Set up a reliable no-use check
- Ask everyone in the home not to use sinks, toilets, showers, or appliances during the observation period.
- Pause irrigation and confirm it is not between visible spray cycles; a leaking valve may pass water without a sprinkler head rising.
- Account for ice makers, reverse-osmosis systems, water softeners, humidifiers, pool autofill equipment, and any appliance that can draw water automatically.
- Wait for toilet tanks to finish filling. A worn seal may let water enter the bowl until the fill valve switches on again, creating short bursts on the meter. EPA identifies flappers and fill valves as common sources of unintended household flow. [2]
What the movement pattern can tell you
What you see
What it may help you test next
A steady flow indicator
Look for a continuously open fixture, supply leak, irrigation leak, or equipment feed.
Movement every few minutes
Listen for a toilet refill or automatic device cycle.
Movement stops when one fixture valve closes
Inspect that fixture and its connections before looking for a whole-house leak.
Movement continues after accessible fixture branches are isolated
A concealed distribution pipe or private service line becomes more plausible and warrants targeted testing.
Check one water user at a time
Record the display
Take a clear photo or write down all visible digits and the position of any low-flow indicator. Note the exact start time.
Wait without using water
Use a long enough interval to reveal slow or intermittent flow. EPA's homeowner guidance describes comparing the meter before and after a no-use period. [1]
Isolate obvious users
Close accessible fixture or appliance valves one at a time only if they turn normally. Recheck the meter after each change so the result stays connected to one action.
Separate the building from the service line
When the private main shutoff is accessible and known to work, a plumber can compare meter behavior with the building isolated. That test can help distinguish indoor piping from the private service line between the meter and the building.
Restore what you changed
Return valves and controls to the intended position, then check the affected fixtures. Do not leave an appliance operating without its water supply.
The meter measures total water passing through one point. It cannot tell whether that water went to a toilet, irrigation valve, appliance, hot-water line, cold-water line, or underground service. Smart monitors can flag irregular flow and some can close a valve, but EPA notes that installation location, pipe type, household patterns, connectivity, and maintenance affect what a device can report. [2]
A useful service request includes whether movement was steady or intermittent, how long the no-use test lasted, which automatic devices were paused, and which shutoff changed the result. That sequence is more valuable than guessing that the leak is under the slab.
If you repeat the check, use the same no-use duration and pause the same automatic equipment. Record each valve position and restore it before moving to the next test. Changing several controls at once makes a stopped meter difficult to connect to one water user.