Leak detection
How to check your water meter for leaks
Updated · Editorial team; not yet technically reviewed
Short answer
Turn off every faucet and water-using appliance, find the meter's leak indicator (a small triangle, star or dial), and watch it. If it moves, water is flowing somewhere. Note the reading, wait 30 to 60 minutes without using water, and check again. Then close the house's main shutoff: if the meter still moves, the leak is in the service line between the meter and the house.
The test
Find the meter
Usually in a box near the street or sidewalk, or in a basement or utility room in cold climates.
Shut off all use
Faucets, irrigation, ice maker, water softener regeneration, pool fill.
Watch and wait
Note the indicator and reading; check again after 30 to 60 minutes.
Split the system
Close the house shutoff; movement now means the service line.
What the result means
| Result | Next step |
|---|---|
| Meter still with everything off | No active leak; check billing or meter accuracy |
| Moves, stops when house valve closed | Leak inside: toilets, faucets, water heater, slab |
| Moves with house valve closed | Service line leak; see leak detection |
Using it for a bill dispute
Photograph the readings with the date. Many utilities offer leak adjustments only after repair and with proof; see the high water bill problem guide.
Narrowing the leak down after the meter test
Once the meter shows a leak, close the house main shutoff and watch the meter again. If it stops, the leak is inside the house; if it keeps moving, the leak is in the service line between the meter and the house, which is usually the owner's to fix. Inside, start with toilets: add a few drops of food coloring to each tank and wait fifteen minutes without flushing. Color in the bowl means a leaking flapper, the most common cause of a moving meter.
Next, shut off the valve feeding the water heater and any irrigation system and recheck; then look at water softeners stuck in regeneration, refrigerator ice-maker lines and outdoor faucets. If none of these explains it, the leak is probably hidden in a wall or under the slab. A plumber with acoustic and thermal equipment can usually pinpoint it without tearing open large areas.
Common questions
What does the leak indicator on a water meter look like?
Usually a small red or black triangle, star or dial that spins with low flow.
How long should a meter leak test take?
Watch the indicator right away, then compare readings after 30 to 60 minutes of no use.
Can a water softener make the meter move?
Yes, during regeneration; make sure it isn't cycling during the test.
Where is my water meter?
Usually in a ground box near the street or sidewalk, or indoors in colder climates.
How do I tell a service line leak from an indoor leak?
Close the house shutoff; if the meter still moves, the leak is between the meter and the house.
Should I open the meter box myself?
Lifting the lid to read it is usually fine; don't tamper with the meter or its valve.
General information; codes vary by location. See our editorial standards.