Slab Leak Basics

4 August 2020
 Categories: , Blog


Not all foundation troubles are caused by shifting soils or high water tables. In some cases, particularly with slab foundations, the actual cause of foundation damage is in the plumbing. Slab plumbing leaks can also lead to cracked, crumbling, or shifting foundations that require repair. The following guide can help you better understand the damages caused by slab leaks and what you can do about it.

Foundation Affects from Slab Leaks

When a plumbing leak occurs beneath the foundation, moisture will collect in the soil beneath the concrete. This causes the soil to expand as it absorbs moisture, which will uplift the foundation and cause damage. If there are small cracks already present in the foundation, the water may also seep into these cracks and cause them to become larger. This can also lead to foundation damage.

Signs of a Slab Plumbing Leak

If your water usage is going up on your meter but you aren't using more water in the household, you likely have a plumbing leak. Often, this leak is under the foundation, especially if you have no signs of a leak elsewhere. Sometimes the moisture from the leak comes up through foundation cracks, so you may end up with damp or moldy carpet. There are also sometimes signs of foundation damage, such as doors no longer closing as the house sinks or rises from the foundation damage.

Verification Method for a Slab Leak

A plumber or foundation contractor can verify the presence of a slab leak by performing a hydrostatic test. This is basically a pressure test of your plumbing lines. If the pressure is low, then there is a leak somewhere in the lines. Your plumber will need access to the cleanout lines for your plumbing to perform the test. If your home is not equipped with cleanout lines, then they will remove a toilet and use the waste pipe as a cleanout line in order to perform the test.

Slab Leak Repair Options

The method for repairing the leak depends on the location and severity of the leak. In some cases, the old pipes must be removed and replaced. If the pipes can't be easily accessed, then the foundation must be opened up to give it access for the repair. Trenchless repair may be possible depending on the location of the leak. Once the leak is repaired, then the foundation contractor will repair any damage to the foundation.

Contact a plumber or foundation contractor like Du-West Foundation Repair in your area to learn more.