When a hidden leak becomes urgent
A leak behind a wall or under a floor damages drywall, framing and flooring the longer it runs. If you hear water with every tap off, see a wet spot spreading or smell mildew, call the 24/7 line. We book same-day visits when a technician is free, and the dispatcher can talk you through the first steps.
Shut off the main water valve if the leak is active and visible. Then switch off power to any wet area at the panel, only if you can reach the panel without stepping in water.
Signs of a leak you cannot see
Hidden leaks give hints long before they show water.
- Meter keeps movingTurn off every fixture and appliance, then watch the meter. A moving dial or a flowing leak indicator means water is escaping somewhere.
- Unexplained high billA bill that jumps with no change in habits is the most common first sign.
- Warm spot on the floorHot water lines under a slab can warm the surface above them.
- Sound of running waterA faint hiss or trickle in quiet rooms when nothing is on.
- Stains and musty smellBrown rings on a ceiling or a damp odor in a closet point to moisture inside the wall.
How a leak is found without opening everything
Method matters. Each tool narrows the search and saves demolition.
- 1
Test the system
Pressure and meter checks tell us whether the leak is on the supply side, inside the home or in a fixture.
- 2
Listen
Acoustic ground and wall microphones pick up the sound of escaping water through concrete and drywall.
- 3
Look for heat or moisture
A thermal camera and a moisture meter show temperature and wetness patterns behind surfaces.
- 4
Confirm before cutting
Two methods agreeing on the same spot justify opening a small access hole.
Hard water, high bills and your meter
Padre Dam Municipal Water District supplies Santee, and its 2023 water quality report lists hardness of roughly 9 to 18 grains per gallon depending on the treatment plant. Scale from hard water can foul shutoff valves, toilet fill valves and water heater fittings, and those are the places a slow leak often starts.
If your bill rises, read the meter at the curb, wait an hour with all water off and read it again. Any change means a leak, and that is the time to call before the next bill arrives.
Source: Padre Dam Municipal Water District, 2023 Water Quality Report.
Where leaks hide and how we confirm them
Most leaks come from a short list of places.
| Location | Typical cause | How we confirm |
|---|---|---|
| Toilet or fixture supply | Worn valve or connector | Dye test and visual check |
| Behind a wall | Failed joint or pinhole | Acoustic listening and thermal image |
| Under a slab | Pinhole in copper | Acoustic pinpoint, see slab leak repair |
| Between meter and house | Corroded or damaged line | Pressure test, see water service line repair |
A technician identifies the right tool for each case on site.
Guidelines the plumber follows to confirm a leak
A leak call starts with the water meter. The plumber closes all fixtures and reads the leak indicator, then isolates sections with shutoff valves. Acoustic and thermal tools narrow the location, and a pressure test confirms it before any wall or floor is opened.
Repairs that follow detection are made under the California Plumbing Code, which is based on the Uniform Plumbing Code (UPC). Keep the detection notes and photos, since insurers often ask for them.
What affects the cost of leak detection
Detection is priced by the search, not by the repair that follows.
Leak detection questions
Yes. Dispatch is open 24/7. For an active leak, shut off the main valve and call, and a licensed plumber is sent as soon as one is available, with same-day visits when possible.
Usually yes. Acoustic and thermal tools locate the spot, and any access hole is small and targeted.
Shut off the main valve at the house and watch the meter. If it still moves, the leak is between the meter and the house.
Coverage varies by policy and cause. Ask your insurer, and keep photos and the written findings we provide.
Yes. A slow toilet leak wastes a lot of water. Toilet repair often solves it with a new flapper or fill valve.
A burst pipe needs fast shutoff and repair. See burst pipe repair.