Guide
Signs of a Slab Leak in Las Vegas
A slab leak is a leak in a water line running under a concrete foundation. Common signs are a warm patch on the floor, running water audible with everything off, an unexplained jump in the water bill, and a meter that keeps moving when no fixture is open.
A slab leak is a leak in a water line running under a concrete foundation. Common signs are a warm patch on the floor, running water audible with everything off, an unexplained jump in the water bill, and a meter that keeps moving when no fixture is open.
Last updated 2026-09-17. Published by Las Vegas Plumbing.
Why valley homes are exposed
Las Vegas Valley housing is overwhelmingly slab on grade: a concrete foundation poured directly on the ground, with no basement and no crawl space.
That construction is well suited to the climate and it has one consequence for plumbing. Water lines running through or under the slab are inaccessible, so a leak there has nowhere visible to go. It saturates the ground under the house instead, and everything you notice is indirect.
This is why the signs matter. On a home with a crawl space you would see water. Here you see a symptom.
The six signs
Any one of these is worth checking. Two or more together makes it likely.
| Sign | What it usually means |
|---|---|
| A warm patch on the floor | A hot water line leaking under the slab |
| Running water audible with everything off | Water escaping somewhere under pressure |
| Water bill up with no change in use | A continuous loss somewhere on the property |
| Damp or discoloured flooring in one spot | Moisture coming up through the slab |
| Cracks appearing in floors or walls | Soil movement from saturation beneath |
| A musty smell with no visible water | Long term moisture under floor coverings |
The meter test you can run yourself
This takes about twenty minutes and it is the single most useful thing a homeowner can do before calling anyone.
Turn off every fixture and water using appliance in the house. Find the water meter, usually in a covered box near the street, and note the reading, including any leak indicator dial. Leave everything off for twenty to thirty minutes and read it again.
If the reading moved, water is being lost somewhere. That does not prove it is under the slab, but it does prove there is a leak, and it turns a vague worry into a fact worth acting on.
Rule out irrigation first
Before assuming the worst, isolate the irrigation system if your property has one. A large share of unexplained water loss in this valley is irrigation rather than household plumbing, and a cracked lateral or a stuck valve loses a great deal of water into landscaping without any surface sign.
If closing the irrigation supply stops the meter, the problem is in the irrigation and you have avoided the expensive investigation entirely.
What happens next
Detection narrows the location before anything is opened, using isolation and acoustic equipment. The point is to open one hole in the right place rather than several in the wrong ones.
Once located, there are usually two repair routes: open the slab and repair at the failure, or abandon that section and reroute the line. Repair is cheaper now. Rerouting costs more and takes that run out of the ground permanently, which often ages better on a line that has already failed once.
FAQ
Common questions
Can a slab leak fix itself?
No. A leak that appears to stop usually means a valve closed somewhere or the line drained. The failure has not repaired itself.
How serious is a slab leak?
Serious enough to act on promptly. Continuous water under a foundation saturates soil, can affect the slab, and wastes a substantial volume of water in the meantime.
Will my insurance cover a slab leak?
That depends on the policy and usually on the cause. Documentation of what failed and why is what an insurer will ask for, so it is worth having.
Can a slab leak be repaired without breaking the floor?
Sometimes, by abandoning the failed section and rerouting the line overhead or through a wall. It costs more than a spot repair and avoids opening concrete.
Sources
Where these facts come from
Related services
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Whole house or one run, in copper or PEX, with the disruption explained up front.
Repiping explainedStill not sure what you are dealing with?
Describe the symptom and we will tell you what it usually means before anyone comes out.