Short answer: A slab leak is a leak in a water or drain pipe that runs under or inside a home's concrete slab floor. Common causes are worn copper pipe, pipes rubbing against concrete, poor installation and high water pressure. Warning signs include warm spots on the floor, running-water sounds, damp baseboards and a meter that moves when no water is in use.
Many Florida homes, including most in Sarasota, are built on a concrete slab poured right on the ground. The water lines and drains run under or through that slab. When one of those pipes leaks, you can't see it. You only see what the water does. If you think you have one, SRQ Leak Pros can connect you with a local pro for slab leak repair in Sarasota.
What is a slab leak?
A slab leak is any leak in plumbing that sits below or within a concrete slab foundation. There are two main kinds:
- Supply line leaks. A pressurized hot or cold water pipe leaks. These run all the time and raise your bill.
- Drain line leaks. A drain or sewer pipe under the slab cracks. These leak only when water goes down the drain, and can cause odors or soggy soil.
Most slab leaks people notice are on the supply side, because pressure keeps them running.
What causes slab leaks?
| Cause | How it happens |
|---|---|
| Pipe wear | Water flow, minerals and sand thin copper over time |
| Abrasion | Pipes expand and rub against concrete, gravel or rebar |
| Poor installation | Kinked pipe, bad joints or missing protective sleeves |
| High water pressure | Extra stress on pipe walls and joints |
| Soil movement | Settling or shifting soil under the slab |
| Water chemistry | Some water conditions speed up copper corrosion |
Hot water lines also expand and contract each time they heat up and cool down, which adds stress where they touch concrete.
Warm spot or running-water sound? Call to reach a local slab leak pro.
Call (941) 541-0938Warning signs of a slab leak
- A warm or hot spot on tile or carpet
- The sound of water running when every tap is off
- Damp, stained or swollen baseboards
- Cracks in tile or new cracks in the slab
- Mildew smell or mold near the floor
- The water heater runs more than usual
- Low water pressure
- The water meter moves with all fixtures off
- A higher water bill with no change in use
Any one of these can have other causes. A meter test is the quickest way to know whether water is leaving the system. The EPA's version is simple: read the meter, use no water for two hours, then read it again.
How is a slab leak found?
A pro works from broad tests to precise ones:
- Meter and isolation tests confirm the leak and narrow it to hot or cold.
- Pressure tests show which section is losing water.
- Acoustic listening through the concrete detects the sound of the leak.
- Infrared cameras show warm areas from hot water leaks.
- Tracer gas can find quiet leaks in cold lines.
Wikipedia lists acoustic, infrared, hydrostatic and tracer-gas methods among the standard ways to detect pipeline leaks.
How is a slab leak fixed?
There are several options, and the best one depends on the leak and the age of your plumbing.
| Fix | What it means |
|---|---|
| Direct repair | Open a small hole in the slab and fix the pipe |
| Tunneling | Dig under the slab from outside |
| Reroute | Run a new line through walls or the attic and abandon the old one |
| Repipe | Replace the home's supply lines |
| Epoxy lining | Seal the inside of the pipe, for suitable pipes |
If you have had more than one slab leak, ask about repiping.
How much does a slab leak cost?
Angi's national data puts the average slab leak repair at about $2,300, including detection. Read the slab leak repair cost guide for the factors behind that number.
Are slab leaks dangerous?
Most slab leaks aren't an immediate danger, but they shouldn't wait. Over time a slab leak can soak flooring and drywall, encourage mold, wash out soil under the slab and waste a lot of water. If water is coming up through the floor or pressure has dropped sharply, shut off the main valve and get help.
How to prevent slab leaks
- Have water pressure checked, and install a pressure reducing valve if it's high.
- Watch for warm spots and damp baseboards, and act early.
- Read your water meter monthly.
- Consider a whole-house leak sensor or automatic shut-off.
- After one leak, ask the pro about the condition of the rest of the pipe.
Local note: many older slab homes in Bradenton and Venice have copper under the floor that is now decades old. Ground-floor condos on Siesta Key can face slab leaks that affect common areas.
Related reading: if you're filing a claim, see does insurance cover slab leaks. To learn why copper fails, read about pinhole leaks in copper pipes. Before you call a contract company, learn what home warranty plans cover for slab leaks.
When should you call a slab leak professional?
Call a pro when:
- The meter moves with every fixture off and the house is the source
- You feel a warm spot or hear water under the floor
- Flooring or baseboards are damp
- Your water heater runs much more than usual
Think you have a slab leak? Call (941) 541-0938 to reach a local pro for detection.
Call (941) 541-0938Frequently asked questions
Can a slab leak fix itself?
No. A slab leak will keep leaking and usually gets worse. It needs to be found and repaired.
How long can a slab leak go unnoticed?
Small slab leaks can run for months, especially in homes that sit empty for part of the year.
Are slab leaks common in Florida?
Slab foundations are very common in Florida, so slab leaks are a frequent repair here.
Can I stay in my house with a slab leak?
Usually, yes, while you arrange a repair. If water is coming through the floor or pressure has dropped sharply, shut off the main and call for help.
Sources
Related guides
Costs & InsuranceSlab Leak Repair Cost: What Sarasota Homeowners Can Expect
Angi's national averages, how repair methods change the price, and the costs people miss.
Pipes & RepairsPinhole Leaks in Copper Pipes: Causes, Signs and Fixes
Why copper develops tiny holes, how to spot them, and when one repair turns into a repipe.