Slab leaks 101: Warning signs, causes, repairs for homeowners

Slab leak warning signs, causes, and finding the right professional for successful reparation

A slab leak is a leak under the foundation (or concrete slab) that your home is built upon. While these leaks can seem small and insignificant at first, they can lead to significant damage and costly repairs.

If left unattended, slab leaks can saturate the soil under your home, making your floors uneven and slowly sinking the building into the ground. To avoid this disaster, let’s take a look at some things that can either help you avoid a slab leak or repair any damage caused as a result of the slab leak.


  • Higher electric or gas bills
  • Little or no hot water
  • Constant sound of running water even when the water is off
  • Wet spot on floor
  • Standing water in yard
  • Warm/hot spots on floor
  • Mold under the flooring or carpet
  • Low water pressure in the shower and sink
  • Soggy spots near the home’s foundation


Common causes to an under slab plumbing problem:

  • Cast iron pipes corroding or rusting over time. These are common in homes built prior to the mid 1970s. Older homes, which are often installed with copper or galvanized steel pipes, are more at risk. Corrosion, for example, is more likely to happen over time. Extended periods of stress or pressure on pipes can also lead to slab leaks.
  • Natural elements such as tree roots penetrating or disrupting under slab pipes or movement of the foundation from rainwater, mud, earthquakes, or something else. This could also go in hand with natural abrasion from pipes rubbing against concrete, gravel, other materials, or other nearby pipes, the constant friction can cause them to gradually wear down and ultimately spring leaks.
  • Foundation adjustment or repair.
  • Seals between pipes breaking.
  • Poor-quality Pipes. If your water pipes were kinked, bent, or dented in any way during installation, the affected areas could cause the pipes to leak and potentially burst because of the abrasive properties of water flowing by over time.


Slab penetration:

This method uses a jack hammer to dig a hole directly to the leak. This usually means lots of noise and the possibility of having to replace damaged floor coverings – carpet, tile, linoleum, laminate, wood, and more. So if you’re considering fixing a leak using this method, don’t forget to take replacement costs into consideration.


This method requires tunneling a path from underneath the slab and is much less invasive. With tunneling, there is no need for interior demolition. In instances where multiple leaks exist, tunneling is usually the most cost-effective repair solution. When tunneling is involved, the crew you are using should properly excavate the work area and work in compliance with OSHA standards.


Your home is an investment. Make sure you pay close attention to any signs of a water leak, even if it isn’t in the most visible spot.

For more information, check out this guide to under slab leak repairs. If you have anymore plumbing questions, feel free to contact us here.

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