A slab leak is a water line that has started leaking beneath the concrete slab your home sits on. Because the pipe is buried, the leak can run for weeks or months before you notice. The good news is that your home almost always signals the problem early if you know what to watch for. Catching it at the first sign means a smaller, cheaper repair and far less risk to your floors and foundation.
The 7 warning signs of a slab leak
A warm or hot spot on the floor
When a hot-water line leaks under the slab, it heats the concrete above it. If one patch of floor is noticeably warm, especially on tile, it is a classic slab leak sign.
A water bill that suddenly jumps
A slab leak runs 24 hours a day. If your bill spikes with no change in how much water you use, water is escaping somewhere you cannot see.
The sound of running water
Turn off every faucet, toilet and appliance. If you still hear water moving in the walls or floor, a hidden leak is a likely cause.
A drop in water pressure
When water escapes before it reaches your fixtures, pressure falls across the home even though the supply line is fine.
Cracked, damp or warped flooring
Moisture rising through the slab can lift tile, warp wood, dampen carpet, or create visible cracks in the floor.
A musty or mildew smell
Trapped moisture under floors and inside walls creates the damp conditions mold needs, often producing a musty smell before anything is visible.
A meter that keeps spinning
With all water off, check your water meter. If the dial keeps moving, water is leaving the system, frequently under the slab.
How to check for a slab leak yourself
You can run a simple test before calling a plumber. Turn off every water-using fixture and appliance in the house. Then find your water meter and watch it, or note the reading and check again in 20 to 30 minutes. If the meter is still moving or the reading has changed with everything off, water is escaping somewhere in your system. That test confirms a leak exists, but it will not tell you where it is. For that, you need professional slab leak detection.
Is it a slab leak or another plumbing problem?
A slab leak usually shows up as water loss with no visible source: a high bill, a warm or damp floor, running-water sounds and low pressure, while your faucets and visible pipes look perfectly normal. If you can see water under a sink, around a toilet or at a fixture, that is a different, more straightforward repair. When the loss is invisible, suspect the slab, and have it confirmed with a pressure test and acoustic detection.
What to do if you notice the signs
Do not wait and hope it passes. A slab leak only gets worse and more expensive the longer it runs. If you spot any of the signs above:
- Run the meter test to confirm water is escaping.
- If the loss is significant, shut off your main water valve.
- Call a licensed slab leak specialist for professional detection.
- Avoid breaking into the concrete yourself. Accurate detection means only a small area ever needs to be opened.
Understanding what causes slab leaks in Prescott homes can also help you judge your risk, especially with the area's hard water and aging copper lines.
Think you have a slab leak in Prescott?
We have been finding and fixing slab leaks across Prescott since 2014. If any of these signs sound familiar, call (928) 470-4470. We will confirm whether it is a slab leak, find it without tearing up your floor, and give you a clear repair plan.