Before you start
Pick a time when nobody needs water for about an hour. Turn off irrigation, make sure the dishwasher, washer and ice maker are idle, and check that no toilet is running.
Find the meter box, usually near the curb or sidewalk in front of the house. Lift the lid carefully and look at the dial. Most meters have a small low-flow indicator that spins with even a slight flow.
The test
Watch the low-flow indicator
With everything off, watch it for a minute or two. Note whether it moves.
Write down the reading
Record the full number on the dial and the time.
Wait 30 minutes
Use no water at all during this time.
Read it again
Any change means water is leaving the system somewhere.
Close the house valve and repeat
If the meter stops with the house valve closed, the leak is inside the house or under the slab. If it keeps moving, the leak is in the line between the meter and the house.
Check toilets
Put a few drops of food coloring in each toilet tank. If color shows in the bowl after 15 minutes without flushing, that flapper is leaking.
Results sheet
| Test | Start reading and time | End reading and time | Moved? |
|---|---|---|---|
| Everything off, house valve open | Yes / No | ||
| Everything off, house valve closed | Yes / No | ||
| Water heater cold supply closed | Yes / No | ||
| Toilet dye test, each toilet | Yes / No |
What your results mean
- IfMeter still with everything offThenNo significant hidden leak at the moment.
- IfMeter moves, stops when house valve closedThenLeak inside: a toilet, fixture, or a line in a wall or under the slab.
- IfMeter moves, stops when water heater supply closedThenLeak on the hot water side, a common sign of a slab leak in older homes.
- IfMeter keeps moving with house valve closedThenLeak in the service line between meter and house, or irrigation. Look for wet ground.
Tell the plumber
- Which steps made the meter stop moving?
- How much did the reading change in 30 minutes?
- Are there warm spots, damp areas or sounds of running water?
- How old is the house and its water lines?
Common questions
How small a leak can this test catch?
The low-flow indicator moves with very small flows, so even a dripping fixture can show up.
Is a running toilet enough to move the meter?
Yes, a leaking flapper can move it. That is why the dye test is part of the worksheet.
Do I need a tool to open the meter box?
Some lids lift by hand; others need a screwdriver or meter key. Watch for insects inside.
General information for Anaheim, not a quote or professional advice. In an emergency, call 911.