How to Find and Fix Leaking Pipes Under a Slab Foundation

It’s no secret that pipes, water and sewer lines eventually begin to erode and leak. This happens with normal wear and tear and is inevitable in most homes.

Many people assume that repairing a leaky pipe beneath a slab is a difficult task. However, it’s not as hard as you might think. Locating and gaining access to the pipe can be tough, but once you know the general area of the leak and can cut your way through the slab, repairing the pipe is simple.

How to Tell if You Have a Leak Under a Slab


Luckily, there are several signs that indicate a leaking pipe under your slab:

  • The first indicator is the presence of water or damp spots on your floor. Leaking hot-water lines can also create warm spots on your floor. Walking around with bare feet inside your home can help you identify the location of any lines that are leaking because you’ll feel the heat through the floor.

  • A second situation that can alert you that your water lines are leaking is the sound of rushing water underneath your floor. If it seems like a faucet is turned on beneath your house (and you know there isn’t actually a faucet on somewhere), you likely have a leak in your piping.

  • Finally, a significant increase in your water bill could be a sign of a leaking pipe. Since a broken line runs continuously, your water bill will rise. If you notice an increase that you can’t explain, either your water company is taking advantage of you, or you have a leak!

Sewer lines

Leaking sewer lines are a different issue. They are more difficult to detect and often go unnoticed until there are visible signs which include damage to your foundation or domed (raised) sections of flooring. If you suspect a leaking sewer line, check your foundation for “heaving,” which occurs when the slab swells enough to actually lift the entire structure.

Elusive leaks

Some leaks are difficult to find and require the use of specialized listening devices (sonar), infrared cameras, or helium detection equipment. After turning off the water completely, air is pumped into the lines. This forces out any remaining water, so the plumber can listen for air escaping from the damaged pipe.

How to Fix a Slab Leak

Once the leak is identified, a plumber can evaluate the situation and the location of the leak. At this point, a plan is configured and put into place. In some cases, it’s better to re-plumb the affected section, while other times new new piping throughout the the entire house will be necessary. Attempting to repair old, galvanized plumbing is typically a waste of money, as dated pipes will continue to spring new leaks as they age.

Gaining Access

Once the leak is located, jackhammering a hole in the floor is required to access the pipe. Finished flooring will be removed in order to expose the concrete. Opening a slab will create a significant amount of dust, so taking the appropriate steps to cover and or remove furniture and valuables is important. Once the hole is cut, dirt is removed, providing access to the leaking pipe.

Repairing Damaged Water Lines

The most common type of pipe used for water lines under slab foundations is copper. Unfortunately, as copper pipes age, they are prone to wearing thin and springing leaks. Before beginning the repairs on a section of pipe beneath a concrete slab, consideration should be given to re-piping, rather than using a temporary fix.

Should you decide to repair the copper pipe, rather than replace, it’s a fairly easy procedure. A hacksaw or tubing cutter can be used to cut out the damaged portion. The next step is to simply replace it with new tubing and copper couplings before soldering it into place to repair the flow. The pipe will be buried, concrete replaced and floors fixed, getting you back to normal life.

Repairing Sewer Lines

While it’s possible to repair a leaky water pipe on your own, fixing a leaking sewer line may require the services of a plumber. Before you decide to take on this kind of project yourself, consider the type of pipes that were used, along with the health-related issues involving exposure to human waste.

Depending on the age of the home, sewer lines may be cast iron, clay, or even PVC. Special rubber couplings are ideal for connecting different types of pipes, but they are not recommended for use underneath concrete slabs. The rubber boots deteriorate over time, especially when used outdoors. Working directly with a plumber will empower you to become educated on the situation and give you choices that work best for your home.

To find out more about your options for repairing a slab leak or to schedule an appointment,

CALL (888) 660-0471 or