What a slab leak is
A slab leak is a leak in a water line that runs under or through the concrete slab your house sits on. It can be a hot or cold supply line. In the Las Vegas valley, slab homes are the rule. Caliche, the hard cemented layer under much of the valley, is the top reason homes here rarely have basements, so builders pour slabs and run lines below them.
The water from a slab leak does not drain away into a basement. It pushes up through cracks and joints and spreads under tile, carpet and wood.
Eight signs, from most to least obvious
- Wet or damp flooring with no spill to explain it.
- A warm spot on tile or wood, a sign of a hot water line.
- Base or the bottom of a wall that swells, stains or peels.
- A musty smell that will not go away.
- The sound of running water when nothing is on.
- A water bill that jumps for no reason.
- Lower water pressure at faucets.
- Cracks in tile or wood that appeared or grew.
Many top pages stop at a list like this. The step that matters is checking whether water is leaving the system at all.
The one hour water meter test
- Turn off every faucet, the washer, the dishwasher, the ice maker and the irrigation timer.
- Find your water meter, usually in a box near the curb. Note the reading or watch the small leak dial.
- Wait one hour without using any water.
- Read it again. If it moved, water is leaving somewhere.
The test does not tell you where. A leak detection plumber finds the spot with listening gear and pressure tests. It does tell you to call one now.
Why the valley ground makes this urgent
North Las Vegas has a long record of ground movement. Groundwater pumping caused land to sink and fissures to open, and areas near North Las Vegas Airport sank up to 2.6 feet from 1963 to 1980, per 1989 state data. In 2018, an engineering report flagged expansive clay near Cheyenne Avenue and Simmons Street, and the advice was to keep water away from it. In Henderson, caliche that varies from spot to spot can cause uneven settling.
A slab leak puts water exactly where none of that advice wants it.
Does insurance cover it
Policies differ, and this is where you need to read yours. Many home policies treat sudden discharge from plumbing as covered, and the Insurance Information Institute says that is true of most forms except HO-1 and HO-8. Many policies also separate the cost of the pipe repair from the damage it caused, and some cover tearing out and replacing part of the floor to reach the pipe. A slow leak that went on for months can be treated as wear. Ask your agent about access and tear out wording.
After the plumber fixes the line
The line is fixed. The flooring and walls above it are still wet. Tile set on a slab can hold water under it. Wood floors cup at the edges. Carpet pad holds water like a sponge.
- Readings across the slab and the walls next to it find where the water went.
- Flooring that cannot be saved comes up.
- Air movers and dehumidifiers run until readings match a dry room in the same house.
- Cupped wood is not sanded until moisture is back to normal, or it crowns later.