Supply leak or drain leak? Why the difference matters
A supply line is under pressure all the time, so it leaks whether anyone is using water or not, and it turns the water meter. A drain line only leaks when water runs down it: after a shower, a bath or a flush. The meter test tells them apart in minutes.
This is the first thing we settle, because the methods are different. Pressurized leaks can be heard and pressure-tested; drain and shower leaks are found by running water through one fixture at a time and watching where the moisture appears.
Think you have a leak? Call and tell us what you’re noticing in your Greenwood home.
(877) 729-0265How we find a leak inside a wall or ceiling
- Meter testWith all water off, a moving meter means a supply leak; a still meter points to a drain, shower or appliance leak.
- Moisture mappingPin and pinless moisture meters measure how wet the drywall, wood and subfloor are, and where the wettest point is.
- Thermal imagingEvaporating water cools a surface and hot-water leaks warm it, so a thermal camera shows the shape of the wet area behind the finish.
- Fixture-by-fixture testsFor drains and showers, we run one fixture at a time, or flood-test a shower pan, and watch which one feeds the wet spot.
- Mark the sourceThe leak is marked on the wall or ceiling with notes and images, so the repair opening is one small, well-placed hole.
What you’re noticing and what it usually means
| Clue | Most likely source |
|---|---|
| Ceiling stain under a bathroom, worse after showers | Shower pan, valve, tub drain or grout |
| Stain that grows even when nobody uses water | Pressurized supply line in the ceiling or wall |
| Bubbling paint low on an outside wall | Hose bib or sink supply line, often freeze damage |
| Water on the floor around a toilet | Wax ring or supply connection; see toilet leaking at the base |
| Musty smell with no visible water | Slow leak in a crawl space, wall cavity or under flooring |
While you wait for the visit
- If the ceiling is bulging or sagging, put a bucket underneath and carefully puncture the lowest point to let water drain in one place.
- If the meter is moving, close the main shutoff when you aren’t using water. See how to shut off the water to your house.
- Stop using the shower or fixture you suspect.
- Take photos of stains and readings for your insurance claim.
Once the source is marked, our plumbing partner can fix it through one small opening. See leaking pipe repair in Greenwood.
Hidden Water Leak Detection: questions from Greenwood homeowners
How do you find a leak inside a wall without tearing it open?
We combine a meter test, moisture meters, thermal imaging and, for pressurized lines, acoustic listening and pressure testing. The leak is marked so only one small opening is needed for the repair.
Why is my ceiling leaking only after someone showers?
A leak that appears after showers but not otherwise is usually a drain, shower pan, valve or grout problem, not a supply line. A flood test of the pan and fixture-by-fixture testing finds it.
Can a thermal camera see through walls?
No. It sees temperature differences on the surface. Wet drywall is usually cooler than dry drywall, and a hot-water leak warms it, so the camera shows the shape of the wet area behind the finish.
Is a musty smell a sign of a hidden leak?
Often. A slow leak in a wall, crawl space or under flooring keeps materials damp enough to grow mold long before a stain shows. Moisture readings confirm it.
Do you serve both ZIP codes in Greenwood?
Yes, 46142 and 46143, from our base in Bargersville just south of the city.
Guides that go deeper
Sources: Indiana American Water; Town of Bargersville Water Utility; Indiana 811; Indiana Administrative Code, Title 327. Updated October 1, 2026.