How to Find a Slab Leak

Use the proper procedure to locate a slab leak to limit the amount of concrete breaking and removal. Sometimes the first indication of a slab leak is a high water bill; for example, a homeowner receives a higher-than-normal bill without having intentionally used extra water. This puts the homeowner on the hunt for a leak. Finding the leak is not always a simple task. A professional plumber may be needed to complete the task if do-it-yourself methods fail.

Pipes under the slab may break from stress or age.
  1. Search for warm or cold spots on the floor. If no wet spots are apparent on the floor, feel carefully for spots which are warmer or colder than the surrounding area. If hot water pipes are leaking, the floor will be warmer. If cold water pipes are leaking, the floor will be slightly cooler.

  2. Find the pipe layout under the slab. Use a metal detector if the pipes are copper or other metals. A special device is available for finding other types of piping such as PVC.

  3. Listen along the piping lines. With a listening device, listen for changes in the sounds along the pipes. This can indicate where the water is leaking.

  4. Turn off the main water source to the home.

  5. Jackhammer the slab at the point indicated by cold or warm spots or by listening to the area of the leak. The leak may not be precisely at the point indicated but should be in close proximity, eliminating the need to destroy any more concrete than necessary.


  • Do not use a jackhammer without experience.

About the Author

Sidney Johns began her writing career in 1993 after moving to Florida. The former teacher and surgical technician worked in the home improvement industry prior to earning a Bachelor of Science in education from Indiana University. While on hiatus in 2004, Johns studied holistic healing and organic growth and gardening.