Picture a house with a concrete floor and a water supply pipe cast into or buried beneath it. When that pipe pinholes, nothing shows for a while. The company you pick for the repair earns its fee by locating the break first, offering you more than one way to fix it, and putting the choice in writing. Our hub on plumbers for leaks in Torrance sets out the wider leak picture; this page is about choosing who does the slab work.
How would I know the water is escaping beneath the floor?
Typical clues are one stretch of floor that stays oddly warm, a faint hiss or trickle at night, a meter dial that turns while every tap is shut, an unexplained jump in the water bill, damp carpet near an exterior wall, and cracking in baseboards. Several together suggest the slab. Only detection equipment settles it.
Many South Bay houses stand on concrete slabs with supply lines laid in or under them. Wikipedia's overview of slab foundations notes that copper pipe in a slab can corrode and leak over time, which is how pinholes appear. Hot lines tend to go first.
Cheap checks before you call anyone:
- Meter. EPA's WaterSense program offers a simple home test. Jot down the meter number at bedtime-quiet, with every fixture idle, and compare it two hours on; a different figure means water is leaking out.
- Toilets. A few drops of food dye in each toilet tank will expose a leaking flapper: dye reaching the bowl in ten minutes clears the slab of blame for that fixture.
- Floor. Walk barefoot over tile and feel for one oddly warm stretch.
If the dial moves and the toilets are clean, ask for leak detection before anybody breaks concrete.
What should a competent company do before it quotes a price?
It should pinpoint the break. That usually means pressure-testing the lines one by one to see which is losing water, then listening with acoustic gear along the floor, and sometimes using thermal imaging or tracer gas. A company that offers to start cutting without that step is guessing at your expense.
A sound visit leaves you with:
- proof of which line is failing (hot, cold, or a branch);
- a chalk mark or photo showing where on the floor the break sits;
- a note of what lies above it, such as tile, cabinets or a wall;
- a written scope with at least two repair options and prices.
Pricing for the detection step is covered on leak detection cost, and the repair side on slab leak repair cost.
Which repair methods exist, and which should I pick?
Three. Spot repair opens the slab over the break and replaces a short section. Rerouting means retiring the bad line and serving the fixtures from fresh pipe in the attic or wall cavities. Repiping replaces the whole supply system. A single failure in healthy pipe favors a spot repair; repeat failures or aging pipe favor rerouting or repiping.
Weighing them:
- Spot repair: quickest when one clean break is the only problem. Concrete is cut and patched, so flooring above it is disturbed.
- Reroute: leaves the floor alone and trades it for openings in walls or ceilings. Useful when the pipe path is long or the floor finish is costly.
- Repipe: sensible when leaks keep returning. Choosing between a repair and a repipe weighs the two, and PEX versus copper covers material choice.
Ask what the company would pick for your house, its reasons, and how the bill changes should plan A not work. Work that opens a slab or alters supply pipe generally needs a plumbing permit; Torrance's Building and Safety division lists pipes among permitted work and accepts applications online.
How do I vet a company before it touches my floor?
Type the contractor's number into the Contractors State License Board lookup. Plumbing is classification C-36. Confirm the status is active and the name matches the quote, and read any complaint history. Then demand a written quote naming the leak location, the method, the permit, and who restores the floor. A company reluctant to write it down is not ready.
California also has consumer rules for home improvement contracts, including a written contract, a limit on deposits and a right to cancel in many cases. The board's consumer pages carry the current terms, so read those before signing instead of trusting anyone's paraphrase, including ours.
Red flags particular to slab jobs:
- a figure given by phone before anyone has detected anything;
- eagerness to break concrete before the leak is confirmed;
- a big cash deposit requested at the start;
- silence about permits;
- no plan for the flooring, cabinets or drywall the work disturbs.
Anyone you hire directly should pass these tests too. When we arrange a visit, the quote arrives on paper first.
What about my flooring and the water that already escaped?
Spot repair means cutting through the flooring above the break. Rerouting spares the floor but opens walls or ceilings. Water that has already spread can soak underlay, drywall and cabinet bases, and Wikipedia's water damage overview says mold can begin within 24 to 48 hours in damp materials, so drying cannot wait.
Find out who restores the surface, since drying and finish work are often different trades. Take pictures of the damage while it is untouched, and hold on to all paperwork. For the insurance angle, our page on whether homeowners insurance covers broken pipes under a foundation lists what to ask, and policies vary, so ask your insurer before the first cut.
Can I do anything while I wait for the company?
Closing the main valve is the real stop, since the leak itself cannot be reached. Opening a faucet afterward eases pressure. A leak on the hot side may be isolated by closing the valves at the water heater. Never cut the floor yourself; other pipes, gas lines and wiring may share the slab.
If water is rising through the floor, the floor is hot, or you smell gas, leave and ask for help. A gas odor changes everything: walk outside and dial 1-800-427-2200 for SoCalGas. When water is gushing now, the first moves are on our burst pipe emergency page.
Common questions
How long is the job from start to finish?
Detection normally takes a morning or afternoon. A short section replaced through the slab might take a day, and then comes cure time for the concrete and the new floor surface. Rerouting and repiping run longer. Ask for a schedule covering plumbing, the permit inspection and surface restoration.
Which points should I settle before signing?
Settle the contractor license number, how the leak will be pinpointed, the repair options with a price for each, whether the permit is included, who restores the floor, and how long the work is covered. Put each answer on paper before any cutting is approved.
Do I need to be around?
Ideally. You know what you heard and saw, you can show where the meter and main sit, and you should walk the finished work with the plumber. The supply will be off for some hours. Mention pets, access and alarm codes, and move furniture off the work area.
Does it count as an emergency?
It is urgent more often than it is an emergency. Shut the main if flow is heavy, because a slab leak can run for ages without showing. Water surfacing through the floor, or a bill climbing fast, calls for a prompt visit. Request a written quote to begin.
Must the whole house be repiped?
No, not by default. One failure in otherwise healthy pipe can be repaired in place. Repiping becomes worth weighing when leaks recur, the pipe is old or corroded, or the repair bills start nearing what a new system would cost. A pressure test of the remaining lines helps the decision.
This guide is one of many on the plumber guide for Torrance.
Sources used
Last updated