Leak detection: the short answer
If your water bill jumped, you hear water running when nothing is on, or you find damp drywall, a stained ceiling, warped flooring or a musty smell, a hidden leak is likely. A simple water meter test can confirm a leak in about half an hour. A plumber can then pinpoint it with acoustic, thermal or moisture tools, so less of the wall or floor has to be opened. Call (207) 555-0163 to speak with a local plumber in the Portland area.
Signs of a hidden leak
- a water bill that's higher than usual with no change in habits
- the sound of running or dripping water inside a wall or ceiling
- stains, bubbling paint or soft drywall
- warped, cupped or loose flooring
- a musty smell or mold in one spot
- a toilet that refills on its own between flushes
For other problems, see our overview of Portland plumbing services.
Check your water meter first
Turn everything off
No faucets, showers, toilets, dishwasher, washing machine, ice maker or water treatment equipment running.
Note the meter
Write down the reading, or watch the small leak indicator if your meter has one.
Wait without using water
Give it 15 to 30 minutes.
Check again
If the reading moved or the indicator is turning, water is going somewhere. Close the valves behind the toilets and test again to see whether a toilet is the culprit.
Your water utility depends on where you live: Portland Water District serves Portland and South Portland, Maine Water serves Biddeford and Saco, and the Yarmouth Water District serves Yarmouth.
How urgent is it?
Active dripping through a ceiling is urgent. A slow hidden leak still shouldn't wait.
A leak you can see coming through a ceiling or wall calls for shutting off the water and calling now. A slow leak inside a wall can quietly rot framing and grow mold, so book a visit within days, not months.
How plumbers find hidden leaks
- Acoustic listening to pick up the sound of escaping water in pipes behind walls and floors.
- Thermal imaging to spot temperature differences where wet materials or hot water lines are leaking.
- Moisture meters to map how far the water has spread.
- Pressure testing to isolate which line is losing water.
- Dye tests for toilet tanks, and cameras for drain lines.
Common leak spots in older Portland homes
Toilets, supply hoses, shower valves, water heater fittings and connections under sinks top the list everywhere. Older homes add a few more: pipes in exterior walls that froze and cracked during a past cold snap, old galvanized steel pipe corroding from the inside, and decades of repairs with mixed materials. Portland Water District notes that lead was used in household plumbing into the 1980s, even though its own service lines are lead-free, so a leak repair in an older home is a good time to ask what the rest of the piping is made of. See plumbing in older Portland homes.
What happens during a leak detection visit
History and meter check
Your bill, the signs you've seen and a meter test to confirm water is being lost.
Isolate the system
Hot or cold side, supply or drain, inside or outside the house.
Pinpoint
Acoustic, thermal and moisture tools to find the spot before cutting anything open.
Repair
Open the smallest possible area, fix the pipe or fitting and test.
What affects the cost
- Detection method and how long it takes to find the leak.
- Location: an open basement versus inside a finished wall, ceiling or under a floor.
- The repair itself, which is often priced separately from detection.
- Drywall and finish work, usually separate from the plumbing.
See the plumbing cost guide.
Questions to ask before you hire
- What tools will you use to find the leak before opening walls?
- Is the repair priced separately from the detection?
- Who patches the drywall or flooring afterward?
- Should other old piping in the house be looked at while you're here?
What to have ready when you call
- your recent water bills, if usage jumped
- where you've seen stains, damp spots or heard water
- the result of your meter test, if you did one
- the age of the home and any recent plumbing work