Active leak in the house, what to do
Water showing up on a ceiling, a wall or a floor is urgent, and we dispatch plumbers 24/7 to find the source. Your job in the meantime is to limit the damage and give us a clear picture of what you see.
Work through these steps in order.
- Shut off the main water valve, usually near the street side of the house or at the meter box. Turn a round handle clockwise until it stops, or turn a lever crosswise.
- Open a faucet at the lowest point of the house to drain pressure from the pipes, and watch whether the stain stops growing.
- If water is near outlets or a light fixture, turn off the breaker for that area before you touch anything wet.
- Take a photo of the stain or wet area, note the time, and call (855) 575-2890.
A ceiling that sags or bulges holds water above it. Poke a small hole in the lowest point with a screwdriver and set a bucket under it, so the ceiling does not fail on its own.
What leak detection is and why it matters
Leak detection is the process of finding where pressurized water or drain water escapes from a pipe you cannot see. In Los Gatos homes with crawlspaces, slabs, hillside lots and buried service lines, the pipe is rarely in sight, so a plumber who guesses will open the wrong wall.
A good search narrows the possibilities first. It begins with simple questions about when the problem began and what changed, then moves to tests that isolate one section of pipe at a time. Cutting into drywall or concrete comes last, and only at the spot the tests identify.
Not sure where the water is going? Call (855) 575-2890 and tell us what you have seen, a meter reading, a stain or a warm floor.
Call (855) 575-2890Meter still running with everything off
The water meter is the simplest leak detector you own. Turn off every fixture, the ice maker and the irrigation, then look at the meter. Most meters have a small triangle or dial that spins when water moves. If it turns with nothing running, water is escaping somewhere past the meter.
To find out which side, close the main valve at the house and watch the meter again. If it stops, the leak is inside the house or on the house side of that valve. If it keeps turning, the leak is between the meter and the valve, in the buried service line.
That single test cuts the search in half. It also tells us whether to bring listening gear for walls and floors, or equipment for an underground run. Keep in mind that a toilet flapper that leaks slowly can also turn the meter, so we check those first.
A high water bill without a visible leak
A bill that rises with no change in how you live is a common first sign. Compare it to last year's same months, since irrigation can add to summer use. If usage is up by a large margin and nothing explains it, a leak is likely.
A running toilet is the most frequent culprit and costs nothing to rule out. Drop a few drops of food coloring into the tank and wait ten minutes. If color shows in the bowl without flushing, the flapper is leaking.
If the toilets pass, the meter test above comes next, followed by a pressure test on the house lines.
Stain on the ceiling or wall
Water travels. A brown ring on a ceiling is seldom directly under the leak, because water follows a joist or a pipe before it drips. The stain shows where the water gave up, not where it began.
Common sources include a leaking supply line in the attic or wall, a failed shower pan or tub drain on the floor above, and a loose toilet supply. A thermal camera shows cool, wet areas behind drywall as colored patterns, and a moisture meter confirms them. That lets us cut a small, neat hole instead of a large one.
If the leak is a burst or fast-spraying pipe, treat it as urgent and see burst pipe repair.
Leaks under the house or in the crawlspace
Homes on raised foundations have copper or galvanized supply lines and cast iron or ABS drains hanging under the floor. A leak there shows up as a damp spot on the soil, musty air, buckled hardwood or a floor that feels soft.
We crawl in, look at every joint and hanger, and listen to the pipes with an electronic ground microphone. Drain leaks are found with water tests and a camera. Pipe wrap and insulation that is damp or discolored often marks the spot.
Do not enter a crawlspace that has standing water near wiring. Call us and describe what you see from the access hatch.
Buried lines and leaks outside
The line from the meter to the house runs underground, often under a lawn or driveway. A leak there can go unseen for months, then show up as a soggy patch, a sunken area or lush green grass in one strip.
We find these leaks with acoustic listening on the pipe, line tracing and sometimes tracer gas, which is a harmless gas that rises through soil to the surface. Once the spot is found, repair planning moves to water service line repair.
Irrigation leaks are common too. A zone that stays wet after it shuts off, or a valve box full of water, points to a stuck valve or a broken line. A pool or spa leak is its own kind of search, and if the pool loses water faster than evaporation, a pressure test on its lines is the starting point.
Ground near Los Gatos Creek or the Los Gatos Creek Trail corridor can stay damp on its own, so a meter test is a better first clue than a wet patch. We search for leaks across Santa Clara County in ZIP codes 95030, 95031, 95032 and 95033.
Which leak-finding method fits which problem
No single tool finds everything. This is how we usually match the method to the symptom.
| Symptom | Method | What it shows |
|---|---|---|
| Meter turns with everything off | Meter and main-valve test | Which side of the house valve the leak is on |
| Hissing or warm spot on the floor | Acoustic listening | The sound of water escaping, pinpointed on a pipe |
| Stain on ceiling or wall | Thermal imaging and moisture meter | The wet area behind the surface |
| Pressure drops when lines are isolated | Pressure test by section | Which branch of the plumbing is leaking |
| Wet patch in the yard | Line tracing and tracer gas | Where the buried pipe is losing water |
Drain and sewer leaks use water tests and cameras instead, since those lines are not pressurized.
What a Los Gatos leak search looks like
We start by asking questions on the phone and noting what you have seen. On site, we confirm the symptom, run the meter test, and then isolate sections of pipe with test caps and a gauge. A line that holds pressure is cleared, and one that falls is where we keep looking.
We aim for the smallest opening that confirms the leak. Once we find it, we explain what is wrong, show you the damaged pipe and lay out options before we repair anything.
Hard water can matter here. San Jose Water's 2025 report shows hardness varying from about 99 ppm in treated Valley Water to 288 ppm in groundwater, depending on the source. Ask your water utility which source serves you, and mention any green crust or white scale you see at pipe joints, since it helps us read the age and condition of the plumbing.
What drives the cost of finding a leak
We cannot name a figure before knowing the symptom, but these are the factors that shape the price.
Where the leak might be
A fixture supply is quick to test. A leak under a slab or in a long buried run takes longer.
Equipment needed
Listening gear, thermal imaging, pressure testing and tracer gas each add time to the visit.
Access
Open crawlspaces and garages are simple. Finished walls and tight attics slow the search.
Number of leaks
Older pipe often leaks in more than one spot, and finding all of them takes extra time.
Repair after detection
Finding the leak is one job. Opening and fixing it is another, and you get the repair price before we start.
Insurance may help with the water damage from a sudden leak, and some policies include the cost of access to find the source. Slow leaks from wear or corrosion are often excluded, so read your policy or ask your agent.
Want your real number? Call (855) 575-2890. We give a clear price before work starts.
Planning the repair after the search
Once the leak is found, the repair depends on the pipe and its location. A single pinhole in a copper line can be cut out and replaced with a short section. If the whole run is pitted, a partial repipe may cost less over time than repeated repairs.
For leaks under concrete, we compare a spot repair through the slab, rerouting the line through the walls or attic, and a repipe. Each has trade-offs on disruption, cost and lifespan, and we explain them plainly. If you are curious about how that decision works, read about slab leak repair.
If you live in Monte Sereno or elsewhere in our area, the same meter test tells us early whether the buried line is involved.
Questions about hidden leaks in Los Gatos
Yes. Dispatch runs 24/7. If water is actively spreading, shut off the main valve and call. We do not promise an arrival time, but same-day appointments are offered when available for less urgent cases.
Turn everything off and watch the water meter. If it moves, water is escaping. If it holds still, the high bill probably comes from usage like irrigation or a seasonal change.
Yes. We use electronic listening devices, thermal imaging, moisture meters and pressure testing, and we pick the method that fits the symptom.
Often we can narrow the spot enough to cut only a small access hole. We do not open walls to look around. Some leaks do require access to confirm, and we tell you before we cut.
Start with the meter and the main shutoff valve. That tells us whether the leak is inside the house or in the buried line, and everything else follows from there.
We can test irrigation lines and pool plumbing for pressure loss. Tell us on the call so we bring the right gear.
It depends on the policy and the cause. Some policies cover access costs for a sudden leak, while slow corrosion leaks are often excluded. Ask your agent.