Groundwater or Plumbing Leaks through a Concrete Slab

Leaks beneath a concrete slab on grade most commonly occur due to groundwater intrusion or plumbing failures. Both groundwater and pressurized plumbing leaks tend to result in more severe and localized damage than that which commonly results from vapor drive through a concrete slab on grade.

Groundwater issues can become more or less severe with raising and lowering of the water table. Higher exposed ground and heavy rains near the building can contribute to the pressurization of groundwater beneath an adjacent slab. Other more common drainage issues, such as misdirected gutters or exterior grade sloping towards the building can also exacerbate a problem.

Pressurized plumbing leaks usually manifest with as more severe because such a leak can continuously release a significant volume of water under pressure. If such leaks go unnoticed for a period of time, soil erosion can occur beneath the slab. This in turn can result in undermining of the slab which can lead to structural damage from settlement.

The cause of such a problem can be more difficult to diagnose and correct, because conditions are hidden beneath a concrete slab on grade. A first step may be to confirm or exclude a potential plumbing supply line leak. Consider when the problem manifested and check recent water usage. Turn off all water use in the building, then check the water meter if present. Water still flowing through the meter would indicate a leak. A worsening condition after heavy rains may indicate groundwater seepage.