Water damage · Updated October 2026

Slab Leaks: Do You Need a Plumber, a Restorer, or Both?

A slab leak is a leak in a water line that runs under or through a home’s concrete foundation. Because the pipe is hidden, the damage often shows up slowly: a warm patch of floor, a damp baseboard, a water bill that keeps climbing. Fixing it usually takes two different kinds of help. A licensed plumber finds and repairs the pipe. A water damage restoration contractor dries out the slab, flooring, and walls so mold and lasting damage don’t follow.

This guide explains how to tell which you need, in what order, and how insurance may treat each part.

This guide is general information, not legal advice.

What a slab leak is

Many homes, especially in warmer parts of the country, are built on a concrete slab instead of over a basement or crawl space. Supply lines, and sometimes drain lines, run beneath or inside that slab. When one of those pipes cracks, corrodes, or breaks, water escapes into the soil and concrete under your floors.

Some slab leaks stay mostly below the surface. Others push water up into flooring, carpet pad, drywall, and cabinets. Either way, the leak itself won’t stop until the line is repaired or bypassed.

Warning signs to watch for

No single sign proves a slab leak, but these are common clues:

• A warm spot on the floor. When a hot water line leaks under the slab, the escaping water can warm the floor above it. You may notice it barefoot, or a pet may favor one spot.
• A water bill that rises for no clear reason. If your usage hasn’t changed but the bill has, a hidden leak is one possible cause. EPA WaterSense suggests looking at your winter water use as a check, noting that a family of four using more than 12,000 gallons per month could have serious leaks.
• Damp, warped, or stained flooring. Wet carpet, cupping hardwood, loose tiles, or moisture along the base of a wall can mean water is coming up from below.
• The sound of running water when every faucet, toilet, and appliance is off.
• A musty smell or mold near the floor, which can point to a leak that has been going for a while.
• A water meter that keeps moving when nothing is running (see the next section).

If you see several of these at once, call a plumber soon. A slow leak still adds up, and moisture trapped under flooring can feed mold.

How to check your water meter

A meter test is a simple way to tell whether water is leaving your plumbing when it shouldn’t. EPA WaterSense recommends that you check your water meter before and after a two-hour period when no water is being used. If the reading changes at all, you probably have a leak.

1. Turn off everything that uses water, including faucets, showers, the dishwasher, the washing machine, ice makers, and irrigation. Make sure no one uses water during the test.
2. Find your meter. It is often in a box near the street or sidewalk, or where the water line enters the house.
3. Write down the reading (or take a photo). Many meters also have a small dial or triangle that spins when even a little water is flowing.
4. Wait two hours without using any water, then read it again.
5. Compare. Any change suggests a leak somewhere between the meter and your fixtures.

A meter test tells you water is escaping, not where. A dripping toilet or an outdoor line can cause the same result, so a plumber will still need to pinpoint the source.

What the plumber does

The plumber’s job is the pipe. That usually includes:

• Leak detection. Plumbers and leak detection specialists use tools such as pressure testing, acoustic listening equipment, and thermal imaging to narrow down where the line is leaking, often without opening the floor first.
• Repair. Depending on the pipe, its age, and where the leak is, options generally include a spot repair (opening the slab or floor at the leak and fixing that section) or a reroute (abandoning the leaking line and running new pipe through walls, ceilings, or the attic instead). In some homes, repiping a larger section makes more sense.
• Testing the repair to confirm the line holds pressure.

Ask the plumber to explain the options for your home and to put the recommended repair, and the reason for it, in writing. That record also helps with an insurance claim.

What the restoration contractor does

A plumber stopping the leak doesn’t dry the house. Water that has soaked into concrete, subfloor, drywall, and cabinets can stay there long after the pipe is fixed. That’s where a water damage restoration contractor comes in.

The IICRC S500, the industry standard for professional water damage restoration, covers inspections and pre-restoration evaluations, psychrometry, and drying technology, among other topics. In practice, a restoration contractor typically:

• Extracts standing water and removes saturated carpet pad and other materials that can’t be dried in place.
• Maps moisture. Using moisture meters and sometimes thermal cameras, the crew measures how far water has traveled under flooring and up walls, and records the readings so drying can be tracked.
• Removes damaged flooring and materials as needed to reach wet areas and dry them properly.
• Dries the structure with air movers and dehumidifiers, and monitors readings until materials reach a dry goal.
• Takes steps to prevent mold. The EPA says it is important to dry water-damaged areas and items within 24–48 hours to prevent mold growth. It also notes that absorbent materials such as carpet may have to be thrown away if they become moldy.

Notably, the S500 assumes the property owner is responsible for finding and fixing the source of the water, though the owner may hire specialists for that. In other words, the standard expects restorers and plumbers to work side by side, not replace one another.

The right order of operations

Doing things out of order can waste money or trap moisture. A typical sequence:

1. Stop the water. If the leak is active and significant, close the main shutoff valve. For more on that first hour, see our burst pipe checklist.
2. Find and fix the leak. The plumber locates and repairs or reroutes the line. Drying can begin as soon as the water is off, even before the final repair.
3. Dry the structure. The restoration contractor extracts water, removes what can’t be saved, and dries the slab, subfloor, and walls, confirming with moisture readings.
4. Rebuild. Only after materials are confirmed dry should new flooring, drywall, or cabinets go in. The EPA warns that if you clean up mold but don’t fix the water problem, the mold problem will most likely come back.

How insurance may treat a slab leak

Coverage varies a great deal by policy and state, so check your own policy and talk to your insurer. In general:

• Sudden water damage is often covered; slow leaks often are not. The California Department of Insurance lists sudden and accidental water damage among perils typically covered, and water damage from seepage or leaks, along with wear and tear, among perils generally not covered. The Maryland Insurance Administration similarly says that with a slow leak, regardless of when you discover it, most homeowners policies will not cover the damage.
• The pipe itself is usually treated differently. The Maryland Insurance Administration notes that when a pipe suddenly bursts, a homeowners policy generally covers the damage caused by the water, but the repair or replacement of the pipe itself is generally not covered.
• Access (“tear-out”) may be handled separately. Some policies include language covering the cost of tearing out and replacing part of the building to reach and repair the leaking system. One insurer’s policy quoted in a federal court decision did exactly that, while excluding the leaking system itself. Wording and limits differ from policy to policy, and some policies narrow or exclude this coverage, so read yours closely.

The CDI advises that there is no substitute for reading your policy and asking your agent or insurer to clarify anything unclear, in writing.

Documenting the leak for a claim

Good records protect you no matter how coverage shakes out:

• Report the claim promptly. The CDI says you must report the damage to your insurance company to start the claim process.
• Photograph and video everything before cleanup: wet floors, stains, warm spots, the meter reading, and any opened slab or wall.
• Keep the plumber’s report describing where the leak was, what caused it if known, and what was repaired.
• Keep moisture readings and drying logs from the restoration contractor.
• Save receipts. The CDI says insurers reimburse reasonable costs to protect your property from further damage if you keep receipts, and those payments count toward the total settlement.
• Keep damaged items until the adjuster tells you it’s okay to throw them out.
• Keep a log of every call and email, with names and dates.

Know your rights

Restoration Education, a policyholder education site, explains what the industry drying standard expects from a contractor in IICRC S500: what it requires for water damage, which can help you ask good questions about moisture readings, drying goals, and what should be removed.

Getting help

A plumber fixes the pipe; a restoration contractor dries and repairs the home. If you need help with the water damage side, Restore Your Property can connect you with a licensed, certified local restoration contractor 24/7 at (855) 919-8808. Contractors in our network offer no-obligation estimates and work with all major insurance carriers.