What this test can tell you
Your water meter measures everything that passes into the property. If it moves when nothing is supposed to be running, water is escaping. By closing valves one at a time and watching the meter, you can narrow the leak to the irrigation system, the line between the meter and the house, the toilets or the plumbing inside.
It takes about an hour, most of which is waiting. Pick a time when nobody needs water.
Recording sheet
| Stage | Start reading | End reading (after 15 min) | Moved? |
|---|---|---|---|
| 1. Everything off, all valves open | Yes / No | ||
| 2. Irrigation valve closed | Yes / No | ||
| 3. Main house shutoff closed | Yes / No | ||
| 4. Main open, toilet stops closed | Yes / No | ||
| 5. Main open, water heater cold inlet closed | Yes / No |
Run the test
Stage 1
Turn off all faucets, appliances, the ice maker and irrigation. Read the meter, wait 15 minutes, read again.
Stage 2
If it moved, close the irrigation valve and repeat. If it stops, the leak is in the irrigation.
Stage 3
If still moving, close the main house shutoff. If the meter stops, the leak is inside the house. If it keeps moving, suspect the line between the meter and house.
Stage 4
Reopen the main and close every toilet stop. If the meter stops, a toilet is leaking.
Stage 5
Reopen the toilets and close the water heater's cold inlet. If the meter stops, the leak is on the hot side, possibly under the slab.
Reading your results
- IfStopped at stage 2ThenLook for wet spots, broken heads or a leaking irrigation valve.
- IfStill moving at stage 3ThenThe main line from the meter may be leaking; see the main line guide.
- IfStopped at stage 4ThenDye-test each toilet to find which flapper is leaking.
- IfStopped at stage 5ThenA hot water line is likely leaking; call for leak detection.
- IfMoved through stage 5 but stopped at stage 3ThenThe leak is inside on the cold side; a plumber can pressure test the lines.
Share these results with a plumber
- At which stage did the meter stop?
- How much did it move in 15 minutes at stage 1?
- Are there any warm floors, damp walls or wet patches in the yard?
Common questions
Where is my water meter?
Usually in a box in the ground near the street or sidewalk in front of the house.
What if my water heater cold inlet will not close?
Skip stage 5 and tell the plumber. A stuck valve is worth replacing anyway.
Is a tiny movement worth worrying about?
Even small continuous leaks add up and can damage a slab or wall over time. It is worth tracking down.
General information for La Palma, not a quote or professional advice. In an emergency, call 911.