Check a Water Meter for a Hidden Leak

Step 1: Make sure a meter check is the right next step

1. Use this check if you have a higher water bill, hear water running when nothing is on, see damp spots, or suspect a slow leak you cannot locate.
2. Wait until no one needs water for the next 15 to 30 minutes. Do not run a dishwasher, washing machine, irrigation system, humidifier, ice maker fill cycle, or water softener regeneration during the test.
3. If your home has a known automatic device that uses water on a schedule, pause it if you can so it does not confuse the reading.

If it works: You have a quiet test window with normal water use stopped.

If it doesn’t: If you cannot get a quiet window, try again later when the house and yard water use can stay completely off.

Step 2: Find the meter and read the leak indicator

1. Locate the water meter where the utility enters the property. It may be in a basement, crawlspace, utility area, or an outdoor meter box near the street.
2. Open the lid carefully if needed and clear enough dirt or condensation to see the face.
3. Look for a small leak indicator, sweep hand, or low-flow dial. Many meters have a tiny triangle, star, or needle that moves even with very small water flow.
4. Write down the full reading or take a clear photo so you can compare it later.

Step 3: Shut off all water use and watch for movement

1. Go through the house and make sure every faucet, shower, tub, hose bib, and appliance using water is off.
2. Listen for running toilets and make sure no fixture is slowly dripping during the test.
3. Return to the meter and watch the leak indicator for at least 1 to 2 minutes. Then compare the main reading again after 15 to 30 minutes if you want a stronger check.
4. If the indicator moves steadily or the reading increases while everything is off, treat that as evidence of a hidden leak or unintended water use.

Step 4: Isolate whether the leak is inside or outside the house

1. If your home has a main shutoff valve after the meter, close that valve to stop water to the house.
2. Watch the meter again for 1 to 2 minutes after the valve is fully closed.
3. If the meter stops moving with the house shutoff closed, the leak is likely somewhere in the home's plumbing or a fixture served by that line.
4. If the meter still moves with the house shutoff closed, the leak is more likely between the meter and the house, in an irrigation branch before the shutoff, or at the meter assembly itself.

Step 5: Check the most common hidden leak sources

1. Test toilets first. Put a few drops of food coloring in the tank and wait 10 to 15 minutes without flushing. Color in the bowl points to a leaking flapper or fill valve issue.
2. Check faucets, showerheads, tub spouts, refrigerator water lines, under-sink supplies, water heater relief piping, and hose bibs for slow drips or dampness.
3. Look for soft flooring, stained drywall, musty smells, warm spots on floors, or wet soil near the service line path.
4. If you have irrigation, make sure the controller is off and look for soggy patches or a zone valve that may be stuck open.

If it doesn’t: If nothing obvious shows up but the meter still moves, the leak may be in a wall, under a slab, underground, or in a fixture that only leaks intermittently.

Step 6: Restore service and confirm the result in real use

1. Reopen any shutoff valve you closed, slowly and fully, if it operated normally during the test.
2. Repair the leak you found or arrange further diagnosis if the meter test pointed to a hidden line leak.
3. After the repair or correction, repeat the meter test with all water off.
4. Then use water normally for a day or two and check that the meter no longer moves when the house is quiet and that your unexplained water use has stopped.

If it works: The meter stays still when water is off, and normal use no longer shows unexplained flow.

If it doesn’t: If the meter still moves after you fixed an obvious leak, continue isolating fixtures one by one or call a plumber or leak detection specialist for hidden piping diagnosis.