Slab Leak Signs & Causes
Signs of a Slab Leak — What to Look For
Slab leaks develop slowly and quietly. Most homeowners notice a combination of small clues before there's ever a visible puddle.
Physical Signs
- A warm or hot patch on the floor, most noticeable on tile or concrete
- A wet or damp area on flooring with no obvious external water source
- Cracks in flooring, baseboards, or nearby drywall
- A musty or mildew smell near the floor with no visible cause
- The sound of running or hissing water beneath the floor when fixtures are off
Usage & Utility Signs
- A water bill that's noticeably higher with no change in household usage
- The water meter continuing to move when every fixture in the house is off
- Lower-than-normal water pressure at a fixture that previously ran fine
One Symptom Isn't Proof
Any single sign on this page can have another explanation — a warm floor might be sunlight or a heating duct; a water bill spike might be an irrigation timer left running. That's exactly why detection equipment is used rather than guessing from symptoms alone: it confirms whether a slab leak is actually present before anyone decides to open a floor.