To check your water meter for a leak, turn off every tap and water-using appliance so nothing is drawing water, then read the meter. Wait at least two hours, or overnight, using no water, and read it again. If the figure or the leak indicator dial has moved, you have a leak. Isolating the stop tap and re-testing then shows whether it is inside or outside.
A high bill, a damp patch you cannot explain, or a notice from South West Water saying your usage has jumped can all leave you wondering whether water is escaping out of sight. Your water meter is the simplest tool for settling the question. It measures every drop that enters the property, so if it keeps ticking over while you use nothing, water is going somewhere it should not. This guide covers the meter test step by step, where to find your meter, what the leak indicator dial does, and how to tell whether the leak sits inside or outside.
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Where to find your water meter
Before you can test it, you need to find it. The meter is usually in one of two places, and which one depends on how your supply was installed.
- Outside, in a boundary box. Most commonly the meter sits in a boundary box near the edge of your property, in the front garden, the drive or the footpath. Look for a small round or rectangular cover set into the ground; you may need to lift the outer lid to see the meter underneath.
- Inside the property. In some homes the meter is fitted indoors, close to the internal stop tap. That is usually under the kitchen sink, but it can also be in a downstairs toilet or a garage. WaterSafe, the official register of approved plumbers, notes this is where many internal meters and stop taps live.
If you genuinely cannot find your meter, your water company can tell you where it was fitted. For a closer look at reading the dials once you have located it, see our guide on how to read a water meter.
The water meter leak test, step by step
This is the test the water companies themselves recommend, and it costs nothing but a little patience. The idea is simple: if the meter records water passing through while you are using none, that water is leaking. Work through it in order.
- Turn everything off. Close every tap inside and out, and switch off anything that draws water automatically: the washing machine, dishwasher, ice maker, water softener and any garden irrigation. Nobody should use water during the test, so it helps to run it overnight or while the house is empty.
- Wait about half an hour first. Toilet cisterns and storage tanks need time to finish refilling after their last use. Waiting roughly 30 minutes before the first reading stops a normal refill being mistaken for a leak.
- Take your first reading. Write down the full reading, and note the small red digits. Those measure the smaller volumes, in litres, and they are where a slow leak first shows up.
- Leave it, using no water. Wait at least two hours, or leave it overnight. The longer the gap with no water use, the clearer the result, which is why an overnight test is the most reliable.
- Take your second reading. Read the meter again, red digits included. If it is exactly the same, you almost certainly have no leak. If it has crept up at all when no water was used, water is escaping somewhere on your system.
One quick sense check: make sure a toilet was not silently refilling and no outside tap was dripping, because both move the meter and look exactly like a hidden leak.
Reading the leak indicator dial
Many meters give you an even faster check than two readings hours apart. Look on the face of the meter for a small flow indicator. On a mechanical meter it is often a little spinning triangle, star or wheel; on a digital meter it may be a droplet symbol or flow icon on the display. Whatever the shape, it moves whenever water passes through the meter.
With every tap and appliance off, watch the indicator for a minute or two. If it sits completely still, no water is flowing and you are clear. If it creeps round, flickers or keeps spinning while you use none, that points straight to a leak. A fast spin suggests a larger leak; a slow crawl a small or intermittent one. The indicator will not tell you where the leak is, only that water is escaping, but it confirms the problem in minutes rather than hours.
Inside or outside: narrowing it down at the stop tap
Once the test or the indicator has confirmed a leak, the next question is where. One more step narrows it down a long way, using your internal stop tap, sometimes called the stopcock. This is the valve that shuts off the water to your whole property, usually under the kitchen sink.
Turn the stop tap off clockwise. Do it slowly and do not force it, especially on an older tap. With the supply to the house now isolated, check the meter or its leak indicator again.
| What the meter does | What it means |
|---|---|
| The meter still moves with the stop tap off | The leak is on the supply pipe between the meter and your stop tap. That section is often outside and underground. Much of it can be your water company's responsibility, so contact South West Water before you do anything else. |
| The meter stops once the stop tap is off | The leak is inside the property, on the pipework after the stop tap. That is the homeowner's responsibility to locate and repair. This is where hidden leaks under floors, in walls or beneath a slab tend to hide. |
This single step saves a lot of wasted effort. It tells you whether to pick up the phone to your supplier or to start tracing a leak inside your own home. If you have already had a letter from the supplier, our guide on what to do when South West Water says you have a leak walks through the next moves.
What to do if the meter confirms a leak
A moving meter tells you water is escaping, but it rarely tells you where from. Plenty of leaks never show as a puddle or a stain, because the water soaks away into the ground, runs along a pipe under the floor or tracks inside a wall cavity. That is exactly the situation behind a high water bill with no visible leak: the meter proves the loss, but there is nothing obvious to see.
At that point, lifting floors or knocking through walls to chase it is a gamble. Professional leak detection takes the guesswork out. A specialist pinpoints the source without digging up the house, using several non-invasive methods together:
- Acoustic detection picks up the sound a pressurised pipe makes as water escapes, which locates buried mains and underground leaks.
- Thermal imaging reads the temperature differences a leak creates, mapping a hot heating leak or a cold supply leak back towards its source.
- Tracer gas is introduced into the pipework and rises to the surface at the precise point it is escaping, catching small or slow leaks that nothing else finds.
- Moisture meters confirm how far the dampness has spread and where it is wettest, narrowing the search.
Together these turn a confirmed-but-invisible leak into a single marked spot, so any repair is targeted rather than exploratory. Our water leak detection service explains how we work across Cornwall and Devon. Many home policies also include trace and access cover, which pays to find a hidden leak and make good the damage caused by reaching it, with limits that typically start around five thousand pounds. Cover varies, so check yours, and keep the meter readings and any photographs as evidence.
Frequently asked questions
How do I check my water meter for a leak?
Turn off every tap and water-using appliance so nothing is drawing water. Wait about half an hour for any tanks and cisterns to refill, then write down the meter reading, including the small red digits. Leave it for at least two hours, or overnight, using no water. Read it again. If the figure has moved, you have a leak.
Why is my water meter still moving when everything is off?
If the meter or its leak indicator keeps moving while every tap and appliance is off, water is escaping somewhere on your supply. A running toilet or a dripping outside tap can cause it, but so can a hidden pipe leak under a floor or in the ground. Isolating the internal stop tap and re-testing tells you whether it is inside or outside.
What is the leak indicator on a water meter?
Many meters have a small flow indicator, often a spinning triangle or star on a mechanical meter, or a droplet symbol on a digital one. It turns whenever any water passes through the meter. If it moves while you are using no water at all, that points to a leak rather than normal use.
How do I tell if the leak is inside or outside my home?
Turn off your internal stop tap, then check the meter again. If the meter still moves, the leak is on the supply pipe between the meter and the stop tap, often outside, and you should contact your water company. If the meter stops, the leak is inside the property after the stop tap, which is the homeowner's responsibility to find and repair.
Where is my water meter?
Inside, the meter is usually near the internal stop tap, commonly under the kitchen sink, in a downstairs toilet or in a garage. Outside, it is normally in a boundary box near the edge of the property, in the front garden, drive or footpath, under a small round or rectangular cover you may need to lift.
The meter test shows a leak but I cannot see any water. What now?
Many leaks are hidden under floors, in walls or buried in the ground, so a confirmed meter test often shows no visible water at all. That is the point to call for professional leak detection, which uses thermal imaging, acoustic listening and tracer gas to pinpoint the source without digging up the whole house.
Meter moving but no leak in sight? We will find it
If your meter test confirms a leak you cannot see, we trace it across Cornwall and Devon with acoustic detection, thermal imaging and tracer gas, so we pinpoint the source without tearing up floors or walls. Fast response, minimal damage, and the insurer-ready report if you need to claim.
Call Dickie on 07822 025 911 No Find, No Fee on residential leak detection (subject to terms)