Slab leak signs that need a fast call
Slab leaks hide under the floor, so the signs are indirect. A warm patch on tile or wood, the sound of water running when everything is off, a damp or mildewy smell from carpet, and a sudden bill increase all point there. Cracks in walls can also appear when water undermines soil near the slab.
We treat these as emergencies. Our dispatchers book slab leak assessments 24/7, with same-day and after-hours visits when available. Shut off the main water valve while you wait, which stops the leak from growing.
Warm or hot floor
A leaking hot water line heats the concrete above it. Floors that feel warm with the heat off are a clear sign.
Sound of running water
A hissing or trickling sound with all fixtures off often comes from a pressurized pipe leaking under the slab.
Damp flooring
Wet carpet at the edge, lifting laminate or tile grout that stays damp mean water is reaching the surface.
Unexplained bill increase
A leak of just a gallon a minute is a lot of water over a month. Check the meter with everything off.
How slab leaks are found
The plumber isolates the hot and cold lines with a pressure test to learn which line is failing. Listening equipment pinpoints the spot, and thermal imaging confirms a hot water leak. Marking the floor lets the repair open the smallest possible area.
Finding the leak is the same method used for hidden leaks in walls, covered in more detail on leak detection.
OptionsRepair options for a slab leak
| Option | How it works | Trade-off |
|---|---|---|
| Spot repair through the slab | Cut the concrete over the leak, repair the pipe, patch the floor | Best for a single leak in an otherwise sound system. Flooring above is disturbed. |
| Reroute through walls or attic | Abandon the failing line and run a new line overhead | Avoids concrete, but opens walls and ceilings. |
| Repipe | Replace the failing supply lines across the home | Best for repeated leaks. See repiping. |
Why slab leaks start
Pipes that run under concrete face soil movement, corrosion at the outside of the pipe, abrasion where the pipe rubs against the slab, and water chemistry. A copper line can pit and fail from the outside. Older fittings fail at joints. Pressure that is too high stresses the whole system, so a plumber may check pressure at the same visit.
Sanger's municipal water averaged 145.5 ppm hardness in the city's 2024 water quality report, with results as high as 330 ppm. Hard water leaves scale inside pipes, and old scaled fittings are among the first to seep. Testing your own water is a good way to know what the lines see.
Slab leaks and your insurance
Many policies cover the water damage from a sudden slab leak, and some pay for the tear-out needed to reach the pipe, but few pay to repair the pipe itself. Policies differ, so call your agent before work begins and ask what documentation they need. A written leak report with photos helps the claim.
What affects the price of slab leak repair
Slab leak work is priced by method and by what has to be restored afterward. We give a clear price before work starts, after the leak is located.
Want your real number? Call (855) 575-2890 and describe the signs.
Floor warm or bill climbing?
Call the 24/7 line for emergency slab leak repair in Sanger.
Slab leaks in Sanger homes
The city's housing element reports that 53 percent of Sanger homes are more than 30 years old and 29 percent more than 50. Homes of that age may have original copper supply lines under the slab. A single repair may be right for a young system, and a home with decades of use may justify a larger plan.
If you are in nearby Selma or Reedley, the same 24/7 line covers you. See Selma and Reedley.
Safety stepsWhat to do before the plumber arrives
- Shut off the main valve if you hear water or feel a warm floor.
- Turn the water heater to off if the leak is on the hot line.
- Keep electronics off wet floors.
- Do not drill or cut into the slab yourself.
Rules for slab repairs
The California Plumbing Code, which is based on the Uniform Plumbing Code (UPC), sets the rules for pipe, fixture and water heater work in the state. Breaking a slab or rerouting lines overhead is done by a licensed plumber, and the work may need a permit. Ask your building department what applies. Plumbing work is done under a C-36 license from the Contractors State License Board, and you can look up any license on the CSLB website.
FAQSlab leak questions
Yes. The line answers 24/7, and same-day visits are booked when available. Shutting off the main valve stops the leak from growing.
Usually not. The plumber may ask you to stay out of the affected room while the floor is open.
Spot repairs can finish in a day. Rerouting and repiping take longer. The plumber gives an estimate after locating the leak.
Waiting means more water, more damage and a higher bill. Shut off the main valve if you must wait.
Plumbers open and repair the pipe and patch the slab. Finish flooring is usually a separate trade.