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How can I tell if I have a slab leak?
A straight answer first, then what you can safely check yourself and when to get a pro. Free estimates from a vetted MB pro near you.
You may have a slab leak if your water meter keeps moving with every fixture off, parts of the floor feel warm, you hear running water when the house is quiet, or your water bill jumps for no reason. A simple meter test and a walk through the house will tell you whether water is escaping. Only a pro with leak-detection equipment can confirm that the leak is under the slab.
A moving meter means water is leaking somewhere, not necessarily under the floor. A running toilet, an irrigation line or an outdoor spigot can look the same, so rule those out first.
Why slab leaks happen
In many Florida homes built on a concrete slab, some water lines run under or inside the concrete. Over the years those pipes can corrode, rub against gravel or concrete, or be stressed when the slab shifts slightly. Older supply pipe such as polybutylene can also fail without warning.
The leak is hidden, so it shows up through side effects: a floor that feels warm over a hot water line, damp carpet or lifted flooring, a musty smell, moisture along baseboards, or a water heater that seems to run constantly. In a humid climate, hidden moisture can also feed mold, so it is worth acting early.
What you can check yourself
Run a meter test
Turn off every faucet, the dishwasher and the washing machine, then look at your water meter. If the leak indicator is spinning or the dial is moving, water is going somewhere.
Rule out the easy culprits
Check for a toilet that keeps refilling, a dripping faucet or a wet spot in the yard near an irrigation line. These are common causes of a moving meter and have nothing to do with the slab.
Feel and look at the floors
Walk barefoot or use your hand to find warm spots on tile or concrete, and look for damp carpet, cracked grout, buckled flooring or moisture at the base of walls.
Listen in a quiet house
With everything off, listen near floors and walls for a faint hiss or the sound of running water.
Compare your water bills
Look at recent bills next to the same months last year. A rise you cannot explain by guests, watering or a pool fill is a useful clue.
When to stop and call a pro
Call a pro if the meter test shows a leak and the easy causes are ruled out, if a floor is warm or wet, or if you see water coming up through flooring. If water is spreading, shut off the main valve to the house. Do not touch outlets or appliances near standing water, and never cut or break into the slab yourself.
Florida requires plumbing work to be done by a licensed plumbing contractor under chapter 489, Florida Statutes. A building or roofing license does not cover plumbing, and you can check a license number on the Florida DBPR website. Re-piping a home typically needs a plumbing permit from the city or county, pulled by the plumbing contractor. MB matches homeowners with a pro for plumbing in Miami-Dade, Broward and Palm Beach counties only, and we match you with a vetted pro near you.
Your MB pro handles the permit when the job needs one. You can look up a contractor's license at Florida DBPR.
What your MB pro will do
- Pinpoint the leakYour MB pro will use leak-detection methods, such as listening equipment and pressure testing of isolated lines, to find where the water is escaping before anything is opened up.
- Explain your optionsDepending on what is found, the fix may be a spot repair through the slab or re-routing or re-piping the affected line. Ask the pro to compare options and explain why they recommend one.
- Handle the permitIf the work includes re-piping, the contractor is responsible for pulling the plumbing permit. Ask whether one is needed and who is handling it.
- Check the rest of the systemA leak in one section can mean the same pipe is aging elsewhere. Ask the pro to look at the pipe material and whether other sections are at risk.
How it works
Step 1
Tell us what you need
Call or send the short form with your city and the job. Estimates are free.
Step 2
We match you with a vetted pro near you
We pick a vetted pro from our network who works in your part of Florida and book the visit.
Step 3
Your pro gives a free estimate and does the work
Your MB pro looks at the job and gives you a free estimate. You decide whether to go ahead — and we stay your point of contact.
Related questions
- Can a slab leak fix itself or wait?
- No, a leaking pipe does not repair itself. Water under the slab can wear away soil, damage flooring and feed mold, so the problem tends to grow the longer it is left. Shutting off the main valve buys time until a pro arrives.
- What affects the cost of a slab leak repair?
- The main factors are how deep and how accessible the pipe is, how many lines are affected, the pipe material, whether a permit is needed, and the flooring that has to be opened up and restored. Your MB pro gives a free estimate once the leak is located.
- Will homeowners insurance cover a slab leak?
- It depends on your policy and what caused the leak, so ask your insurer before work begins. A written report from the plumbing contractor describing what was found can help with that conversation.
- Should I turn the water off if I suspect a slab leak?
- Yes, closing the main shutoff is a safe way to stop water loss while you wait for a pro. You will not have water in the house until it is reopened, so plan around that.
Request a free plumbing estimate
Tell us what's going on. We'll match you with a vetted pro near you.
- 1Tell us what you need.
- 2We match you with a vetted pro near you.
- 3Your pro gives a free estimate and does the work.
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