Hearing water running in the walls at night can be as simple as a toilet refilling from a slow leak or an appliance like an ice maker or water softener cycling. If none of those explain it, a hidden leak in a supply pipe or drain may be the cause.
Why You Notice It at Night
The house is quiet at night, so small sounds stand out. Fewer people are using water, which makes it easier to hear water that should not be moving. Sounds also carry through pipes and framing more clearly when everything else is still, so a small drip can seem louder than it is.
Common Harmless Causes
- A toilet refilling because of a worn flapper
- An ice maker filling its tray
- A water softener regenerating, often set to run overnight
- A dishwasher or washer on a delay timer
- Water draining from an upstairs fixture someone just used
Signs of a Hidden Leak
If the sound is steady, like a hiss or constant trickle, and none of the appliances are running, a supply line may be leaking. Other signs include warm spots on floors, stains on walls or ceilings, and a water bill that keeps rising.
An Overnight Meter Test
Before bed, make sure every faucet and appliance is off. Write down the reading on your water meter. Check it again in the morning before anyone uses water. If the reading changed, water is escaping somewhere. A little dye in each toilet tank, left for a few minutes, will show if a flapper is leaking into the bowl.
Note which wall the sound comes from and what rooms are nearby. That information helps narrow the search.
If the meter confirms a leak you cannot find, listening equipment and moisture tools can locate it inside the wall. For toilets or appliances that keep refilling, you can have a plumber fix the fixture causing it by calling (833) 603-1840.