How to Find a Hidden Water Leak in Your Home

Not every leak is obvious. Many hide behind walls, under floors or inside fixtures, quietly raising your water bill and causing damage you cannot see.

The water meter test

Turn off every faucet, appliance and irrigation system. Write down the reading on your water meter, wait one to two hours without using any water, and check again. If the reading changed, you have a leak.

Common signs of a hidden leak

• An unexplained increase in your water bill
• Stains, bubbling paint or soft spots on walls and ceilings
• A musty smell or visible mold
• Warm spots on the floor (a possible slab leak)
• The sound of running water when nothing is on

Check the usual suspects

• Toilets — add a few drops of food coloring to the tank; color in the bowl after 15 minutes means a leaking flapper.
• Under sinks — look for moisture around supply lines and shut-off valves.
• Water heater — check for rust or water around the base.
• Outdoor spigots and irrigation lines — look for soggy patches in the yard.

What to do next

For an active leak, close the main water shut-off valve right away. If a shut-off valve is damaged or will not close, call a plumber — we are available 24/7 and replace failed valves regularly.