How to Detect a Leak in a Concrete Slab

A slab leak is a water leak within the foundation of a home, which can often result in water damage, flooding, and structural damage. For homeowners, it’s a complicated and expensive repair, and like many plumbing problems, it’s best to catch the issue early on. Slab leaks occur for a number of reasons including inept craftsmanship, aged pipes and foundation, high water pressure, tree roots and uneven soil. While the causes of slab leaks are often out of a homeowner’s control, they can always be aware of the signs of a slab leak to prevent further damage. If you notice a sharp increase in your water bill or experience irregular low water pressure, there may be a leak. Leak detection is a difficult process especially in larger homes, and you may need the assistance of a professional plumber. Before you call a plumbing company, however, there are some steps you can take to narrow down the leak’s source.

1. Searching for cold or hot spots
   After sensing that there is a leak in your home, your first action would be to look for cold or warm spots on the floor. In case hot water pipes are leaking, you are likely to find a hot spot on the floor. On the other hand, you will feel cool spots on the floor when the leakage is being caused by cold water pipes. Also, you should be on the lookout for any wet spots on the floor as this could be indicative of slab leakage.
2. Checking the pipe layout
   The next task would be to check the pipe layout under the leaking spot beneath the slab. If possible, you should employ the use of a metal detector to detect metallic pipes such as copper. In case the pipes are PVC, then you would need a special device to detect them.
3. Look for cracks or mold
   While looking for a foundation leak, it is also important to look for any molds or cracks on the floor. In the former’s case, any detection of moisture is always an indicator of a leakage underneath. Cracks could also be an indication that water is leaking underneath the slab.
4. Taking pictures of the slab
   Take pictures of all the slabs in the home. Thereafter, the pictures should be processed or opened on a monitor. You can then analyze each of these pictures carefully for any changes in the shades of paint. Also, these pictures could alert you to minor damages caused by a leakage. It is amazing how much detail will show in a photo compared to the naked eye.  Take a photo with the flash on and with the flash off.   You can modify the brightness when viewing by using a program like Picasa to enhance.
5. Use listening device
   A listening device would also be a necessary accessory when detecting a leakage under your slab. In this case, the listening occurs along the piping lines where you try to hear running water for any changes. Leakage occurs when there are changes in the sounds emanating along the pipes. Thereafter, you should turn off the main source of water to the home.
6. Jackhammering
   After ascertaining the point of leakage, the nest step would be to jackhammer as close to the leak’s source as possible. Granted, this may not be the exact point of leakage, however, being that it is in close proximity to the leakage point. You can avoid creating a lot of damage to the concrete by scoring the area with a concrete saw, or circular saw with a concrete blade, and jackhammering inside the scored area.  This will give you a clean line to repair.  FYI: cutting concrete is perhaps the messiest (dustiest) home improvement job you will do.