Home › Advice › Hidden Leak? Run This Two-Hour Water-Meter Test

Hidden Leak? Run This Two-Hour Water-Meter Test

By Mark Phaneuf · Updated August 21, 2026 · Editorial policy

A water meter can answer one narrow but valuable question: did water move through the service while everything was supposed to be off? It cannot locate the leak by itself, but it can turn a vague high bill or damp smell into a documented fact.

Stop before testing if water is actively damaging the home

Do not spend two hours on a meter test when you have active water near electrical equipment, a sagging or bulging ceiling, sewage, rapidly spreading water, or a burst supply line. If it is safe, use your main water shutoff plan, protect people from the area, and call the appropriate utility or licensed professional.

Do not enter a flooded crawl space, touch a wet panel or outlet, or lift a heavy street-side meter lid that belongs to the utility.

Prepare a true no-use window

EPA WaterSense recommends comparing meter readings across a two-hour period with no water use. The test only works if “no use” is real.

Before the first reading:

• tell everyone in the home not to use sinks, toilets, showers, tubs, ice makers, or appliances;
• pause irrigation and water features according to their controls;
• avoid running a dishwasher, washer, water softener, humidifier, pool fill, or automatic cleaner;
• do not start the test while a toilet tank is refilling;
• note any appliance that uses water automatically.

If you cannot control all water use, choose a different time rather than interpreting a contaminated test.

Read the meter without guessing

Find the meter. EPA notes that it is often underground near the curb, but it may be inside a basement or utility area. Follow your utility's instructions for access. Some utilities prohibit customers from opening or operating parts of the meter assembly.

Photograph or write down:

• every displayed digit;
• the unit—often gallons or cubic feet;
• the position of any flow or leak indicator;
• date and exact time;
• whether an irrigation meter or separate submeter exists.

Do not turn utility-owned valves or force a stuck lid.

Wait two hours with no water use

Leave everything off. After two hours, take the second reading from the same angle.

• No change: the test did not detect continuous or scheduled water use during that window. Intermittent leaks can still exist.
• Any change: WaterSense says you probably have a leak. First verify that no person or automatic device used water.
• Large or accelerating change: treat it as more urgent, especially with dampness, audible flow, foundation water, or a sudden bill spike.

Keep both photos. If the meter reports cubic feet, a small leak may be harder to see over a short interval; follow utility guidance rather than converting or extrapolating a dramatic estimate from a tiny change.

Isolate only owner-visible sources

Work from simple observations:

1. Listen for toilets that refill on their own.
2. Look under sinks and around supply connections for moisture.
3. Check appliance pans and accessible hoses.
4. Inspect outdoor hose bibs and irrigation areas.
5. Note damp soil, warm floor areas, wall staining, musty odor, or a sound of water when fixtures are off.

EPA suggests a food-coloring toilet test, followed by flushing promptly to avoid staining. Follow WaterSense's current instructions. Do not remove wall finishes, dig, pressurize piping, or use electrical equipment in wet areas to hunt for the source.

What to send the plumber or utility

Provide:

• both timestamped meter photos;
• the two readings and units;
• confirmation of the no-use controls;
• recent bills compared with the same season;
• locations of sounds, stains, odors, warm spots, or damp soil;
• whether the shutoff changes the observed flow, if a professional or utility instructs you to test it;
• any leak-alert history from a monitoring device.

This helps separate fixture leaks, irrigation, equipment, the private service line, and a possible utility-side issue without pretending the meter identified the source.

Add the meter location and reading instructions to your seasonal home maintenance schedule and keep your shutoff labeled before the next emergency.

Quick answers

How can I use my water meter to check for a hidden leak?

EPA WaterSense recommends reading the meter, using no water for two hours, and reading it again. Any change probably indicates a leak, but first account for appliances, irrigation, occupants, and automatic systems that may have used water.

Does a moving meter tell me where the leak is?

No. It establishes that water likely moved somewhere after the meter. Toilets, irrigation, fixtures, appliances, service lines, and hidden piping still need to be isolated safely.

When is a hidden leak an emergency?

Treat active water near electricity, a bulging ceiling, structural movement, sewage, rapidly spreading water, or loss of safe water service as an urgent stop-and-call condition.