A slab leak is a leak in a water line that runs in or beneath a concrete slab foundation. It is hidden, it can run for weeks, and it can raise your water and gas bills before you ever see damage. If you suspect one right now, call the 24/7 line and follow the shutoff steps in the urgent section below.
Hanahan sits at about 16 feet above sea level, and several neighborhoods have tidal water behind them. That is a good reason not to assume that every damp floor is a failing pipe, because wet ground can send moisture up through a slab or into a crawlspace on its own. The simple check is the water meter: if it moves while every tap is off, a pipe is leaking, and if it holds still, the moisture has another source.
A warm spot, a sound or a bill that jumped: how a slab leak shows up
The first sign is often not water. A spot on the tile or carpet that stays warm when the heater has been off points to a hot water line leaking under it. You may also hear a faint rushing sound from the floor when everything in the house is off, or notice the water heater running more than usual because it keeps heating water that leaks away.
The next signs are a higher water bill, lower pressure at one end of the house, a musty smell, baseboards that swell or pull from the wall, and damp patches along the foundation edge. Any one of these can have another cause, but two or three together make a pipe leak far more likely.
Suspected slab leak: what to do right now
Water under a slab cannot drain, so it spreads sideways and upward. Slow it down first.
Shut off the main
Closing the main shutoff stops the leak from feeding while you arrange the repair.
Turn off the water heater
Switch off the breaker for an electric heater, or set a gas heater to pilot. A heater with no water refilling it can overheat or damage its elements.
Stay off wet floors
Water and electricity do not mix. If baseboards or outlets are wet, shut off the breaker for that room only if you can reach the panel while standing on dry ground, otherwise stay out and call 911 or the electric utility.
Open a faucet to drain pressure
With the main closed, open the lowest faucet to let the standing pressure out. This reduces leaking from the damaged line.
Call the 24/7 line
Give dispatch your meter reading, the warm spot's location and your foundation type. Same-day appointments are offered when available, and after-hours calls are dispatched.
Confirming the leak and your foundation type
Some Hanahan homes sit on a slab and others on a raised foundation with a crawlspace. The first job is to know which you have, because the repair differs completely.
- 1
Identify the foundation
Look for vents or an access door at the base of the house, which signal a crawlspace. A flush concrete edge at ground level usually means a slab. Your home inspection report or deed paperwork will also say.
- 2
Run a meter test
With everything off, note the meter reading, wait 30 to 60 minutes and check again. Movement means water is escaping. See our leak detection page for the full test.
- 3
Isolate hot from cold
A warm floor spot suggests a hot line. Turning off the water heater's supply valve and watching the meter helps tell hot from cold.
- 4
Pressure test the lines
A plumber isolates sections of piping, gauges pressure and finds the failing run.
- 5
Pinpoint with listening and thermal tools
Electronic listening gear or a specialist method named before booking marks the spot on the floor before anyone cuts concrete.
Water or sewage problem right now?Call the 24/7 line. A licensed plumber, a clear price before work starts.
Call (855) 575-2890Slab leak repair options and their trade-offs
There are three ways to fix a leak under a slab. The right one depends on how many lines are failing, the pipe material and what the floor is made of.
| Option | How it works | Good when | Trade-off |
|---|---|---|---|
| Spot repair through the slab | Cut a small opening in the concrete over the leak, replace the damaged section and patch the slab | One leak, accessible location, pipe otherwise in decent shape | Floor covering above is removed and may not match afterward. Other weak spots can fail later |
| Reroute overhead | Abandon the leaking line and run new pipe through the attic or walls to the fixtures | The under-slab line is failing in several places or hard to reach | Pipe in walls and ceilings, with drywall repair. Costs more than a single spot repair but avoids cutting the slab |
| Repipe | Replace most or all supply lines in the house with new pipe | Pipe is old, brittle or has leaked more than once, or the system is a type known to fail | Highest cost and most disruption, but usually ends repeat leaks. See whole-house repiping |
None of these is the cheap fix in every case. A second leak a year later after a spot repair can make a reroute or repipe the better value.
How a leak raises your water and gas bills
A leak on a hot water line costs twice, since you pay for the water and then for the energy to heat it. That is why a slab leak can show up first as a high electric or gas bill and only later as a high water bill. If the heater cycles on when no one has used hot water, a hot line may be losing water under the floor.
For the water side of the bill, a meter test tells you whether water is moving. If the meter holds still but the bill looks wrong, call CWS at (843) 727-6800 to check the account.
When moisture under the floor is not a pipe at all
Damp flooring, a musty smell and condensation on slab edges can come from groundwater, poor drainage around the foundation, a roof or gutter that dumps water against the wall, or a clogged air conditioner drain. Neighborhoods near tidal water can see ground stay wet longer after a big rain, and that moisture can come up through cracks in a slab.
A plumber can tell the difference with a meter test and a pressure test. If the pipes hold, the fix may be grading, gutters or drainage, and cutting into the slab would be an expensive mistake.
Documenting a slab leak for your insurance claim
Good records can change how a claim goes. Collect them before cleanup begins.
- Photos and video of the warm spot, damp baseboards, stained flooring and the meter dial with a timestamp
- The meter reading before and after your home test
- A written log: when you first noticed the sign, what you did and when you shut off the water
- Copies of your water bills for the last several months, to show the change
- The plumber's written findings, including where the leak was found and what caused it
- Receipts for emergency shutoff supplies, fans, drying or temporary lodging
- Your carrier's claim number, adjuster name and the date they inspect
Ask your carrier whether your policy covers the cost of reaching the pipe, not only the repair of the pipe.
Spot repair or repipe: choosing for your house
A single leak in a newer system can be a clean spot repair. Repeated leaks, old metal pipe that is thinning, or a house that has had several repairs usually point toward rerouting or repiping. Homes built during the polybutylene era, roughly 1978 to 1995, deserve extra attention, since that gray plastic supply pipe is known for failing at fittings.
We will tell you plainly what the pipe looks like, which option fits and what each would involve, including the floor covering. Ask us about the floor first, since tile, hardwood and carpet change both the repair and the finish work. Some jobs may need a permit, so ask the City of Hanahan Building and Codes department.
Our Goose Creek and North Charleston neighbors often have the same question after a repair, and the answer comes down to how much of the system is original.
What affects the price of a slab leak repair
A clear price should come before work starts, and it should say what is and is not included.
- Locating the leak
- Detection takes time and equipment, and a leak that is hard to pinpoint costs more to find.
- The repair method
- A spot repair, a reroute and a repipe differ by a large margin, and the difference grows with the size of the house.
- Floor covering
- Cutting through tile, hardwood or carpet and replacing it adds labor and materials, and it may not be covered by the plumbing price.
- Pipe material and condition
- Copper, PEX and older pipe types cost differently to work with, and weak pipe may call for more replacement.
- Timing
- Emergency and after-hours calls cost more than scheduled visits.
Sudden, accidental water damage is often covered, while damage from a long-running leak and normal pipe wear often is not. Some policies pay to reach the pipe even when they do not pay to replace it. Ask your carrier before work begins.
Call with your meter reading and floor type, and we can give you a clear price before any work starts.
Frequently asked questions
Do you handle slab leak emergencies at night or on weekends in Hanahan?
Yes. Our 24/7 dispatch covers nights and weekends, and a licensed plumber can come out when water is spreading under the floor. For a slow leak, same-day appointments are offered when available.
How can I tell if my house is on a slab or a crawlspace?
Look at the base of the house. Foundation vents or a small access door suggest a crawlspace, while a flat concrete edge flush with the ground suggests a slab. Some houses have both, such as an addition built on a different foundation.
Is a warm spot on my floor always a slab leak?
No. Sun through a window, a heating duct, a hot water line running along the floor and in-floor heat can all warm a spot. A warm spot that follows a meter that moves with everything off is the combination that points to a leak.
Can a slab leak be fixed without breaking the concrete?
Sometimes. Rerouting the supply through the attic or walls avoids cutting the slab. A leak in a drain line sometimes allows lining without much digging. Which route fits depends on the layout of your home.
How long can I leave a slab leak before it does damage?
There is no safe number. Water under a slab can undermine soil, ruin flooring and feed mold, and the bill keeps rising. Close the main if you can and call.
Will my insurance pay for a slab leak?
That depends on the policy and on whether the leak was sudden. Document everything and call your carrier early. Ask whether they cover access to the pipe as well as the repair.