Signs of a Hidden Water Leak

Smells and stains

Your nose is a fine leak detector. A musty, damp odour in a room that is normally fresh often means moisture is collecting where you cannot see it. Look for these visual clues as well:

• Brown or yellow rings on a ceiling below a bathroom.
• Paint that bubbles, peels or looks wavy on a wall.
• Baseboards that swell or separate from the wall.
• Flooring that cups, lifts or feels soft underfoot.
• Mould spots in cupboards under sinks.
• Warm patches on a floor that might mean a hot water line is leaking below.

Unusually high water bills with no change in habits are another strong hint.

The meter test

Your water meter will tell you whether water is moving when it should not be. It takes only a little planning.

1. Turn off every tap, fixture, and appliance that uses water. Make sure the dishwasher, washer, ice maker and any softener are idle.
2. Find the meter and note the reading, or keep an eye on the tiny spinning dial or triangle if your meter has one.
3. Wait an hour or two without using any water.
4. Check the meter again.

If the reading has changed or the indicator is turning, water is leaving the system somewhere. Next, close the main shutoff and watch again. If the meter still moves, the leak may be on the service line between the meter and the street, which calls for professional help.

The toilet dye test

A flapper that does not seal lets water trickle from the tank into the bowl around the clock. It is the most common silent leak in any house.

Drip some food colouring into the tank, leave the handle alone, and wait fifteen to twenty minutes. If colour shows up in the bowl, the flapper or the flush valve seat is leaking. Our guide to fixing a running toilet explains what to do next.

When to call

Some leak hunts end with a quick fix you can handle yourself. Others need specialized tools. Call for help when:

• The meter test shows a leak you cannot find.
• There is water in a ceiling, wall or floor.
• You see signs of mould or rot.
• A pipe is visibly corroded or weeping at a fitting.

Our leak detection service uses listening and thermal tools to narrow down where water is escaping, so repairs open as little of the house as possible. Older pipes may need repiping. If you suspect polybutylene supply line, read our Poly-B guide.

Keep an eye on the monthly water bill as well. Comparing it to the same month last year is a simple way to notice a slow change that day-to-day life hides.