Because foundation slab leaks occur under concrete, they often remain hidden until significant structural water damage has occurred. Watch for these 5 telltale signs:
- Hot or Warm Spots on Floors: If a particular tile, hardwood plank, or carpet section feels noticeably warm beneath your feet, a hot water copper line is leaking under the slab.
- Unexplained Water Bill Spikes: If your monthly DWP or local water bill doubles with no change in household usage, hundreds of gallons are leaking under your home daily.
- The Water Meter Test: Turn off all faucets, toilets, and ice makers. Check your outdoor water meter. If the low-flow indicator triangle is spinning, pressurized water is escaping.
- Sound of Running Water in Quiet Rooms: Hearing a steady hissing or trickling sound behind baseboards when no fixtures are in use.
- Baseboard Mold, Damp Drywall, or Floor Buckling: Moisture wicking up through concrete into drywall and wood framing.
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These guides are here to help you understand what's going on — not to replace a real inspection. If something feels off, it's worth a call before it becomes a bigger problem.