Camera water meter leak test: the leak rate in litres per hour in 30–120 seconds
The classic meter test means shutting everything off, waiting 30 minutes or more, then comparing two readings. Very often the answer is “it moved a little”, with no number that convinces the customer.
This guide explains the One-Minute Meter Leak Camera in Kashf Pro, a camera water meter leak test. Point the phone at the leak indicator or the smallest dial on the meter, and the tool tracks its rotation frame by frame and gives you the number of revolutions and the litres per hour and per day within 30, 60 or 120 seconds, with a report you can share by link.
What is a camera water meter leak test and what does it give you?
It is a tool inside the Kashf Pro app that uses the phone's rear camera. You place a yellow box over the rotating indicator on the meter, the tool reads that area about 15 times per second and calculates how far the indicator has turned.
While measuring it shows:
- A disc that turns with the indicator.
- The number of revolutions.
- The seconds elapsed.
- Litres per hour.
- The tracking quality.
At the end it gives a written verdict and a daily rate, with a button to save the result and a photo of the meter in a report.
Who is this tool for?
For leak detection technicians who want to prove a leak and measure its size in the first minutes of a visit, before bringing out listening or pressure equipment.
It also helps maintenance supervisors and property managers who check many meters and want a documented number for each unit.
When do you use it?
- At the start of a visit, to confirm a leak on the line between the meter and the tank, or on any part fed directly from the mains.
- After a repair, to prove the indicator has stopped and document it for the customer.
- When a customer complains about a high bill, to turn a suspicion into a figure in cubic metres per month.
For the simple home test aimed at customers, see the water meter test guide.
Where do you use it?
At a mechanical water meter with rotating dials, whether it sits in a meter room, in a box on the pavement or in the boundary wall of a villa.
The tool needs something that rotates: the star or triangle (the leak indicator), or the smallest rotating dial. Digital meters with no rotating indicator are not suitable; use the flow display on the meter itself instead.
What do you need before you start?
- A Kashf Pro account with a subscription, trial or credits, and camera permission in the browser.
- All outlets closed, with the tank full and its float valve shut. Alternatively, close the tank inlet valve to isolate the buried line.
- The litres per revolution of the indicator you will film. The smallest ×0.0001 dial turns once per litre, and a ×0.001 dial turns once per 10 litres. For the star, check the meter's manual or its faceplate.
- A cloth to wipe the meter glass, shade if the sun shines directly on it, and a steady hand or a stand.
How to use it correctly, step by step
One-Minute Meter Leak CameraSubscription — free trial available
The tool crops the area inside the yellow box to a 64×64 greyscale image. It then calculates angular moments in a ring around the centre, between 12% and 95% of the radius.
On the first frame it detects the order of symmetry, meaning how many times the indicator's shape repeats in one turn, from 1 to 8. A single pointer has order 1, for example, and a six-armed star has order 6. After that it follows the shape's angle roughly every 66 milliseconds and adds up the unwrapped angle differences, so no revolution is lost when it passes 360°.
The formulas:
- Revolutions = total angle ÷ 360°.
- Litres per hour = revolutions × litres per revolution ÷ time in hours.
- Litres per day = litres per hour × 24.
The preset indicator options are:
- “Smallest dial on the meter ×0.0001 (1 revolution = 1 litre)”.
- “Smallest dial on the meter ×0.001 (1 revolution = 10 litres)”.
- “Star / triangle indicator”, where you enter the litres per revolution yourself.
Steps for correct use
- Isolate the line before filming
Close every tap, appliance valve, water heater and irrigation valve. Then make sure the roof or ground tank is full and the float valve is not letting water in. If you only want to test the buried line, close the tank inlet valve. Without this step the tool will measure the tank filling up as if it were a leak.
- Open the camera and the light
Tap 📷 Open camera and allow access; the rear camera opens. Wipe the meter glass. If it is dark, tap 🔦 Light; this button only works on phones that allow the browser to control the flash. Move the phone closer until the indicator fills a clear part of the picture.
- Choose the indicator and place the box
Under Indicator being filmed choose the smallest ×0.0001 dial if there is one, because it is the most precise. If you choose the star, enter the value from the meter's manual under Litres per revolution, for example 0.1. Drag the yellow box until its centre sits on the axis of rotation, and drag its corner to enlarge it until it surrounds the indicator without many digits around it.
- Choose the duration and steady the phone
Choose the Measurement duration: 30 seconds for an obvious leak, 60 seconds as the default and 120 seconds for a slow leak. Rest the phone on the edge of the box or on a stand, then tap ▶ Start measurement. This is when a session is counted against your plan, and the message “Do not move the phone” appears.
- Watch the tracking quality
While measuring, watch the Tracking quality field, which shows “Excellent”, “Good” or “Weak”. If it stays “Weak”, stop the phone shaking, move the camera closer and remove reflections by tilting the phone slightly. Litres per hour start to appear after 3 seconds.
- Read the verdict and save
When the time is up, the verdict appears below the disc. If tracking was acceptable, tap 💾 Save result to store a camera photo with the numbers in a report you can share by link. If tracking was very weak, the save button stays disabled, so measure again.
How to read the result
“No noticeable indicator movement — no flow above about … L/h after the meter (provided all outlets are closed)”: shown when the calculated flow is below the smallest flow the chosen indicator and duration can detect. That threshold in L/h = 0.03 revolutions × litres per revolution ÷ measurement time, and the tool shows it under the settings before you start (“Smallest detectable flow…”) and in the result text.
Examples of the threshold:
- On the one-litre dial over 60 seconds: about 1.8 L/h.
- Over 120 seconds: about 0.9 L/h.
- On the 10-litre dial over 60 seconds: about 18 L/h, which is not a small leak.
If the threshold is above 2 L/h, the tool warns you that the indicator is too coarse to reveal small leaks. So if you get “no movement” on a coarse indicator, measure again on the smallest dial or over 120 seconds.
“Indicator rotating — confirmed flow of … L/h ≈ … L/day”: water is passing through the meter, and the tool reminds you that this is a leak after the meter only if every outlet was closed and the tank or float supply, evaporative cooler and irrigation were isolated. Do not count it as a leak until you are sure the float is not filling the tank and no appliance is drawing water. Then move on to isolation: close the tank valve and measure again. If the indicator stops, the leak is after the valve; if it keeps turning, it is on the buried line between the meter and the valve.
“Weak tracking — move the camera closer, place the box exactly on the indicator and measure again”: the result is rejected and cannot be saved.
The moving disc shows the accumulated rotation, so you can compare it by eye with the real indicator.
A worked example: from revolutions to cubic metres
You closed every outlet, the tank is full, and you filmed the smallest ×0.0001 dial for 60 seconds. The tool reported 0.85 revolutions.
- Litres = 0.85 × 1 litre = 0.85 litres per minute.
- Litres per hour = 0.85 × 60 = 51 L/h.
- Litres per day = 51 × 24 = 1,224 L/day, or about 1.2 m³ a day.
- Per month: about 36.7 m³, which can push a bill into higher bands on a tiered tariff.
To estimate the effect on the bill, see the leak waste and cost guide. The final reference is always the official bill from the water utility (in Saudi Arabia, the National Water Company).
After the repair, measure again with the same indicator and duration and save both results. A before-and-after pair of reports convinces a customer more than any explanation.
Meters and tanks in Saudi homes: what does the test cover?
The usual layout in Saudi Arabia is: the public network, then the meter, then a buried line to a ground or roof tank, then a booster pump, then the household pipework. Many homes in other hot, water-scarce regions follow a similar pattern.
The meter test only covers what comes before the tank, meaning the buried line, any point fed directly from the mains, and the tank's own float valve if it does not seal. Leaks after the pump do not move the meter directly. They drain the tank, and the float then opens to refill it. That is why the meter may turn intermittently even though the leak is inside the house.
To tell the two cases apart:
- Close the tank inlet valve and measure. If the indicator turns, the leak is on the buried line before the valve.
- Open the valve and watch the tank level with all use stopped for long enough. A falling level means a leak after the tank.
Some areas have smart meters with no rotating indicator, and this tool does not suit them.
Common mistakes that spoil the result
- Counting tank refilling as a leak: the most common mistake. Make sure the float is closed, or isolate with the tank valve.
- Choosing a coarse indicator: the 10-litre dial will not show a small leak in 30 seconds. Start with the smallest dial.
- A wrong litres-per-revolution value for the star: every figure scales with it. Take it from the meter's manual, not from a guess.
- An off-centre box: if the centre of the box is not on the axis of rotation, tracking weakens and revolutions can be lost.
- Hand movement and reflections: shaking and sunlight glinting on the glass weaken tracking. Rest the phone on something solid and use shade.
- A very fast indicator: if the star spins faster than your eye can follow, the tool may lag behind it. The leak is already large, so measure on a slower dial.
The honest limits of the tool
- The result is an estimate that depends on the correct litres per revolution, a steady phone and a good image. In tests on simulated video the error was roughly ±12%, and field performance can differ.
- The “no movement” threshold is calculated in L/h from the litres per revolution and the duration (based on 0.03 revolutions), so its sensitivity varies with the indicator and the duration, as in the examples above.
- The tool cannot tell whether the water passing through is a leak or legitimate use. That is the job of correct isolation before measuring.
- It does not work on digital meters with no rotating indicator, or through cloudy or cracked glass.
- It proves that a leak exists and how big it is in the part of the network you isolated; it does not find where it is. For location you need listening, thermal imaging or tracer gas.
- The result supports your judgement and does not replace it.
When to escalate or ask for a second opinion
- The meter proves a leak on the buried line between the meter and the tank, and the line is long or runs under a tiled yard or driveway. Tracer gas or a two-sensor correlator helps here.
- A large rate, or water appearing near foundations or a boundary wall. A licensed structural engineer may be needed to assess the soil and foundations.
- The customer needs a documented technical report to dispute the bill with the water utility.
- Water near an electrical panel or a pump: switch off the power first.
You can ask the Kashf team, which works in Saudi Arabia, for a second opinion or subcontract them. The team detects leaks electronically without breaking, using acoustic and thermal equipment, pressure testing and tracer gas, and hands over a written report that can be checked on the verification page. Book from the order page or on WhatsApp at +966544027180.
Frequently asked questions
Is a camera water meter leak test as accurate as waiting half an hour?
It gives you a number faster and documents it with a photo, and its accuracy depends on the correct litres per revolution and steady filming. For a very slow leak, measure on the smallest dial for 120 seconds, and if doubt remains, compare it with two meter readings taken some time apart. The two methods complement each other.
How do I know how many litres one revolution represents?
The smallest dial marked ×0.0001 completes one revolution per litre, and the one marked ×0.001 completes one revolution per 10 litres. The star or triangle varies by manufacturer, so take the value from the meter's manual or faceplate. If you cannot find it, film the smallest dial instead.
Why does the tool report confirmed flow when the house has no leak?
Usually because the tank is filling or an appliance is drawing water, such as an evaporative cooler, automatic irrigation or a water purifier. The tool only measures water passing through. Close the tank inlet valve and measure again: if the indicator stops, the flow was refilling or inside the house; if it continues, the buried line is leaking.
Does the tool work with a smart meter?
It needs a mechanical indicator that rotates. If the meter is digital with only a display, there is nothing for the camera to track, so use the flow or consumption reading shown on the meter itself, or compare two readings taken over a period.
What measurement duration should I choose?
Sixty seconds suits most cases. Use 30 seconds for an obvious leak where you can see the indicator turning, and 120 seconds for a slow leak. A longer duration raises sensitivity, because the “no movement” threshold in L/h gets smaller as the time grows, and the tool shows it before you start.
What does weak tracking quality mean?
It means the tool cannot see a clear rotating pattern inside the box, because of shaking, reflections, an off-centre box or a distant image. Steady the phone, move the camera closer, tilt it to remove glare and turn on the light if it is dark. If tracking stays very weak, the result is rejected and cannot be saved.
Does the test show where the leak is?
No. It proves that water is flowing and at what rate in the part you isolated. By closing valves one at a time you learn which section is leaking, then you pinpoint the location by listening, thermal imaging or tracer gas.
Is every measurement deducted from my plan?
Usage is counted per session. A session starts with your first measurement and stays valid for a set time during which you can measure again without another deduction. Some plans make the tool unlimited, and when the limit runs out you can upgrade or buy credits on the website.
How do I document the result for the customer?
Tap save after measuring and you get a report link showing the revolutions, the duration, the litres per hour and per day, the tracking quality and a photo of the meter. Send it to the customer on WhatsApp, and save a second measurement after the repair for comparison.
This guide is educational. It explains estimation tools that help you understand a situation and decide what to do next; confirming a leak and pinpointing it always requires an on-site inspection with instruments. Structural questions are for a licensed engineer to decide.