How to check a water meter for leaks

What can your water meter tell you about a possible leak?

Shut off every fixture and appliance, note the meter’s reading or leak indicator, wait without using water, and look again. If the reading changes, water passed through the meter during the test. Confirm that no automatic device or other user was drawing water before treating it as evidence of a leak.

What the check can’t tell you is where. A moving meter could reflect a running toilet, an irrigation valve that won’t close, an automatic appliance cycle, or a broken pipe underground.

Where can you find the water meter safely?

Meters may sit in a box near the street or sidewalk, or in a building utility space. Locations and models vary by property, so use only a display you can access safely and are permitted to view.

• Look, don’t force. If the lid is locked, bolted, cracked or heavy enough to need a tool, stop.
• Watch for hazards. Meter boxes can hold spiders, standing water or sharp edges. Use a flashlight and gloves.
• Don’t operate utility-side valves. Use only an accessible, functional building shutoff you’re authorized to operate.
• Leave seals and wires alone. Never remove a tamper seal, register cover or radio transmitter.

If you can’t see the meter safely, call Public Works at 415-508-2130 for guidance rather than opening it yourself.

Digital vs. mechanical meters

If you’re not sure which part of your meter shows flow, take a clear photo and ask Public Works.

Prepare a no-water-use period

• Turn off every tap, shower and hose
• Make sure the dishwasher, washing machine and ice maker aren’t running or filling
• Pause the irrigation controller, or set it to “off”
• Wait until toilets have finished refilling
• Tell everyone in the building not to use water during the test
• Check that a softener, evaporative cooler or filter isn’t mid-cycle

Record the first reading, then wait and compare

Write down the date and time, the full meter reading (every digit), the sweep-hand position if you have one, the low-flow indicator state, and which fixtures were confirmed off. A photo helps you compare later.

1. Start the clock after taking your first reading and photo.
2. Watch the low-flow indicator for 5–10 minutes. Steady movement points to a flow happening right now.
3. Leave the water off for a longer stretch. EPA WaterSense recommends reading the meter before and after a two-hour period with no water use.
4. Take the second reading and a second photo, in the same format.
5. Compare. Any change in the register or sweep hand during the no-use window means water passed through the meter.

How to interpret movement cautiously

One useful follow-up: if your building has an accessible, working main shutoff you’re authorized to use, close it and observe the meter again. A change in movement helps identify which side of that valve is drawing water, but branch connections and shared meters can complicate the result. Never force a valve or operate the utility-side shutoff.

Toilets and automatic appliances to rule out

• Toilets: add food coloring to the tank, then leave it unflushed. Colored water in the bowl within about 10 minutes means the tank is leaking into the bowl (EPA WaterSense).
• Refrigerator ice makers and water dispensers can refill without warning.
• Water softeners and filters may run a regeneration cycle overnight.
• Evaporative coolers, humidifiers and boilers may add water automatically.

Irrigation schedules and common-area use

Check the controller schedule — a zone set to start mid-test will move the meter. A stuck valve can leak even when the controller is off; look for one wet area in a dry yard. Shared meters complicate things: in condos, townhomes or mixed-use buildings, one meter may serve several units or common landscaping, so check with your HOA or property manager first.

Why one test cannot locate the leak

A meter measures total flow at one point. It can’t see pipes. A steady reading change tells you water is leaving the system, not whether it’s a toilet flapper, a slab pipe, a wall pipe or a buried line. Isolating sections narrows the possibilities. Pinpointing a leak still takes investigation, and sometimes access.

When to call Public Works or Utility Billing

Contact Public Works at 415-508-2130 for City water infrastructure or meter-access concerns. Contact Utility Billing at 415-508-2154 for an account, billed usage or meter-reading question. Public Works can help when:

• You can’t reach or read your meter safely
• The meter itself looks damaged, leaking or tampered with
• Water appears at the meter box, curb or street
• A meter box or City-owned component appears unsafe or damaged

The City also offers a Residential Self-Audit Tool for tracking household water use, with free kits at City Hall on request. See why is my Brisbane water bill high? and city water main vs private property leak.

When a professional isolation check helps

• The meter keeps moving with fixtures, irrigation and appliances ruled out
• It still moves after you close the building shutoff
• Results stay unclear after repeated tests
• You see damp floors, stains or a wet patch outdoors alongside meter movement

Depending on the result, see water meter and pressure-loss investigation, underground water line leak detection or fixture leak detection.

Keeping a useful meter record

Example only. Your meter’s units and digits may differ.

Meter testing questions