How to Use Your Water Meter to Check for a Hidden Leak

Use the meter as a clue, not a diagnosis

A water meter records water moving through the service line. If all water-using fixtures are off and the meter still moves, water may be flowing somewhere on the property. That can point to a leak, but it does not identify the location or establish responsibility for a repair.

Meter faces vary. Some have a small leak indicator, while smart meters may show use in an online portal. Your utility can explain its meter type and reading schedule.

Run a quiet-household test

Choose a time when no one needs water. Turn off faucets, irrigation, appliances that use water, and ice makers if practical. Do not run a dishwasher or laundry. EPA’s WaterSense guidance suggests recording the meter, waiting two hours with no water use, and checking it again. Photographing the display can make the comparison easier.

If the reading changes, repeat the test to rule out normal household use. A toilet that quietly refills, a dripping fixture, irrigation equipment, or a line issue can all add up.

• Check toilets by putting a few drops of food coloring in the tank; if color appears in the bowl after 10 minutes, flush and investigate the leak.
• Look under sinks and around water heaters for moisture.
• Inspect irrigation zones and outdoor spigots.
• Call a qualified plumber for work beyond your comfort level.

Narrow the problem without disturbing utility equipment

Denver Water describes a simple way to tell where a leak is. With all water turned off, close your home’s main shutoff valve and watch the meter. If the meter stops, the leak is inside the house, and toilets are the most common source. If it keeps moving, the leak may be in the underground service line between the meter and the house.

Only use the main shutoff if it is accessible and you know how to operate it safely. Do not open meter boxes, tamper with a meter, or operate a utility-owned valve. The utility can explain where its responsibility ends and the customer’s service line begins for that property.

How much water a small leak can add

Small leaks add up. EPA says the average household’s leaks can waste more than 9,300 gallons a year, and that a faucet dripping once per second wastes more than 3,000 gallons a year. EPA also offers a winter check: if a family of four uses more than 12,000 gallons a month in January or February, there could be a serious leak. WSSC Water says a small toilet leak can waste about 200 gallons a day.

Protect the record if you find a problem

Take dated photos of the meter and the repair area, and retain invoices. If you plan to ask about a leak adjustment, those records can be useful. Each utility sets its own eligibility rules, documents, time limits, and review process.

Report public-side leaks quickly

Water surfacing in the street, around a hydrant, or near a meter box may be a utility emergency. Keep clear of the area and report it using the provider’s emergency number; do not attempt to open utility equipment yourself.