The short answer
Slab leak detection is priced as a diagnostic visit, separate from the repair. The plumber uses tests and listening equipment to find where a pressurized line is leaking under the concrete. The price depends on how many tests are needed and how hard the pipes are to reach.
A reliable detection shows the leak location within a small area, so repair work opens as little concrete as possible. For a real number, call (916) 312-0578. Our slab leak repair page covers what comes after.
Signs that point to a slab leak
Slab leaks are hidden, so the symptoms are indirect. Watch for these.
A water bill that jumps
The meter keeps turning even when every fixture is off.
A warm spot on the floor
A leaking hot line can heat the slab above it.
The sound of running water
You hear it with the house quiet.
Damp carpet or lifting flooring
Moisture rises through the slab and shows at the surface.
Low water pressure
A leak pulls pressure away from the fixtures.
Detection methods and what each shows
A plumber chooses tests that narrow the search step by step.
| Method | What it does | What it tells you |
|---|---|---|
| Meter test | Checks the meter with everything off | Whether water is leaking at all. |
| Pressure test | Isolates lines and watches the gauge | Which line is losing pressure. |
| Electronic listening | Picks up the sound of escaping water | The approximate point on the slab. |
| Thermal imaging | Reads temperature differences | Where a hot water leak is warming the floor. |
| Camera inspection | Looks inside drain lines | Whether the problem is a drain, not a supply line. |
What Dixon rules say about under-slab pipes
Source type: City of Dixon permit handouts and water quality report.The City of Dixon's water line handout requires copper under a slab to have no joints, and lists Type L copper below buildings. Pipe with no joints leaks only at a defect or where corrosion thins the wall. That helps the plumber narrow the search to a long run rather than a connection.
The same handout states that supply pressure should be tested at working pressure for 15 minutes after a repair. The City of Dixon's 2024 report lists system pressure between 52 and 62 pounds per square inch, which is steady pressure that keeps a small leak flowing day and night.
Pipe material is a code item. Section 604.1 of the California Plumbing Code, which is based on the Uniform Plumbing Code (UPC) is the supply pipe rule the City of Dixon's water line handout cites.
Think you have a slab leak?
Call and describe the symptoms. A same-day appointment is offered when available.
What changes the detection price
The price depends on the work needed to find the leak, not on the size of the house alone.
Some insurers cover the cost of finding a covered leak even when they exclude the repair. Ask your agent before the visit and keep every document.
What a good detection report includes
A useful report names the line that is leaking, marks the approximate spot on the floor and notes how the plumber reached that conclusion. Photos of the marks and a short written summary help when you talk to an insurer or compare repair quotes.
If the plumber cannot find the leak with the first method, a good report says what was tried and what comes next. Honest detection sometimes ends with a recommendation to reroute a line rather than to dig.
What you can do before the visit
A few simple steps make the detection faster and the results clearer.
- Do the meter test and write down the readings.
- Note which rooms feel warm or damp.
- Turn off sprinklers and ice makers so they do not confuse the test.
- Move furniture away from suspect areas.
- Gather recent bills to show the change in usage.
Slab leak or something else
A wet floor does not always mean a slab leak. A leaking shower pan, a failed toilet seal or a drain line problem can all moisten a floor. A plumber rules these out with simple tests before moving to listening equipment.
A drain leak under a slab is a different repair from a supply leak. The sewer camera inspection page explains how cameras check the drain side.
How long detection takes
Plan on a few hours for most homes. The meter and pressure tests are quick. Listening takes patience, because the plumber needs quiet to hear small sounds through concrete. Turn off televisions, fans and music during the visit.
A larger house or an old layout with several lines under the slab takes longer. The plumber should tell you the plan when they arrive and give you an update if something changes.
Questions to ask the plumber
Ask which tests will be used and in what order. Ask whether the price includes a written report and a marked floor. Ask what happens if the leak cannot be found on the first visit and whether a return trip is priced separately.
Those three answers tell you most of what you need to compare detection quotes.
After detection: your options
Once the leak is found, you can repair it under the slab, reroute the line through the attic or walls, or repipe the house. The right choice depends on the age of the pipes and how many leaks there have been. A plumber explains the choices and the price of each before you decide.
A leak outside the house is a different case. Our water line repair page covers lines between the meter and the building, and leak detection covers the full process. We serve Dixon, Vacaville and Davis.
Slab leak detection questions
Yes. Pressure tests, listening equipment and thermal imaging locate most leaks without opening the slab.
Often part of a day, depending on the layout. The plumber gives you a window when you book.
Some policies pay for the cost of locating a covered leak. Policies differ, so ask your agent first.
A meter test and a separate test on the line to the house show which section is leaking.
The City of Dixon's water line handout calls for copper under a slab to have no joints.