Quick answer: To find a hidden leak: check your water meter with everything off — if it still moves, you have a leak. Then look for warm/wet spots on floors, stains on ceilings/walls, a spike in your water bill, the sound of running water, or mold smell. A cheap water leak detector near at-risk spots catches leaks early.
A licensed plumber’s method for finding leaks fast.
Step 1: The Meter Test
Turn off every water fixture and appliance. Check your water meter, wait 1–2 hours with no usage, and check again. If it moved, water is escaping somewhere.
Step 2: Hunt for Signs
- Stains or sagging on ceilings and walls
- Warm spots on the floor (hot-water line leak)
- Musty smell or mold
- Unexplained jump in the water bill
- Sound of trickling water with everything off
Step 3: Check the Usual Suspects
Toilets are the #1 silent leaker — add food coloring to the tank; if it shows in the bowl without flushing, the flapper is leaking (see our running toilet guide). Then check under sinks, the water heater, and supply lines.
Step 4: Prevent the Next One
Put water leak detectors near the water heater, washing machine, and under sinks. They alarm the moment water appears — cheap insurance against a flooded home.
When to Call a Plumber
If the meter confirms a leak but you can’t find it, it may be inside a wall or under the slab — call a pro with leak-detection equipment. For a burst you can see, our emergency pipe guide shows how to stop it.