Reading a Water Meter: Digits, Dials and Meter Number—and Spot a Leak

When reading a water meter, only certain digits count toward the reading you report to your water supplier: on an analog meter, these are only the black digits before the decimal point; on a digital meter, it is the digit before the decimal point on the display. The meter number, which uniquely identifies the meter assigned to your household, is located elsewhere on the casing and is often confused with the calibration year or the measuring range. If you also want to know whether water is escaping unnoticed somewhere in the pipes, you can check directly at the meter with a simple no-flow test, without needing a plumber.

• On analog meters, only the black digits before the decimal point count as the reported reading in whole cubic meters.
• On digital meters, the digit before the decimal point gives the whole cubic meters, while the digits after it provide a more precise reading.
• The meter number is usually in the upper part of the casing or on the rim where the cover rests, not next to the calibration year or measuring range.
• A no-flow test lasting 15 to 30 minutes, with all water-using appliances turned off, shows whether the meter continues to turn even when no water is being used.

How to read an analog water meter correctly

An analog water meter displays the reading on a number register with black and red digits. Only the black digits before the decimal point count for the reading reported to your supplier; they show consumption in whole cubic meters. The red digits and the places after the decimal point show liters or fractions of a cubic meter and are not included in the reported reading (source: SWD AG, How to read a water meter).

For example, if the register shows 01234 in black and 567 in red, report 1,234 cubic meters. The 567 are still useful for your own tracking, for example to monitor a small amount of consumption between readings, but they should not be included in the report. In most residential buildings, you will find the meter in the basement or utility room, or, in apartment buildings, at a central installation point, often behind a small hatch in the floor or wall (source: SWD AG, How to read a water meter).

How to read a digital water meter

Digital water meters display the reading on an LCD screen, which may activate only after a brief press of a button or turn on automatically, depending on the model. The same clear distinction applies here: the digit before the decimal point shows consumption in whole cubic meters, while the digits after it provide a more precise reading if you want to track smaller changes, such as 1,234.567 m³ (source: Hamburg Wasser, How to read a digital water meter). If the light is poor or the meter is deep inside a pit, a flashlight can help you avoid misreading the digits.

If the display instead shows “STOP,” the device is no longer measuring consumption. This is not an operating error, but a sign that the meter is faulty and needs to be replaced; in this case, you should contact your water supplier rather than trying to tinker with the device yourself (source: Hamburg Wasser, How to read a digital water meter).

Find the meter number and distinguish it from other information

The meter number is a combination of numbers or numbers and letters assigned uniquely to each device, allowing your water supplier to match it to your household. It is usually printed or stamped on the upper part of the meter casing (source: 42watt, Meter numbers for electricity, gas and water). On some models, it is instead on the rim where the cover rests when closed, so you can only see it when the cover is open (source: RheinEnergie, Meters and meter readings).

Do not confuse the meter number with other information on the casing: the calibration year indicates when the meter was calibrated, and the measuring range (shown as Qn with a flow rate) describes the technical performance class, not the identity of the device. A simple check against your most recent water bill will quickly show whether you have found the right number, since the number remains the same from one billing period to the next.

How a running meter can indicate a leak when no water is being used

If you have noticed an unusually high water bill or simply want to make sure that no water is escaping from a pipe out of sight, you can check directly at the meter with a no-flow test.

Quick test (15 to 30 minutes)

First, turn off all water-using appliances and fixtures: faucets, the washing machine, the dishwasher and any garden tap. Also avoid flushing any toilets during the entire test, since a running toilet is itself a common and easily overlooked reason why a meter never stops turning (source: APPRONO, How to detect a burst pipe). Note the meter reading, including the decimal places, and the position of the small, star-shaped indicator wheel. Then wait 15 to 30 minutes without using any water and check again: if the reading has changed or the star wheel is still turning, this indicates a leak somewhere in the pipes (source: APPRONO, How to detect a burst pipe).

Overnight test for very small leaks

A very small leak sometimes moves the star wheel so slowly that 30 minutes is not enough to detect it with certainty. In this case, note the reading in the evening and compare it the next morning before using any water for the first time; a flow this small can be measured more reliably over this longer period than in a short test (source: APPRONO, How to detect a burst pipe).

Manual reading versus continuous monitoring

A no-flow test only ever shows you the situation at the moment you carry it out. What happens between readings, such as a leak that starts over the weekend, inevitably goes unnoticed with this kind of spot check. If you would like to learn more about technical alternatives to manual reading, you can find an overview of smart water leak detectors and automatic shut-off valves.

The Smart Whole House Water Leak Detector with Auto Shut-Off Valve works differently from occasional meter reading: it is installed on the main water line and continuously measures flow using a built-in ultrasonic sensor with a sensitivity of up to 0.01 GPM (according to the manufacturer). If the device detects unusual flow, the motorized valve shuts off the water supply, and push, SMS and call notifications are sent through the associated app (according to the manufacturer). It is designed for standard 3/4-inch and 1-inch pipes, comes with the appropriate installation accessories, and the manufacturer recommends professional installation (according to the manufacturer).

A notification or automatic shutoff does not replace meter reading; it supplements it in the time between readings. No device can guarantee that it will prevent water damage, because no alarm can undo a drop of water that has already leaked. If you have confirmed a possible leak through the meter or an alarm, the next thing to know is where the main shut-off valve in your home is, so you can quickly turn off the water supply manually in an emergency.