How to Find a Water Leak Before It Costs You Thousands
Meter tests, common hidden-leak locations, and the moisture meters and leak detectors worth owning.
Undetected leaks waste roughly 10,000 gallons per home each year nationally and are the most common cause of mid-five-figure insurance claims. Catching them early is mostly about knowing where to look.
The meter test
Shut off every water-using fixture in the house and check the small low-flow indicator on your water meter. If it spins at all over a 15-minute period with everything off, you have a leak somewhere on the supply side.
Next, close the main shutoff to the house and re-check. If the meter stops, the leak is inside; if it keeps moving, the leak is between the meter and the house — often in the buried service line.
Common hidden-leak locations
Toilet flappers are the single most common source of silent waste, leaking 100–200 gallons a day with no visible drip. A few drops of food coloring in the tank will show up in the bowl within 15 minutes if the flapper is bad.
Other usual suspects: pinhole leaks in copper supply lines (look for green corrosion staining), failing washing machine hoses, dishwasher drain hoses, and the rubber gasket on water heater inlet/outlet connections.
Quick checklist
- Test the toilet flapper with food coloring
- Check under every sink for moisture or mineral deposits
- Inspect washing machine hoses for bulging
- Watch for unexplained jumps in water bills
- Install leak-detection alarms near water heater and washer