Underground Water Line Leaks: How to Spot Them Before They Get Worse

Water line leaks are one of those problems you don’t really think about… until it becomes a major one. And unfortunately, most water line leaks happen underground, where you can’t see them. That means the damage can go unnoticed for weeks or even months before you realize something’s wrong.

At Horn’s Backflow and Plumbing Service, Inc., we get a lot of calls from customers who say, “I had no idea this was happening until I saw my water bill!” So in this post, we’re going to walk you through what to watch for, why these leaks happen, and what to do next if you suspect something's going on under the surface.

🚩 First, what are the warning signs of an underground water leak?

Even if you can’t see the leak, there are still some clear signs that your main water line might be in trouble:

• Your water bill suddenly spikes, but you haven’t changed your usage.

• Wet spots or puddles appear in your yard, especially when it hasn’t rained.

• Water pressure feels lower than usual, or it fluctuates when you’re using different fixtures.

• You hear water running when everything’s turned off.

• Your walls or floors feel damp, or paint starts bubbling for no reason.

These issues might seem minor at first, but they often mean that water is escaping somewhere it shouldn’t be, and the longer it goes on, the worse the damage gets.

🌳 So… what causes underground leaks in the first place?

There are a few common culprits behind underground water line leaks:

• Aging pipes — Many older homes still have galvanized steel or aging copper lines that corrode over time.

• Shifting soil — Earthquakes, erosion, or even nearby construction can cause pipes to crack or disconnect.

• Tree roots — Yep, roots love water and will actually grow into your pipes if they find a weakness.

• Poor installation — If the line wasn’t installed properly from the start, problems can show up years down the line.

• High water pressure — Too much pressure can put stress on your system, especially if the materials are older.

 Here’s how we find the problem without destroying your yard

The good news? You don’t need to start digging to find a leak.

At Horn’s, we use non-invasive leak detection tools like:

• Acoustic listening devices (yep, we actually listen for the leak!)

• Thermal imaging to detect moisture behind walls or under floors

• Pipe tracing equipment that maps out your water lines

• Pressure testing to see if the line is losing flow

Once we find the problem, we’ll show you exactly what’s going on and explain your options, whether it’s a quick repair or a full (trenchless) replacement.

Let’s fix it before it floods

If you’ve noticed any of the signs we mentioned, don’t brush them off. Hidden water line leaks are sneaky and expensive—but they’re fixable, especially when caught early.

📞 Give us a call at Horn’s Backflow and Plumbing Service, Inc., and we’ll come out to inspect your water line, locate the problem, and take care of it before it gets out of hand.