If your water meter is spinning with nothing on, water is passing through somewhere on your supply. Turn off your internal stopcock: if the meter stops, the leak is inside; if it keeps moving, it’s most likely in the underground pipe. A small, slow-moving low-flow dial is a genuine sign of a leak, worth acting on.
A water meter that keeps ticking over when every tap is off and nothing is running is one of the clearest signals that something is wrong, but it doesn’t tell you where. This guide walks through how to isolate internal plumbing from the supply pipe, what to make of a barely-moving dial, and what South West Water customers specifically need to know about responsibility and support.
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Confirming the meter really is moving
Before drawing any conclusions, it’s worth confirming the test properly. Turn off every tap and appliance in the house, make sure nothing is mid-cycle, and give any toilet cistern time to settle after its last flush. Note the exact reading, including the smallest dial, wait 15 to 30 minutes without using any water, and check again. If the reading has changed at all, water is moving through the meter with nothing intentionally using it. Our guide to checking your water meter for a leak covers this test in more detail, and our guide on how to read a water meter explains what the different dials and digits mean if you’re not familiar with your specific meter.
Isolating internal plumbing from the supply pipe
Once you’ve confirmed the meter is moving, the next useful step is working out roughly which side of the property boundary the leak sits on, since that affects who is responsible and how it gets fixed.
- Locate your internal stopcock, usually under the kitchen sink or in a downstairs cupboard near where the supply enters the house.
- With the meter reading noted, turn off the internal stopcock, which stops water flowing into your household plumbing but leaves the underground pipe between the meter and the stopcock still under pressure.
- Wait 15 to 30 minutes, then check the meter again.
| Result with stopcock off | What it means |
|---|---|
| Meter stops moving | The leak is inside the house, in pipework, a cistern, or an appliance connection past the stopcock |
| Meter keeps moving | The leak is most likely in the underground supply pipe between the meter and the stopcock |
This simple test doesn’t pinpoint the exact leak, but it narrows the search area considerably and helps decide who needs to be involved next.
What a small, slow-moving dial actually means
Many meters include a small triangular, star-shaped or spinner low-flow indicator, separate from the main digit readout, designed specifically to catch very small, continuous flows. It’s easy to dismiss a barely-turning dial as insignificant, but that indicator is often the earliest and clearest evidence of a slow leak, precisely because it’s built to detect flows too small to move the main dial noticeably over a short test.
Whose responsibility is the leak
South West Water is responsible for the mains supply up to the boundary or property stop tap, while the homeowner is responsible for the private supply pipe running from that point into the house. This matters for a spinning meter because the meter itself usually sits at or near the boundary, so a leak detected there could sit on either side of that responsibility line, which is exactly what the internal stopcock test above helps establish.
South West Water and the leak allowance scheme
South West Water runs a leak allowance scheme for metered customers, though conditions apply and evidence that the leak has been repaired is usually required. If a constantly spinning meter has already pushed up your bill, it’s worth contacting South West Water once the leak is confirmed and fixed, rather than assuming the higher charge is simply something to absorb. For the full detail on eligibility and how the scheme works, it’s best to check directly with South West Water or our dedicated guides on their policies, since the specific terms can change.
How the leak is actually found
Once the isolation test points to internal plumbing or the supply pipe, the next step is finding the exact location without unnecessary digging or opening up. Our mains water leak detection service uses acoustic correlators to listen for the sound signature of water escaping a pressurised pipe at two accessible points, then calculates the leak’s position from the timing difference between them. Where the ground conditions or pipe material make the acoustic signal weaker, tracer gas, a safe mix of 5% hydrogen and 95% nitrogen, can be introduced into the pipe and picked up at the surface with a sensitive probe.
For leaks confirmed inside the house, our wider water leak detection service combines the same acoustic methods with thermal imaging and calibrated moisture meters to trace the source through walls, floors and voids.
Supply pipes in Cornwall and Devon
Rural properties across Cornwall and Devon often have long private supply runs from the boundary to the house, sometimes crossing fields, driveways or gardens with mature trees whose roots can stress ageing pipework over time. Older granite cottages and farmhouses can also have supply pipes routed decades ago with little documentation, which makes an accurate isolation test even more valuable before any digging starts. We see this pattern regularly on rural properties: a spinning meter with the stopcock test pointing to the supply side, followed by an acoustic survey that narrows a long run down to a few metres worth investigating.
Frequently asked questions
Why is my water meter still moving when every tap is off?
If every tap and appliance is off, nothing is due to refill, and the meter still moves, water is passing through your supply somewhere. That usually means a leak, either in the underground supply pipe running to the house, in internal pipework, or occasionally a fault with a cistern or valve that hasn’t fully closed.
How do I isolate whether the leak is inside my house or on the supply pipe?
Turn off your internal stopcock, which controls water entering the house, while leaving the section of pipe between the meter and the stopcock live. If the meter stops moving with the internal stopcock off, the leak is inside the house. If it keeps moving, the leak is most likely in the underground pipe between the meter and the stopcock.
Does a small, slow-moving dial still mean a leak?
Yes, small dial movements matter. Many meters have a small triangular or star-shaped low-flow indicator that turns even with a very small trickle, so a barely-moving dial with everything off is often the first visible sign of a slow leak rather than something to dismiss.
Who is responsible for a leak on the supply pipe to my house?
South West Water is generally responsible for the mains pipe up to the boundary or property stop tap, while the homeowner is responsible for the private supply pipe running from that point into the house. If the leak is on your side of the boundary, it is usually your responsibility to arrange repair.
Can I get help with my bill if the leak is on my supply pipe?
South West Water runs a leak allowance scheme for metered customers, though conditions apply and evidence of repair is usually needed. It’s worth contacting them directly once the leak is confirmed and fixed, rather than assuming a higher bill is unavoidable.
How much water can a constantly moving meter actually waste?
It depends entirely on the size of the leak, but the Association of British Insurers notes that escape of water costs UK insurers roughly £1.8 million a day in payouts, which reflects how much damage even modest, ongoing leaks can cause over time. A meter that never stops moving is a sign the volume keeps adding up around the clock, well beyond normal usage.
How is a leak on an underground supply pipe found without digging up the whole garden?
Acoustic correlators can listen for the sound of water escaping a pressurised pipe at two accessible points, such as the meter chamber and the stopcock, and calculate the leak’s position from the timing difference. This usually narrows excavation down to a specific, small section of pipe rather than the full run.
Meter won’t stop moving? Let’s find out where it’s going
If your isolation test points to a leak but you can’t see where it is, we’ll trace it across Cornwall & Devon with non-invasive equipment, on the supply pipe or inside the house.
Call Dickie on 07822 025 911 No Find, No Fee on residential leak detection (subject to terms)