A leak you can't see costs the most.
Household leaks waste nearly 10,000 gallons of water a year on average (EPA WaterSense) — and a pinhole inside a wall can run for months, feeding mold and rot, before the first stain shows up.
Warning signs: a water bill that jumped, the meter spinning with everything off, warm spots on floors, musty smells, or a pool losing more than ¼ inch a day.
Call early. Finding it this week instead of this winter is the cheapest plumbing decision you'll ever make.