cracks or pinhole leaks with epoxy resin. For major leaks, full pipe replacement may be necessary. Either way, fixing underground leaks as soon as possible prevents further water waste, property damage, and mold risks.

Prevent Leaks with Regular Maintenance

You can help minimize leaks by having your plumbing system inspected annually and replacing aging or corroded pipes.

Installing leak detection devices that sound an alarm at the first sign of a leak is also wise prevention.

And be sure to have irrigation systems professionally winterized each year. Stopping leaks before they happen is the best way to keep your home and yard protected.


If you suspect you have an underground water leak on your property, don’t ignore it. Catching it early makes repairs less extensive and prevents lasting damage.

Follow the above tips to check for signs, pinpoint the source, and take action. With some diligence, you can stay ahead of costly and messy leaks.