The meter is the best leak detector you own
Every gallon that enters the house passes through the water meter, usually in a concrete box near the curb. Most residential meters have a small triangle, star or dial that turns whenever water is moving, even a trickle too small to hear. If that indicator moves while everything in the house is off, water is going somewhere.
The test costs nothing and takes about half an hour. It will not pinpoint a leak under a slab, but it will tell you whether a leak exists, roughly how large it is, and which part of the property it is on. That information makes a later call to a plumber shorter and more useful.
How to run the meter test
- Turn everything off.Stop irrigation, the dishwasher, washer, ice maker and any running toilets. Ask the household not to use water during the test.
- Open the meter box carefully.Lift the lid with a tool rather than your fingers, and watch for spiders or standing water. Wipe the meter face so you can read it.
- Watch the leak indicator.If it turns, note how fast. Then write down the full reading and check again after 30 minutes without using water.
- Close the house shutoff.With the main valve at the house closed, look at the meter again. If it still moves, the leak is between the meter and the house, usually the yard service line or irrigation.
- Open the house shutoff and isolate.If the meter stopped when the house valve closed, the leak is inside. Closing toilet stops one at a time and the water heater's cold inlet can narrow it further.
Reading the results
| What the meter does | Most likely place to look |
|---|---|
| Moves with the house shutoff closed | Yard service line between the meter and house, or the irrigation supply. |
| Stops when a toilet stop is closed | That toilet's flapper or fill valve. |
| Stops when the water heater cold inlet is closed | The hot-water side, including a possible hot line under the slab. |
| Keeps moving with every fixture isolated | A cold line in a wall or under the slab, or a hose bib or valve leaking outside. |
| Moves only slightly over 30 minutes | Often a toilet; check with dye tablets before calling for leak detection. |
Quick checks before calling anyone
- Put food coloring in each toilet tank and wait 15 minutes without flushing; color in the bowl means a leaking flapper.
- Walk the yard for soft, green or sunken strips that line up with the path from the meter to the house.
- Look under sinks and behind the washer for drips at supply lines.
- Check hose bibs and the pressure regulator near the main for weeping fittings.
- Run the irrigation controller one zone at a time and watch for pooling or a stuck valve.
Good to know
- Typical meter location
- Concrete box near the curb or sidewalk
- Most common silent leak
- A worn toilet flapper
- Clue for a hot slab leak
- Meter stops when the water heater inlet is closed
- Who serves your address
- Shown on your water bill
Common questions
How long should I watch the meter?
Watching the indicator for a few minutes shows a large leak. A 30-minute reading with no water use catches small ones such as a slowly running toilet.
My meter does not have a leak indicator. What now?
Use the main dial instead: photograph it, wait 30 to 60 minutes without using water, and compare. Any change means water moved.
The leak is in the yard line. Is that a plumber or the city?
The line from the meter to the house is usually the owner's responsibility and a plumber's job. If the leak is at or before the meter, contact your water provider.
General information for La Mirada, not a quote or professional advice. In an emergency, call 911.