Underground leaks can waste thousands of gallons of water before you even notice a problem. Pipe leaks can cause soggy patches in your yard, cause structural damage, or run up your water bill fast. The trick is knowing the telltale signs to look for and what to do about it. You don’t need fancy tools or plumbing experience—just a little awareness and some basic steps to narrow it down.
Start With the Obvious Signs
If you think there’s an underground leak, start with a visual inspection. Walk your yard, look around, and see if anything seems off. Some of the most common signs include:
- Soft, mushy spots in the grass even when it hasn’t rained
- Unusual wet spots or puddles that don’t go away
- Grass that’s greener or growing faster in lush patches
- A sudden drop in water pressure inside your house
- Unexpected increase in water bill or water usage that’s higher than normal without explanation
These clues often show up before extensive water damage occurs. You can also shut off all water inside your home and check your water meter. If it’s still moving, there’s water flow somewhere it shouldn’t be. That’s usually a clear sign there’s a hidden water leak underground.
Test the Meter and Isolate the Problem
Your water meter can tell you a lot if you know how to read it. Here’s a quick test:
- Shut off all water lines inside your home—sinks, toilets, washer, everything.
- Locate the water meter and shut off for the water supply. Usually found in a meter box near the curb or property line in warm climates and indoors in a basement or utility area in colder climates.
- Watch the small triangle-shaped dial (sometimes called the leak indicator). If it’s spinning, water is still moving through the system.
If that dial is turning even though everything’s shut off, the leak is likely between the meter and your house. If it’s not moving, your pipes inside the house might be the issue instead. This helps you know whether to look inside or outside.
Use Your Ears, Eyes, and a Bit of Patience
Once you know the potential leak is outside, you can try narrowing down the exact location. Walk slowly over the suspected area and listen. Sometimes you can hear it running underground, especially if the leak is strong or near the surface.
There are specialized listening devices, but using a long screwdriver can help. Press the metal tip into the ground and place the handle near your ear like a stethoscope. It might sound odd, but it works. Listen for the sound of water escaping, a faint hissing or bubbling sound. Leaks tend to show up in underground water pipes at joints, bends, or areas where the soil puts more pressure on the plumbing.
Even if you don’t hear anything, check common problem areas:
- Near trees, where tree root intrusion may have pushed into the pipe
- Along the path from the water supply to your home
- Around irrigation systems, outdoor sprinkler systems, or hose bibs
- Places where the soil has shifted or settled
Digging Smart (Call First)
Once you’ve narrowed down the leak location, you might consider digging to expose the pipe. But only dig if you’re confident about the location. Shoveling blindly and unnecessary digging can damage the pipe more or cut into other lines like cable or gas.
Before you dig, call your local utility marking service. Most places offer a free 811 service that marks underground lines so you don’t hit anything dangerous.
If you do start digging, take it slow. Use a small hand shovel and dig carefully around the suspected area. Look for moist soil, mud, or an obvious crack in the pipe. Sometimes the pipe will have a tiny hole; other times, it may be completely split. If you feel the situation might call for extensive excavation it's time to get professional assistance.
When It’s Time to Call a Pro
Not all leaks are easy to find. If you’ve checked the meter, walked the yard, and still can’t get a precise location, it may be deeper underground or under concrete. Professional leak detection employs the use of specialized equipment like acoustic leak detectors, thermal imaging cameras, or pressure testing to pinpoint the problem without tearing up your yard.
Some pros use tracer gas—a safe, odorless gas that’s pumped into the pipe and tracked with a sensor above ground. This helps spot very small leaks that don’t leave visible signs.
If the leaky pipe is old or made of materials like galvanized steel or clay, the plumber may suggest replacing it instead of patching one spot. Repairs on a failing pipe often reveals another issue later.
FAQ
How do I know if the water leak is in my yard or under my house?
Turn off the main shut-off valve to your house. If the water meter keeps spinning, the leak is likely between the meter and your house—in the yard. If it stops, the leak is probably somewhere inside.
Does soil type affect how easy it is to find a leak?
It does. Some soil types show minimal signs while others may have big damp spots. Sandy soil drains quickly, so leaks may not cause surface puddles. Clay holds water longer, so even a small leak might create soggy spots. Rocky or compacted soil can make sound detection harder too.
