Short answer
The main slab leak warning signs are an unexplained jump in the water bill, a warm spot on the floor, the sound of running water with everything off, and damp carpet or baseboards along interior walls. Confirm by checking whether the water meter moves when nothing is running.The meter test
Turn off every fixture and appliance that uses water, including irrigation and the softener. Look at the meter's leak indicator, usually a small triangle or dial. If it's moving, water is going somewhere.
Common signs
Slab leaks show up differently depending on which line is leaking.
- Warm floor: likely a hot-water line
- Damp carpet edges or swollen baseboards
- Cracked tile or grout that feels wet
- Low water pressure
- Water heater running constantly
Why they're common in the Valley
Most homes here sit on slabs with supply lines below or inside the concrete. Hard water and older copper lines contribute, and soil movement can stress pipes over time.
What happens next
A plumber locates the leak and repairs it through the slab or reroutes the line overhead. A restoration company dries the flooring, baseboards and wall bottoms that water soaked from below.
Questions
Is a reroute better than a spot repair?
It depends on the pipe's condition. One leak in old copper often means more are coming, which is why many plumbers recommend rerouting. A single failure in newer pipe may be spot-repaired.
Can a slab leak cause mold?
Yes. Water rising into pad and wall bottoms can stay hidden long enough for mold to grow, so drying should be measured and documented.
This guide is general information for Arizona homeowners, not a substitute for an on-site assessment or your insurance policy wording.