The problem with hidden water leaks inside walls is the “hidden” aspect. Household water supply lines routed through walls are usually 1/2-inch or 3/4-inch pipes under a typical residential water pressure of 40 to 60 pounds per square inch. A total rupture of a supply line inside a wall becomes conspicuous very rapidly and typically warrants emergency service by a qualified professional plumber.

On the other hand, slow seepage and drips due to leaky pipe joints, internal pipe corrosion, and other small sources may continue unnoticed and unabated for some time. Eventually, however, these initially minor leaks may progress to a major rupture that can’t be ignored.

Unseen water leaks inside walls don’t mean that significant damage isn’t already ongoing. Potential consequences of ongoing water leaks include:

• Rotted internal wooden structure
• Deteriorated drywall
• Ruined insulation inside the wall
• Damage to electrical wiring and other components
• Toxic mold growth that spreads contamination to other parts of the home

Here are five initially subtle signs that may indicate water leaks inside walls:

• • The odor is musky. Water-damaged wood, drywall, and insulation in the wall cavity provide a perfect breeding ground for toxic mold. Typical signs of mold contamination inside walls include a pungent musty odor that permeates the immediate area and doesn’t disappear.
  • Mold on walls is visible. Drywall absorbs moisture. Mold can grow on the exterior surface of a wall if moisture absorbed through hidden leaks inside the wall permeates the material. The mold on the wall may appear as a mottled discoloration.
  • Stains without explanation. Likewise, water infiltrating from the inside of the drywall may cause noticeable stains or a darkening of the surface.
  • Remove paint or wallpaper by peeling it off. As a result of chronic moisture present inside the wall, paint deteriorates and wallpaper adhesive dissolves. Water leaks inside a wall can be indicated by peeling paint or wallpaper.
  • Deflation of the wall. Water absorbed through hidden leaks may cause the wall to sag or bend as it spreads throughout the material. After that, the drywall may be structurally unsound and at risk of collapsing.