A hidden water leak runs where you can't see it: inside walls, under floors, or above ceilings. The clues are a meter that moves with everything off, brown stains, paint that bubbles, a musty smell, or flooring that warps. Start with the two-minute meter test below, then call us if the meter won't sit still.
The two-minute meter test
This is the test we run first on almost every call, and you can run it yourself right now:
- Turn off every faucet, shower, appliance, and your irrigation. Make sure the dishwasher and washing machine aren't running.
- Go to the water meter box at the curb and lift the lid.
- Watch the small leak-indicator dial. Usually a little triangle or star. Or the digital readout.
- If it moves at all, water is leaving your system. You have a leak somewhere. If it's dead still, your supply lines are holding.
That's it. Two minutes, no tools, and it answers the biggest question: is there actually a leak?
What hidden leaks leave behind
Water you can't see still leaves evidence. Walk your house and look for:
- Brown or yellow stains on ceilings and walls. Rings mean it's been happening a while.
- Paint that bubbles or peels in one area. That's moisture pushing from behind.
- A musty smell in a bathroom, closet, or along a wall. Trust your nose; mold announces itself before your eyes catch up.
- Flooring that warps, buckles, or feels spongy in one spot.
- A warm patch on the floor. That's a hot-water line, and it points to our slab leak checks.
- The sound of water running when every fixture is off.
Where we look first in Citrus Heights homes
Most local homes went up around 1977 with similar layouts, so the usual suspects are predictable: bathrooms that sit back-to-back sharing a wet wall, the kitchen sink wall, the laundry hookup box, the water heater closet, and pipe runs through the attic. We check these zones with a moisture meter first. It reads dampness inside drywall without opening anything, and only then decide whether thermal imaging or acoustic listening is needed to nail the exact spot.
Some leaks never show water at all. A mystery leak is the one you only know from the bill or the meter. No puddle, no stain, just usage that climbs. We check plumbing fixtures first: toilet bases, faucet supply lines, and shower valves, since a slow fixture leak can feed a wall for months before it shows.
Tools that see through walls
Three instruments do the real work, and none of them damage anything:
- Pin and pinless moisture meters map how far water has traveled inside a wall or under flooring, which tells us the direction it came from.
- Thermal imaging cameras show temperature differences. Wet areas read cooler (or warmer, on a hot line) than dry surroundings.
- Acoustic listening devices hear the hiss of pressurized water through drywall and slab, and the pitch changes as you close in on the break.
Between the three, we can usually mark the leak's location within inches before a single cut is made. Call (123) 456-7890 and tell us what you're seeing. We'll bring the right gear the first time.
Frequently asked questions
How can I tell if water is leaking behind a wall?
Look for brown stains, bubbling or peeling paint, a musty smell, or a wall that feels cool and damp. Then run the meter test: everything off, watch the meter. If the dial moves, water is escaping somewhere in the system.
Can a water leak go unnoticed for months?
Easily. A slow supply-line leak inside a wall or under a slab can run for months with the only symptom a gradually climbing water bill. That's why an unexplained bill increase is always worth investigating, even when everything looks dry.
Will you have to tear open my walls to find the leak?
No. Moisture meters, thermal imaging, and acoustic listening pinpoint the leak first. Any opening we make is small and exactly where the instruments point. Not exploratory demolition.
Is a musty smell always a leak?
Not always, but it's one of the most reliable early warnings. Musty means mold or mildew is growing, and that needs sustained moisture. If the smell is localized to one area, there's very likely water getting in there.
What should I do first if I suspect a hidden leak?
Run the two-minute meter test above. If the meter moves, shut off the main valve if you're worried about active damage, take photos of any stains for your records, and call us. Don't wait for the stain to grow. It only gets more expensive.
Related
- Water leak detection service
- Slab leak signs and repair options
- Ceiling and wall leaks
- Underground water leak detection
- How leak detection works
- Frequently asked questions
Think you have a leak?
Call AquaTrace Leak Detection to describe what you are seeing in Citrus Heights and get a plan to find it.
Call (123) 456-7890Last updated: October 25, 2026.