Shoutout to the plumber who found a leak under the foundation
I nearly bought a house with a hidden water issue. The standard inspection report came back clean, but something felt off. I called in a plumber for a second opinion, and he spotted corrosion under the slab. That extra step kept me from a nasty surprise after moving in. Always get a specialist to check the plumbing before you sign anything.
Doubt it's always that big a deal though. Honestly some small leaks under a slab can go for years without real trouble. They might just make your water bill a bit higher. Tbh I feel like sometimes these inspections scare people over stuff that isn't urgent. Sure, get it checked, but not every drip means a disaster.
Had a friend who ignored a small leak under their slab. Two years later, the foundation started cracking from all the moisture. Cost them over ten grand to fix the mess. Now I always tell people to get it checked early, even if it seems minor.
But what if that slow leak starts growing mold under your floors? Spores can get into your air vents and really mess with your air quality. Like @jade_reed said about roots, they can break pipes and let soil in that mold feeds on. Now you've got a health hazard, not just a water bill problem.