Before you start
Pick a time when nobody needs water for a couple of hours, such as an afternoon when the house is empty. Turn off irrigation at the controller, make sure the dishwasher and washer are idle, and check that no toilet is refilling.
Find your meter box near the curb and the main shutoff where the line enters the house. The meter belongs to Fullerton's city water utility; read it, but check with the city before operating the valve inside the box.
Test sequence
- Round 1: whole system.All water off. Record the full meter reading and whether the leak indicator moves.
- Round 2: wait.After at least an hour without using water, record the reading again.
- Round 3: house closed.Close the main house shutoff, wait, and record. Movement now points to the yard line or irrigation.
- Round 4: toilets.With the house open again, put food coloring in each toilet tank and check bowls after 15 minutes without flushing.
- Round 5: water heater.Close the water heater cold inlet, wait, and record. A change suggests a hot-side leak.
Reading log
| Round | Time | Meter reading | Indicator moving? | What was closed |
|---|---|---|---|---|
| 1 | Nothing, all fixtures off | |||
| 2 | Nothing, after waiting | |||
| 3 | Main house shutoff | |||
| 4 | Toilet dye test | |||
| 5 | Water heater cold inlet |
Reading the results
- IfNo movement in rounds 1 and 2ThenNo measurable leak right now. Recheck if the bill stays high.
- IfMovement continues with the house shutoff closedThenLook at the line between meter and house, and irrigation. A plumber can locate it.
- IfMovement stops with the house closed, and a toilet shows dyeThenRepair that toilet and test again.
- IfMovement stops when the water heater inlet is closedThenSuspect a hot-side leak, possibly under the slab. Call a plumber for leak location.
- IfMovement persists inside with toilets cleanThenCheck faucets, hose bibs and appliances, then call for professional leak detection.
Bring these answers to the plumber
- How fast was the meter moving between readings?
- Which round stopped the movement?
- Are any floors warm or damp near where lines run?
Common questions
My meter has no leak indicator. Can I still test?
Yes. Compare full readings over a longer interval, such as overnight, with no water use.
Is it safe to close the water heater inlet for the test?
Closing the cold inlet for a short test is generally fine. Avoid using hot water while it is closed and reopen it afterward.
Should I send this to the city?
If you are discussing your bill with the city, readings can be helpful. Check with the city about what they need.
General information for Golden Hills, not a quote or professional advice. In an emergency, call 911.