Why start at the meter
A meter measures every drop that enters your property. If it moves when nothing should be using water, water is going somewhere. Many meters have a small leak indicator, a triangle, star or tiny dial, that spins with even a slow leak.
Your meter is usually in a concrete box near the street. The lid can be heavy and may have spiders or water inside, so lift it carefully with a tool rather than your fingers.
The basic meter test
- Stop all water use.Turn off every faucet, shower, irrigation controller, ice maker and appliance. Make sure no toilet is refilling.
- Read the meter.Watch the leak indicator for a couple of minutes, or note the full reading and check again after an hour with no use.
- Close the house shutoff.If the indicator moves, close the main at the house and watch again.
- Interpret.If it stops, the leak is inside the house or on a branch after the shutoff. If it keeps moving, the leak is on the service line between the meter and the house.
Narrowing it down inside the house
| Test | If the meter stops | If it keeps moving |
|---|---|---|
| Close all toilet angle stops | A toilet fill or flapper leak is likely | Move on to the next test |
| Close the water heater cold inlet | The leak is on the hot side, often under the slab or in a wall | The leak is on the cold side or elsewhere |
| Turn off the irrigation supply valve | The leak is in the irrigation system | The leak is in the house plumbing |
| Close the washer and fixture stops | One of those fixtures or lines is leaking | Suspect a pipe in a wall, ceiling or slab |
Signs that point to a wall or slab leak
- Warm patches on the floor after the hot-side test points there
- Stains or soft spots on drywall near plumbing walls
- Running water sound with everything off
- Mold or musty smell in one room
- A higher water bill than the same months last year
Common questions
My meter has no leak indicator. What do I do?
Write down the full reading, avoid all water use for an hour or two, and read it again. Any change means water is being used somewhere.
Does a toilet leak count as a broken pipe?
No, but a running toilet can waste water and makes meter tests confusing, so rule it out first.
Who do I call if the leak is before the meter?
Call the City of Fullerton water utility. Leaks at or before the meter are usually on the utility's side.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.