A slab leak is a leak in a water line under your home's concrete foundation. Because the pipe is hidden, slab leaks can run for a long time before anyone notices.
7 signs of a slab leak
- A water bill that jumps with no change in how you use water
- The sound of running water when everything is off
- Warm spots on the floor (a sign of a hot water line leak)
- Damp carpet or warped wood floors
- Musty smell or mold near baseboards
- New cracks in floors or walls
- A water heater that runs constantly
The meter test
- Turn off every faucet and water-using appliance in the house.
- Look at your water meter. Many meters have a small triangle or dial called the leak indicator.
- If it's moving with everything off, water is going somewhere.
- Write down the reading, wait an hour without using water, and check again.
How slab leaks get fixed
First, the leak is located as precisely as possible. Then there are usually three options:
- Spot repair: open the slab at the leak and fix it
- Reroute: run a new line through walls or the attic and abandon the leaking line under the slab
- Tunnel: reach the leak from outside under the slab
The best choice depends on where the leak is, the type and age of the pipe, and whether more leaks are likely.