The short answer
If your water meter keeps moving with every tap, appliance and toilet turned off, you almost certainly have a leak. Turn off your internal stop tap: if the meter stops, the leak is inside your home; if it keeps going, the leak is on your outside supply pipe.
A water meter that ticks over when you have switched everything off is one of the clearest warning signs of a hidden leak. Water meters only register flow when water is actually moving through the pipe. So if nothing in the house is running and the dial is still creeping round, water is escaping somewhere it shouldn’t be.
The good news is that you can do a fair amount of detective work yourself before you call anyone out. With a torch, a notepad and ten quiet minutes, you can confirm whether there really is a leak and narrow down roughly where it sits. That tells you who is likely responsible for the repair and what your sensible next step is.
First, confirm the meter is really moving
Your meter is usually in an outdoor boundary box near the pavement, or sometimes in a cupboard or under the stairs. Lift the lid, wipe the face clean and have a proper look. Most modern meters have a small red or black spinning dial, a star-shaped wheel, or a tiny flow indicator that turns at the faintest trickle. That sensitive dial is your friend here, because it picks up leaks far too small to hear.
Before you test, make sure nothing in the property is genuinely using water. Turn off every tap. Check that no toilet is refilling, the washing machine and dishwasher are off, the garden hose is disconnected, and any water softener or irrigation timer is not mid-cycle. A garden tap left dribbling or a slowly refilling cistern can easily look like a leak when it is just normal use.
Now watch the dial. The cleanest way to be sure is to take a reading, write it down, then leave the house untouched for an hour or two and read it again. If the numbers have moved with everything off, water is being lost somewhere on the system.
Use the stop tap to find out where the leak is
This is the test that does the real work. Your internal stop tap (sometimes called the stopcock) is the valve that shuts off water to the whole house. It is most often under the kitchen sink, but it can also live in a downstairs cloakroom, a utility room, the garage or near the front door. Turning it clockwise shuts the supply to everything beyond it inside your home.
With the meter still showing movement, fully close the internal stop tap, wait around thirty seconds for the pipes to settle, then go back and watch the meter dial again. What happens next tells you which side of the stop tap the problem is on.
What the result tells you:
- Meter STOPS when the stop tap is closed: the leak is inside your home, on the pipework or fittings after the stop tap. Think under floors, in airing cupboards, behind walls, or a slowly leaking toilet, cylinder or appliance.
- Meter KEEPS MOVING with the stop tap closed: the leak is on your outside supply pipe, the underground run between the meter and your house. This is the buried section that often springs leaks at joints or where pipes have aged.
- Meter does not move at all once everything is off: there is probably no continuous leak. A high bill may instead come from intermittent use such as a sticking toilet valve, so keep an eye on it over a few days.
Why supply pipe versus internal matters
Knowing which side of the stop tap the leak sits on is not just useful for finding it. In England, it usually decides who is responsible for the repair. As a rule of thumb, your water company looks after the water main in the road and the communication pipe up to your boundary. The supply pipe that runs from the boundary into your home, plus all the pipework inside, is generally the property owner’s responsibility.
In Devon your supplier is typically South West Water. Many water companies offer help with a first supply pipe leak, which can include a contribution towards repair or replacement costs and a short period of free leak location. Metered customers may also be able to claim a leakage allowance that credits the bill for water lost, once the leak has been fixed. The exact terms, time limits and any need for a qualified plumber’s receipt vary, so it is always worth checking the current policy directly with South West Water before you commit to work.
What to do next
If your test points to an internal leak, start with the obvious culprits. Dye tablets or a few drops of food colouring in the toilet cistern will reveal a silent flush within ten minutes if the colour creeps into the bowl without flushing. Check under sinks, around the boiler and hot water cylinder, and look for damp patches, lifting flooring, a warm spot on a floor, or a musty smell. A visible leak under a sink is often something a competent plumber can sort quickly.
If the test points to the supply pipe, the leak is underground and rarely shows on the surface. Digging up the garden or driveway hoping to find it is expensive and often misses the mark. This is exactly where non-invasive water leak detection earns its keep, using acoustic listening equipment, tracer gas and thermal imaging to pinpoint the spot before anyone lifts a slab. You can read more across our articles, and our wider work across Devon is covered on the site.
In the meantime, keep noting your meter readings. A clear before-and-after record helps your supplier, helps any plumber you bring in, and supports a leakage allowance claim later. And if you ever need to limit damage quickly, closing the internal stop tap stops water reaching the house while you decide what to do.
Frequently Asked Questions
Take a reading with everything off, then leave the house untouched for at least one to two hours and read it again. A short watch can miss a slow leak, so the longer gap gives a clearer result. If the numbers have moved at all with no water in use, treat it as a likely leak.
It is most commonly under the kitchen sink, but it may also be in a downstairs cloakroom, utility room, garage, or near the front door where the main enters the property. Turn it clockwise to close. If you cannot find it or it is stiff, a plumber can locate and free it safely.
In most cases yes. If water still flows once the internal stop tap is fully closed, the loss is on the underground supply pipe between the meter and your home. These leaks are often invisible at the surface, which is why specialist detection is the practical way to find the exact point.
It depends on where the leak is and their current policy. The company typically covers the main and communication pipe up to your boundary, while the supply pipe and internal pipework are usually yours. Many suppliers help with a first supply pipe leak, so check the latest terms directly with South West Water.
Yes. A continuous trickle that barely moves the dial still runs every hour of every day, which adds up on a metered bill and can soften ground or damage foundations over time. Finding and fixing it promptly is usually far cheaper than leaving it to worsen.
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