Common slab leak signs are a water bill that rises with no change in habits, a water meter that keeps moving with every fixture off, the sound of running water in a quiet house, warm spots on the floor, and damp flooring or baseboards. A meter test is the quickest check, and a licensed plumber confirms the leak.
Key takeaways
- The strongest do-it-yourself signal is the water meter: with every fixture and appliance off, a moving dial or spinning leak indicator suggests water is escaping somewhere on your side of the meter.
- A slab leak is a leak in a supply line that runs in or under the concrete floor. Finding and fixing it is plumbing work for a licensed plumber, and Texas licenses plumbers through the State Board of Plumbing Examiners.
- Water from a slab leak can go unseen for weeks. It often shows up first as a higher bill, a warm patch of floor, or a damp edge at a baseboard rather than a puddle.
- A water bill that climbs is not proof by itself. Irrigation, a filling pool, a running toilet and seasonal use all raise it, so rule those out before assuming a leak under the slab.
- The restoration crew extracts the water, checks hidden moisture and dries slab-edge walls, flooring and cabinets. It does not reroute or repair the pipe.
What is a slab leak, and why is it a question for a new build?
A slab leak is a leak in a pressurized water line that runs under or inside a home's concrete slab foundation. Most North Texas homes are slab-on-grade, many built on post-tension slabs, so the lines sit in or beneath concrete. A newer house avoids aged pipe, but the clay under it still moves.
Most of Celina's housing arrived after 2010, a period when the town's population grew from 6,028 to 16,739 by the 2020 census. Newer homes commonly use plastic PEX supply lines, and the typical cause of a leak in that setting is different from the corroded cast-iron failures you read about in older cities. Think poor connections, a line stressed where it passes through the slab, or movement of the ground around it.
That last cause is local. Soil around Celina is blackland clay, and clay swells when wet and shrinks when dry. In North Texas, expansive clay pressing on pipes is described by plumbers as a leading cause of slab leaks, alongside corrosion and installation problems. Treat that as a general pattern, not a prediction for your lot; the point is simply that a one-year-old house is not immune.
Nothing sits below the slab to catch the water. Water from a leak under the slab surfaces through the floor, moves sideways beneath flooring and wicks into the bottom of the walls, so a small leak can spread across a wide area before anyone sees a stain.
Which warning signs point to a slab leak?
Look for an unexplained jump in your water bill, the sound of running water when everything is off, a warm area on the floor, damp or buckling flooring, wet baseboards, cracks or a musty smell, and low water pressure. Several signs together point to a leak far more than any single sign does.
No one sign is a diagnosis. A running toilet or a drip at a hose bib can mimic part of this list, which is why the table below pairs each sign with the harmless explanations to rule out first.
For water damage, the tiers matter in this way. A failed supply line or a bad fitting at the water heater is a plumbing question, which may fall under the two-year plumbing tier of the statutory minimum, depending on your warranty's wording. Window and door leaks, grading and drainage problems and finish defects land in other categories, and some warranties exclude damage from homeowner maintenance or from outside conditions.
| What you notice | Possible slab-leak meaning | Rule these out first |
|---|---|---|
| Higher water bill, same habits | Water escaping somewhere on your side of the meter | Irrigation schedule change, filling a pool, a running toilet |
| Meter moves with everything off | Strong sign of a leak on the property | An ice maker or softener refilling, a hose bib dripping |
| Sound of running water in a quiet house | Water flowing in a line under the floor | Toilet flapper, a humidifier or a water heater refilling |
| Warm spot on the floor | A hot-water line leaking beneath | Floor heating, afternoon sun through a window |
| Damp carpet or buckled flooring | Moisture rising through the slab | A spill, a pet accident, an overflowing planter |
| Wet baseboard or musty smell at a wall base | Water wicking into the wall bottom | Irrigation spray, a clogged gutter or poor grading outside |
| Low pressure or discoloured water | Pressure lost to a leak | A partly closed valve, a municipal pressure change |
How do I run a water meter test?
Turn off every fixture and appliance that uses water, including the ice maker and irrigation, then read the meter and look at the small leak indicator. If the dial or indicator is still moving, or the reading is higher after an hour with no water used, water is escaping somewhere on your side of the meter.
Many meters sit in a ground box near the street. Lift the lid carefully, and watch for insects or debris. Many meters have a small triangle or star that spins when any flow passes; if yours does not, record the numbers and check back after an hour.
To make the test fair, do not flush, run a tap or start the dishwasher or washing machine while you wait. Next, close the main shut-off valve at the house and check again. If the meter stops, the leak is inside the house or beneath it. If the meter keeps moving with the main valve closed, the leak is probably on the line between the meter and the house.
Write down what you see and take a photo of the meter. A plumber can use the readings, and so can a restoration crew's moisture log later. The meter test only tells you that a leak exists. It does not tell you where, and the water under the slab has not been located by any step you can take at the meter.
- Shut off all water use, including the ice maker and irrigation controller
- Read the meter and note the leak indicator
- Wait an hour without using water, then read again
- Close the main shut-off valve at the house and check once more
- Photograph the meter and write down the numbers
Is it a slab leak or a normal water bill?
Compare the bill with the same month last year and with your own irrigation and pool habits before assuming a leak. A true slab leak raises the bill steadily and keeps the meter moving with everything off. Seasonal use, new landscaping and a full pool rise and fall on a schedule that you can explain.
New landscaping is a classic false alarm in this market. A fresh yard in a recently built subdivision runs the irrigation system hard for the first seasons, and an irrigation line break near the foundation can wet the slab edge without being a slab leak at all. Our irrigation leak water damage page explains how those two get confused.
A toilet that runs on, a faucet that drips and a failing water-heater relief valve can each add a surprising amount to a monthly bill. Walk the house listening, check the toilets with a few drops of food colouring in the tank, and look at the water heater for dampness on the floor around the base.
If the meter test is clean, with no movement for an hour, the bill is probably about use rather than a leak. If you cannot explain a rise and the meter test fails, move to the next step: call a licensed plumber.
What should I do first if I think I have a slab leak?
Shut off the water at the main valve, keep away from standing water near outlets, and switch off power to the affected area only if the panel is safely reachable. Photograph any damage before moving anything, then call a licensed plumber to locate the leak and a restoration crew to extract and dry.
Closing the main valve stops the flow while you decide what to do. If water is pooling near outlets, appliances or a garage entrance, stay out of it, because water and electricity do not mix. Do not drill, chisel or cut into the slab yourself. Many North Texas homes sit on post-tension slabs, and cutting into one can cut a tensioned cable.
Call your insurer early. A standard homeowners policy often covers sudden and accidental water damage but may not cover a long-term leak, and coverage for the pipe repair and for the water damage can be handled differently, so read your policy or ask your agent. Check the builder's written warranty if the house is new, as the builder warranty guide explains.
The crew handles what the water reached. The plumber handles the pipe. Neither can do the other's work, and calling both the same day lets the plumber's test and the crew's moisture mapping happen in parallel.
What does slab leak restoration involve?
A crew extracts standing water, checks for hidden moisture with moisture meters and thermal tools, removes materials that cannot be dried, and sets air movers and dehumidifiers. Readings are re-checked until the slab edge, walls, cabinets and flooring reach their dry goal. Repairs after drying are quoted separately.
A leak under the slab moves in ways that surprise people. Water finds the path of least resistance, which is often along the underside of flooring or into the cavity of a wall, so the damage can be in a room away from the leak. Thermal imaging helps map the wet area, and a meter confirms what the image suggests.
The EPA's guidance is to dry water-damaged areas within 24 to 48 hours to limit mold. That is a guideline, and mold may have started in materials that were wet for weeks before the leak was found, even if they are later dried. If the leak was long-running, ask about mold, and see how Texas treats it in the mold inspection overview.
More detail on the drying process is on the slab leak water damage page and the structural drying page.
| Task | Who handles it | Notes |
|---|---|---|
| Confirm a leak with a meter test | You | Photograph the meter and note readings |
| Locate the leak and repair or reroute the line | Licensed plumber | Texas plumbers are licensed by the State Board of Plumbing Examiners |
| Extract water, find hidden moisture, dry the structure | Restoration crew | Readings are re-checked until dry |
| Report the loss and ask about coverage | You and your insurer | Coverage is decided by your insurer under your policy |
| Written warranty claim, if the home is new | You and the builder | Check your own builder's written warranty |
What does a slab leak cost, and who pays?
Plumbing costs are separate from restoration. DFW guides put slab-leak detection at about $150 to $400 and repair at roughly $2,500 to $12,000, with extreme cases above $15,000. Whether a policy or a builder warranty pays any of it depends on the cause and your documents, not on this page.
The detection range is for finding the leak. The repair range covers breaking the slab, replacing the line or rerouting it through the walls or attic, then patching. These come from local plumbing cost guides and are listed here only as context, because the plumber's quote is the one that counts. Our cost guide for Celina water damage lists the restoration side.
Insurance and warranty questions are the hard part. A policy may treat a sudden failure differently from a leak that went on for months, and a builder warranty may treat a plumbing defect differently from wear. The Texas Residential Construction Liability Act describes a written warranty of at least two years for plumbing delivery systems, but that is the statutory minimum a builder must offer to use that cut-off, not a promise any particular builder gives. Read your own contract.
If a dispute over a claim drags on, the Texas Department of Insurance takes consumer complaints about insurers.
Frequently asked questions
Can a new house really have a slab leak?
Yes. A newer home avoids corroded old pipe, but a supply line can still fail at a fitting or where the ground moves around it. North Texas clay swells and shrinks with the weather, and plumbers describe that movement as a common cause of slab leaks in the region.
Will a slab leak always make the floor wet?
No. Water can travel under flooring and into the base of walls, or sink into the soil beneath the slab, before anything shows. That is why a changed water bill, a moving meter or a warm floor patch matter more than a visible puddle.
Should I call the plumber or the restoration crew first?
Shut off the main valve, then call whichever can arrive first, and call the other the same day. The plumber finds and fixes the pipe, and the crew removes the water and dries the structure. Neither one replaces the other.
Can the crew find the leak?
A crew can map where moisture has spread using meters and thermal tools, which helps narrow the search. Locating and repairing the pipe itself is plumbing work for a licensed plumber.
Does homeowners insurance cover a slab leak?
It depends on the policy and the cause. Many policies cover sudden and accidental water damage but not long-term leaks, and the pipe repair may be treated differently from the damage. Check your policy, ask your agent, and call early.
Sources
- Texas State Board of Plumbing Examiners
- U.S. EPA – Mold Cleanup in Your Home
- Texas Department of Insurance – Consumer Help
- U.S. Census Bureau – QuickFacts, Celina city, Texas
This guide is general information for Collin County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.