If a slab leak is suspected there are a few different methods used to confirm it:

Visual inspection: sometimes you can tell just from looking at the water meter.  You may see wet planters around your home and water inside your home near the base boards, for example.

Thermograph inspection: locates the leak by comparing the temperature of the affected area to the surrounding area.  Cameras that can detect Infrared radiation are used to find the areas that are warmer or cooler, which may be the location of water loss.  It can also be used to identify water in locations that are hard to check, such as inside walls and the roof.

Ultrasound inspection: uses sound waves to identify the location of the leak.  This can be done in two ways: 1) by identifying the sound of water coming out of the pipe, and 2) by passing air through the line and then locating the sound made by the air as it escapes from the line.

Helium detection: helium is passed through the lines and escapes through the leak.  A tool is used to find the place where the helium is escaping.  Helium molecules are small enough to fit through even the tiniest holes, and it does not react with whatever is in the pipe so this method is useful when adding liquid to a pipe is not desirable.

These can be used separately or together to help identify the leak.

The alternative is to just start digging and tearing up the ground and hoping you find it, and is often done by unskilled workers. That’s not the way you want.

The best option for fixing a slab leak will depend on the nature of the problem.  In some cases a new pipe can be installed without having to tear up the slab to get access to the faulty pipe.  This option is called a reroute and involves adding a new pipe in the ceiling and walls to replace the one below the slab.  This option can be rather intensive and will require adding new drywall when everything is done.  In other cases, the leaking pipe may need to be accessed directly which requires digging through the slab itself.  This can be an involved project which can take a while a make quite a mess.

Rather than replacing the leaking pipe, it’s also possible to repair the leak with epoxy which, if done correctly, should also prevent future leaks.  This option can be cheaper, easier, and faster than the ones mentioned above.

Older pipes may be made out of a material like polybutylene that is more likely to develop holes over time.  If your house was built after the mid 90s chances are you don’t have that kind of pipe, as it is more common now for PVC and copper to be used.  PVC is pretty common; you’ve probably see it at the hardware store.  They are the long white pipes.  The problem with PVC, however, is that it can grow bacteria.  Copper is harder to install and may become corroded.

So depending on the type of pipe involved your repair options may differ.

If you keep having issues, a solution may be to replace your older pipes with newer, more resistant materials.

Slab leaks are caused by small holes that form in the pipes under your concrete foundation (if they form above the concrete they are called pinhole leaks, and most often occur in the wall or ceiling).  There are a few things that can cause these holes, including:

– The foundation shifting

– Too high of water pressure

– The chemicals in the water reacting with the pipes

– The chemicals in the soil reacting with the pipes

– Low quality work/materials/supplies

– Something puncturing the pipes, such as a nail from another project

– An improperly wrapped pipe that comes into contact with something else and wears away over time

– Movement of the pipes.  Since pipes can move a bit when water flows through them, and hot water pipes may expand and contract as the water changes temperature, friction can eventually cause a hole to form.

Some experts recommend that you re-pipe your home if you have experienced more than two previous slab or pinhole leaks.