What a slab leak is and why it hides
Many homes sit on a concrete slab, and the water supply lines or drain pipes run in or beneath it. A slab leak is a break or pinhole in one of those pipes. Because the pipe is buried, the first signs are indirect, and they can go unnoticed for weeks.
Hot lines under a slab are common culprits, but cold lines and drains can leak too. The signs below overlap with other leaks, so treat them as a reason to test, not as a final answer.
Signs a slab leak may be present
One of these alone is a clue. Two or three together point more strongly to a leak under the floor.
Water meter keeps moving
The meter runs with every fixture and appliance off. This is the clearest test.
Warm or hot spot on the floor
A section of tile or flooring feels warm with no heater below it, often from a leaking hot water line.
Sound of running water
A faint hiss or trickle is audible when the house is quiet and nothing is running.
Unexplained rise in the bill
Water use climbs with no change in habits.
Low water pressure
Pressure drops at several fixtures because water is escaping before it arrives.
Damp carpet, cracked tile or lifting floor
Moisture pushes up through the slab and damages flooring from underneath.
Warm floor or a moving meter?
Call the 24/7 line. We locate the leak with listening gear and thermal imaging before anyone breaks concrete.
A musty smell, mold and damp baseboards
Water under a slab can wick up into walls and flooring. A musty smell in one room, a stain at the bottom of a wall or paint that bubbles near the floor can all mean moisture is coming from below. In a warm, humid climate mold can start quickly once a surface stays damp.
Check the same spot after a dry spell. If a stain returns without rain or a nearby fixture explaining it, the source may be under the floor. Do not paint over it, because the leak will keep going while the paint hides the evidence.
How to check before you call
These steps confirm a leak without any tools beyond your meter and your hand.
- 1
Shut everything off
Turn off the ice maker, the washing machine, the irrigation timer and every tap.
- 2
Read the meter
Write down the reading or note the low-flow indicator, then wait fifteen to twenty minutes.
- 3
Close the main valve
If the meter keeps moving, the leak is between the meter and the house. If it stops, the leak is inside.
- 4
Feel the floors
Walk barefoot in the room above the suspected line and note any warm spot, then mark it with painter tape.
- 5
Listen at night
Put an ear near the floor, a wall and the water heater when the house is quiet.
Slab leak or something else
Other problems copy a slab leak. This comparison helps rule them out.
Points toward a slab leak
- Meter moves with all fixtures off.
- Warm floor in one area.
- Damp flooring with no plumbing above it.
- Sound of water under the floor.
Points toward something else
- Meter stops when the main valve closes.
- Water only appears near a toilet, tub or sink.
- Stain on a ceiling directly under a bathroom.
- Leak seen under a cabinet or behind an appliance.
Who to call about the line before the house
In Coconut Creek, water service north of Coconut Creek Parkway comes from the City of Coconut Creek utility, and service south of the Parkway comes from the City of Margate utility. If your meter test shows the leak is between the meter and the street, or you see water at the meter box, the utility should hear about it.
Margate lists a line for water line breaks, low pressure and sewer stoppages at 954-972-0828. Inside the meter on your side, the pipes are yours, so a slab leak is a plumber job and not a utility repair. Knowing which side of the meter the leak sits on saves a phone call to the wrong place.
Source: the City of Coconut Creek water services page and the City of Margate utility page (municipal utility pages).
What happens when we confirm a slab leak
Location comes first. We use listening equipment and thermal imaging to narrow the leak to a small area, so repairs open as little floor as possible. See our leak detection page for how the tools work.
Repair options include a spot repair through the slab, rerouting the line through the walls or attic, or repiping if the pipe is failing in several places. Our slab leak repair team walks you through each option and the trade-offs, and our repiping crew handles the larger jobs.
If you suspect a slab leak right now
Do these things while you wait for a plumber.
- Shut off the main valve if the meter is spinning fast or water is visible.
- Move rugs, furniture and electronics away from damp floors.
- Photograph stains, warm spots and meter readings.
- Do not drill or cut into the slab yourself.
- Note when the signs started, which helps with insurance questions.
Honest limits
The signs can suggest a slab leak, but only location work confirms it. We do not cut into a slab on a guess, and we do not recommend a repipe until the leak has been found and the rest of the line has been assessed.
If the meter test is clean, the cause may be elsewhere, such as a toilet, an irrigation line or a stain from the roof. Neighbors in Margate and Coral Springs call us for the same checks.
Slab leak signs: common questions
Often a higher water bill or a meter that moves with everything off. Warm floor spots and a faint sound of running water follow in many cases.
Yes. Hot lines get more attention because they create warm spots, but cold lines and drains also leak under slabs.
It can be. Water under a home damages flooring and can undermine the soil. If you see water or the meter is running fast, shut off the main and call.
Coverage depends on the policy and the cause. Some policies cover resulting damage but not the pipe itself. Read your policy or ask your insurer before work starts.
Sometimes. Rerouting the line through a wall or attic avoids the slab. The right choice depends on where the leak sits and the condition of the rest of the pipe.
The utility that serves your address, either the City of Coconut Creek or the City of Margate. Pipes on the house side of the meter are your responsibility.