Slab leak warning signs. Catch it early, fix it small.
A slab leak is a water line leaking under your concrete foundation. Caught early, it's a small, targeted repair. Caught late, it's a ruined floor and a big mess. Here's how to spot one — and the 5-minute test that confirms it before anyone picks up a jackhammer.
6 signs of a slab leak
If two or more show up, do the meter test below:
- Hot spot on the floor — warm tile or concrete
- Sound of running water when everything's off
- Water bill jumped for no clear reason
- Damp carpet or baseboards that won't dry
- Low water pressure that came on gradually
- Water heater runs constantly — feeding a hot-line leak
Confirm it in 2 steps.
These two tests tell you whether you actually have a leak. Do them before anyone talks about breaking concrete.
The water meter test
Turn off everything — every faucet, every appliance, every irrigation valve. Then go to the water meter (usually at the curb), lift the lid with a screwdriver or meter key, and watch the small dial or triangle for 10 to 15 minutes. If anything moves with everything off, water is flowing somewhere it shouldn't. That's a leak — confirmed, no guessing.
Check hot vs. cold
A warm spot on the floor points to a hot-water line leak. Walk the floor barefoot and find the warmest spot, check whether the water heater is cycling on constantly, and touch the hot water pipe where it leaves the heater. Hot spot plus a heater that never rests means the hot line. Meter moving with no hot spot anywhere means it's the cold line — or irrigation.
Here's the truth: jackhammering blind is how cowboys work.
A real plumber pinpoints the leak first. Here's what that means for your floor.
Proper leak detection pinpoints it first
Electronic listening equipment and thermal imaging find the leak — often within inches — before any concrete is touched. The hole goes exactly where the leak is, not across your whole living room.
A pinpointed leak means a small patch
One square foot of concrete opened and patched beats a trench through your floor. Detection is what keeps the repair small — and the patch is a lot easier to make disappear.
If the meter moves, it's real
The meter test takes five minutes and it's definitive. Anyone who wants to start breaking concrete before that test is done is someone you send home. Call us — we'll run the detection and show you exactly where the leak is before we open anything.
When to call a plumber.
Days, not months — slab leaks get worse every day they run. Call if:
The meter moves with everything off
That's a confirmed hidden leak — no more guessing needed. Next step is electronic leak detection to pinpoint it, and that's our job. Call (818) 669-9019 any time.
There's a hot spot on the floor
Hot-line slab leaks waste hot water around the clock and get worse fast — your water heater is working overtime feeding it. Don't wait on this one; get it located and fixed.
Damp spots are spreading
Moisture under flooring breeds mold, and the longer it runs, the bigger the damage and the repair. If the line itself is old and failing in multiple spots, a full water line replacement may cost less than chasing leaks one at a time.
Slab leak FAQ
Straight answers, no sales pitch.
Is a hot spot on the floor always a slab leak?
Almost always a hot-water line leak under the slab. In-floor radiant heating is the only other cause, and it's rare in LA-area homes — if you don't have radiant heat, treat a hot spot as a leak until proven otherwise.
How do you find a slab leak without tearing up the floor?
Electronic leak detection: acoustic listening equipment and thermal imaging pinpoint the leak, often within inches, before any concrete is opened. The repair hole goes where the leak is — not across your whole floor.
Will homeowners insurance cover a slab leak?
Usually the resulting water damage is covered, but the pipe repair itself often isn't. Check your policy — and document everything with photos from the day you first notice it.
How fast do I need to act on a slab leak?
Days, not months. Every day it runs is more water damage, more mold risk, and a bigger patch. A water meter test tonight costs you nothing — do that first, then call us.
Meter moving? Hot spot on the floor?
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