You can check for a hidden leak yourself before calling anyone:
A moving meter doesn't prove a slab leak, since a running toilet can do it too, but it tells you it's time to call a plumber with leak detection equipment.
- Turn off every faucet, appliance, ice maker and the sprinkler system.
- Find your water meter in the box near the curb and lift the lid.
- Look at the small leak indicator (often a triangle or star) and write down the reading.
- Wait 10 to 15 minutes without using any water.
- If the indicator moved or the reading changed, water is going somewhere.
- Close the main valve at the house and check again. If the meter stops, the leak is inside the house or under the slab; if it keeps moving, it's between the meter and the house.


