Commercial water meter moving after hours? What to check
A meter still moving after the staff have left deserves a closer look. Start with what the site normally uses overnight, then record what remains unexplained.
Compare commercial water meter readings
Compare readings from similar operating periods. A busy production run, extra cleaning or irrigation can change consumption without a pipe fault. Check that the meter serial number matches the account and that you know which buildings it supplies.
Only read a meter that is safe to reach. Do not lift a heavy cover or enter a meter chamber. Ask your water retailer for help if access is unsafe or the reading is unclear.
Write down the reading, date and time. A photograph helps. For a small leak check, record the fractional digits or flow indicator as well as the whole cubic metres; follow the instructions for your meter model.
Account for automatic water use
A closed building is not always a building using no water. Ask the maintenance team about storage tanks refilling, water softener cycles, cleaning equipment, timed irrigation and processes that continue overnight.
- Look for a WC that continues to refill or trickles into the pan.
- Check accessible taps and visible connections for drips.
- Record any known automatic use during the observation period.
- Check whether other tenants share the metered supply.
Check water use when the building is closed
Choose a period when expected consumption is low and the site team can account for equipment still running. Take a reading at the start and another at the end, noting the elapsed time. A half-hour comparison can provide a useful starting record; intermittent leaks or very small losses may need longer monitoring. A moving meter shows water passing through it; it does not establish the cause or locate a leak. If automatic equipment is still drawing water, the readings are a consumption record rather than a conclusive leak test. An unchanged reading during a short check does not rule out an intermittent leak.
When the meter records cubic metres, a change of 0.010 m³ equals 10 litres. Record the actual figures for the engineer rather than estimating a yearly cost from one short test.
Leave isolation to the authorised site team
Commercial water systems can serve several units or critical equipment. Any isolation test needs someone who understands the pipework and can approve the interruption. Do not operate an unlabelled valve or interrupt a safety system as part of a meter check.
| Observation | Useful next step |
|---|---|
| Flow matches a known equipment cycle | Record the timing and expected demand, then check another quiet period. |
| Flow remains unexplained | Share the readings, site plan and known users with the leak survey team. |
| Flow changes during an authorised isolation test | Record which valve was operated and what it serves. Shared branches and passing valves can affect the result. |
Signs of an underground water supply leak
Persistent wet ground in a yard or low incoming pressure can accompany a buried supply leak, but these signs can have other causes. A dry surface does not rule one out. ADI uses acoustic listening, tracer gas and correlation to investigate commercial water mains and external pipework.
Information to send before a commercial leak survey
Include the postcode, building use, meter readings, the period measured and any obvious change in operations. Add available pipe drawings and photographs. Tell the office if the supply serves other units and who can arrange access to the meter and plant rooms.
Sources and further reading
This guide was checked on against Castle Water’s business leak-check guidance, Business Stream’s guidance on checking for leaks, and ADI Leak Detection’s published commercial survey information. Site systems and meter displays vary; ask your water retailer or survey team about your premises.
Still seeing unexplained use?
Call with the readings you have collected. The office can discuss the survey scope and current availability.