To read your water meter, note the black digits, which show whole cubic metres used (one cubic metre is 1,000 litres). The red digits are decimals you can ignore for your bill. To check for a leak, turn off all water and watch the meter: if it keeps moving, or the reading climbs overnight with nothing running, water is escaping somewhere.
Your water meter is the cheapest leak detector you own. It quietly counts every litre that passes into your home, which makes it the one tool that can prove a hidden leak before you ever see a damp patch. The trouble is that most people have never been shown how to read it, or how to use it to tell whether water is escaping. This guide covers both: how to find and read your meter, digital or dial, and the simple overnight test that turns it into a leak check.
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Where to find your water meter
Most UK homes have the meter in one of two places. Outside, it usually sits under a small round or rectangular cover in the path, driveway or footpath near your boundary. Lift the cover with the edge of a screwdriver and remove any polystyrene frost plug to see the face. CCW advises against trying to lift a heavy metal pavement cover yourself, so if it will not move easily, leave it. Indoors, the meter is often where the supply pipe enters the house: under the kitchen sink, in a downstairs cupboard, the garage or near the internal stop tap. If you cannot find it at all, your water company can tell you where it was fitted.
How to read your water meter
Reading the meter is simpler than it looks once you know which numbers count. The display records a running total of all the water used since the meter was installed, in cubic metres. You read it left to right.
- Black digits: whole cubic metres. This is the figure your water company bills from, so it is the only number you submit.
- Red digits or red dials: tenths and hundredths of a cubic metre, in other words litres. You ignore these for your bill, but they matter for the leak test below because they move first.
WaterSafe sums it up plainly: focus on the black numbers, which show cubic metres used, and leave the red ones alone when you send a reading. To submit a reading, write down the black digits and pass them to your supplier online, by phone or by post. CCW suggests reading the meter at least once every three months so your bills track real use rather than estimates.
Digital meters and dial meters
There are two common styles, and they are read slightly differently.
Digital meters
A digital meter shows the figure on an LCD screen, which makes it the easier of the two. The numbers before the decimal point are whole cubic metres, and the numbers after it are litres. Record only the figures before the decimal point. Some screens cycle through a few displays, so wait for the one showing the main cubic-metre reading. Many also have a tiny flow indicator, a star, triangle or dot that flickers whenever water is passing through, which is the part you will use for the leak test.
Dial and odometer meters
Older mechanical meters show the reading on a row of rotating numbers like a car odometer, sometimes with separate clock-style dials beneath. Read the black or white digits across the top for whole cubic metres, then ignore the red dials, which count fractions. As CCW describes it, the black-on-white figures are cubic metres and tens of cubic metres, while the red dials are the decimal places. Those red dials are useful for spotting a leak, because even a slow escape will keep the smallest red dial turning.
What a cubic metre means on your bill
Your meter and your bill both work in cubic metres, so it helps to picture what one is. A cubic metre is 1,000 litres of water. Severn Trent describes a cubic metre as roughly what a typical household uses in five to seven days, which gives you a feel for the scale. That context is what makes the meter such a good leak detector. If your reading jumps by a cubic metre or two overnight, with no one in the house using water, that is hundreds of litres going somewhere it should not, and it is the kind of loss a hidden leak produces.
How to check your water meter for a leak
This is where the meter earns its keep. The test costs nothing and takes a few minutes of setup plus a wait. Water companies and CCW recommend the same basic method.
- Turn everything off. Close every tap, and make sure no appliances are drawing water: no washing machine, dishwasher, ice maker, water softener or garden irrigation running. Anyone in the house needs to leave the water alone for the test.
- Watch the flow indicator. Look at the digital flow marker or the smallest red dial. With all water off, it should be completely still. If it keeps ticking round, water is moving through the meter, which means a leak.
- Run the overnight version for certainty. A spinning dial is obvious, but a slow leak can be hard to see in real time. So note the full meter reading last thing at night, use no water overnight, then read it again first thing. CCW suggests the same check across a day if that suits you better: take a reading, use no water, and read it again when you return. If the number has risen, water escaped while nothing was being used.
A still meter and an unchanged overnight reading are a good sign that your plumbing is sound. Movement at rest, or a reading that climbs with nothing running, tells you to look closer.
Is the leak inside or on the supply pipe?
If the test shows water moving, the next step narrows down where. Find your internal stop tap, usually under the kitchen sink, and turn it off. Then watch the meter again.
| What the meter does | What it means |
|---|---|
| ✔ Meter stops once the internal stop tap is closed | The leak is somewhere inside the house, on your internal pipework or fittings |
| ✘ Meter keeps moving with the internal stop tap closed | The leak is on the underground supply pipe, between the meter and your home |
This matters because of who pays. CCW confirms that a leak on your private supply pipe, the section running from the meter to your property, is normally the homeowner's responsibility to find and repair, not the water company's. A supply-pipe leak often shows up as a meter that will not settle even with the whole house isolated, and frequently with no sign at the surface at all. If you have already had a high bill with nothing visible, our guide on a surprisingly high water bill with no obvious leak covers the wider picture, and if you are not sure where your stop tap is, here is how to find and use your water shut-off valve.
When the meter says leak but you can't see one
The meter test is brilliant at proving a leak exists. It is far less good at telling you where the water is going. Once the meter shows movement with everything off, and especially when the supply-pipe check points underground, the leak is hidden, and chasing it by lifting floors or digging at random tends to cause more damage than it solves.
That is the point to bring in proper equipment. We trace hidden leaks across Cornwall and Devon with non-invasive professional water leak detection: thermal imaging, acoustic sensors and tracer gas pinpoint the exact spot before anything is opened up. Your meter has already done the hard part of confirming there is a leak. The job from there is finding it precisely, with the least disruption to your home, and getting it documented if you need to claim on your insurance.
Frequently asked questions
How do I read my water meter?
Read the black digits from left to right. They show whole cubic metres of water used since the meter was fitted, and that is the figure your water company bills from. The red digits, or red dials, record tenths and hundredths of a cubic metre, so you ignore those for your bill.
What is a cubic metre of water?
A cubic metre is 1,000 litres of water, and it is the unit your meter and your bill use. Severn Trent puts it at roughly the amount a typical household gets through in five to seven days, so a single extra cubic metre showing overnight is a sign that something is running when it should not be.
How do I check my water meter for a leak?
Turn off every tap and water-using appliance, then look at the meter. If the flow indicator or the red dial keeps turning with everything off, water is escaping somewhere. For a clearer result, note the reading at night, use no water, then read it again in the morning. Any rise points to a leak.
Should my water meter move when no water is running?
No. With all taps and appliances off, the flow indicator and the meter reading should stay completely still. CCW notes that a dial still spinning with everything off usually means a leak, so movement at rest is your cue to investigate rather than ignore.
Is the leak inside my house or on the supply pipe?
Turn off your internal stop tap, usually under the kitchen sink, then watch the meter. If it stops, the leak is inside the house. If it keeps moving, the leak is on the supply pipe between the meter and your home, which is normally your responsibility to repair as the property owner.
What does a smart water meter show?
A smart meter sends readings to your water company automatically and often flags continuous overnight flow, which is a classic leak signature. You still read the display the same way, in cubic metres, but the usage history in your online account can confirm a leak without an overnight test.
Meter moving with everything off? We'll find the leak
If your meter proves there's a leak but you can't see where, we trace it across Cornwall & Devon with non-invasive equipment, then document it for your insurer. Fast response, minimal damage.
Call Dickie on 07822 025 911 No Find, No Fee on residential leak detection (subject to terms)