Use a two-hour water meter test to check unexplained water use, record the right units, interpret the results, and know when to call for help.
A water meter leak test checks whether water passes through your meter while all normal water use is stopped. Record the reading, avoid using water for two hours, and read it again. A change suggests a leak or overlooked use; it does not reveal the exact location by itself.
This guide is for homes with an individual, accessible water meter. If you share a meter with other homes, have a private well, or cannot safely access the display, ask your utility or property manager for the correct method. Do not open equipment or operate a utility-owned valve to perform this test.
When a meter test is useful
A test can help when your recorded consumption increases without an obvious explanation, you hear unexplained filling, or you want to check whether a repair stopped water loss. It is a screening step, not proof that a buried pipe is broken.
First distinguish a high dollar amount from high consumption. A longer billing period, a rate change, or an extra charge can raise the bill without extra water use. Compare the units consumed and the dates. The EPA explains common billing units and rate structures, including the difference between fixed and usage-based charges.
If you already see flooding or an active leak, do not spend two hours testing. Move away from unsafe conditions and seek appropriate help. Water around electrical equipment requires particular caution; do not enter a flooded area to reach a switch or appliance.
Step 1: identify the right meter and reading
Use your utility’s instructions to find the meter serving your home. An indoor display, a curbside box, and an online account are not interchangeable. A utility portal may update less frequently than the physical meter. If you cannot identify the correct meter or units, ask the utility before interpreting a number.
Do not lift a lid that is too heavy, reach into standing water, disturb wires, or put your hands into a box you cannot see clearly. Keep children and pets away from an open box. Replace any cover you are authorized to move, using the utility’s directions.
Write down the unit shown on the display. Gallons, cubic feet, and billing units are different quantities. One cubic foot is approximately 7.48 US gallons; 100 cubic feet, often shown as CCF or HCF on a bill, is about 748 gallons. Do not assume a final digit is a whole gallon or a decimal unless the display instructions say so.
Step 2: stop ordinary water use
Choose a quiet period and tell everyone at home that you are taking a reading. Finish normal tasks first, then avoid faucets, showers, flushing, laundry, and dishwashing during the observation period. Check for scheduled watering or equipment that can fill automatically.
Examples to consider include ice makers, water-treatment regeneration, irrigation timers, pool autofill, and automatic humidification. These are possibilities to check, not a claim that every home has them. Pause only normal user controls that you understand and are authorized to use. Do not disable fire protection, medical equipment, or unfamiliar building systems.
A useful preparation note has four items: the start time, meter reading, units, and any equipment that might still run. If someone uses water during the test, record that and restart when practical. A known interruption is better than an apparently precise but misleading result.
Step 3: observe and record
EBMUD’s leak-check guide describes looking for movement in a meter’s leak indicator after stopping water use. Some meters have a small dial or triangle; others have a digital flow display. Use the instructions for your meter, not a picture of a different model.
The EPA recommends comparing readings across a two-hour period with no water use. Photograph the display at the beginning and end if you can do so safely. Use the same display and units both times.
If you have only an online usage chart, check its reporting interval with the utility. A delayed chart cannot show whether a valve you just closed changed the flow immediately. Label a portal observation as such instead of treating it as a live meter reading.
Step 4: interpret the result without guessing
| Result | What it means | Next step |
|---|---|---|
| The reading increases and no intended use occurred | Water passed through the meter; an unseen leak or automatic use is possible. | Check accessible fixtures and ask the utility or a plumber about further diagnosis. |
| The reading increases, but equipment ran | The test includes that use. | Repeat under clearer conditions; do not label the entire difference a leak. |
| The reading appears unchanged | No change was detected at that display’s resolution during this interval. | Continue investigating if symptoms persist; intermittent or small losses may not show. |
| The display or units are unclear | The measurement is not yet interpretable. | Ask the utility to explain the reading. |
A useful record contains observations rather than a premature conclusion. Write “the gallon reading increased by 6 over 120 minutes” rather than “the underground pipe leaks.” The first statement helps someone diagnose the situation; the second assumes a location the test has not established.
A worked example: estimate flow, not a guaranteed bill
Suppose a meter clearly marked in gallons increases from 12,450 to 12,456 during a two-hour test. The measured difference is 6 gallons. Dividing by 2 gives an average of 3 gallons per hour during that interval.
If that same flow continued uninterrupted, it would amount to 72 gallons per day and 2,160 gallons over 30 days. These are calculations from a hypothetical reading, not a typical leak rate or a prediction for your home. A toilet that refills occasionally may not repeat the same pattern all day.
For an illustrative water-use charge of $5 per 1,000 gallons, 2,160 gallons would cost $10.80 in that charge alone. The $5 figure is an example, not a local tariff. Actual bills can include sewer charges, tiers, and fixed fees; use your utility’s current rate information rather than multiplying by a national average.
Where to look next
Begin with safe, visible checks: running toilets, dripping taps, damp supply connections, and outdoor fixtures. Do not open walls or dig simply because the meter changed. If a toilet refills without flushing, start with our running-toilet troubleshooting guide.
If you are unsure which toilet component does what, our flapper versus fill valve comparison explains the distinction before you buy a part. The broader Plumbing & Water section groups related guides.
EBMUD’s Looking for Leaks guide notes that intermittent losses may escape an observation and describes further isolation checks. Those checks require knowing the building’s plumbing arrangement. Ask for help if a shutoff is stuck, unfamiliar, shared, or connected to other essential systems. Do not operate a utility curb stop yourself.
Who should you contact?
Contact your utility about reading the meter, suspected problems with utility equipment, or unexplained billing. Ask a plumber about customer-side leaks and a property manager about shared or rental systems. Ownership boundaries vary: EBMUD describes its own boundary at the meter, but your local utility must confirm the rule for your address.
Before arranging paid leak detection, ask what the visit includes, whether locating and repairing are separate charges, and what access is needed. Keep photographs and repair records; if a leak-adjustment program exists locally, ask about its requirements rather than assuming a credit is automatic.
Frequently asked questions
Can a meter test locate the leak?
Not by itself. It indicates measured flow during a defined period. Further observation or professional isolation is needed to identify the source.
Does a still meter rule out every leak?
No. Consider the display resolution, the length of the observation, and whether the fault occurs only when equipment operates. Persistent signs still deserve investigation.
Can I do this in an apartment?
Only if you know the meter serves your unit and you can safely observe it. On a shared meter, other residents’ use makes a no-use test unsuitable without coordination.
Should I shut off the main supply for the first test?
No: the basic observation compares readings while ordinary use is stopped. Closing the supply changes what the meter can measure. More advanced isolation should follow local instructions and the actual plumbing layout.
Illustrative feature photo by Imani on Unsplash. The photograph shows ordinary water use, not a diagnosed leak. Research reviewed September 12, 2026. See our Editorial Policy.
