Checking for problems with your supply's flow, pressure and velocity
How to check for issues with your water supply, test your water pressure, and what to do if you think you have a problem
The difference between flow, pressure and velocity
If water isn't coming out of your taps as quickly or as powerfully as normal, you may have a problem with the flow, pressure or velocity of your water.
Often it's hard to know what the difference is between the three terms.
- Flow: The amount of water coming out of your tap
- Pressure: The force of the water coming out of your tap
- Velocity: The speed of the water coming out of your tap
If you have a problem with your water pressure, it will probably affect all your taps.
If you have a problem with flow or velocity, it will probably only affect one or some of your taps.
Possible causes of supply and pressure issues
The most common causes for supply interruptions are bursts, home plumbing problems and network issues, including:
- an unseen leak
- an air lock or blockage in the pipework
- faults with private plumbing work
Your flow can also be affected by:
- high demand in the morning and early evening
- the size and condition of your service pipe
- the height of your building
If you're on a shared supply pipe, the number of neighbours that are also supplied by the same pipe can affect your water pressure.
If your pipes are in poor condition, changes in pressure can strain the pipework and cause it to burst, so it’s important you protect your pipes during cold weather and contact a plumber if you spot any damaged pipework.
What to do if you have no water or low pressure
If you have no water or low pressure there may be a problem in your area. You can check to see if something has already been reported on our interactive map.
Before you report a problem to us, there are some checks you can do yourself to work out what and where the issue is.
Check with your neighbours
If other people living on your street are having the same issue as you, it's possible that there's a problem in your area.
You should also check whether your neighbours have been doing any plumbing work on their homes. It's common that one pipe can supply more than one home, but your neighbours may not realise they've affected other homes.
If it's just your home or property that's being affected and your neighbours' supplies are all ok - contact a plumber for help.
If you've had some plumbing work done in the last 48 hours it could be related. It's best to contact whoever carried out the work, but you can also use our approved plumbers list to find a plumber near you.
Check your stop tap
It's worth checking to see if your internal stop tap is partly closed, is broken or has seized up.
You can usually find your internal stop tap under the kitchen sink, or in a bathroom close to where the water supply enters your home.
To make sure you’re getting the maximum water flow possible, check that your stop tap is fully open.
If the stop tap isn’t fully open, turn it gently and see if that helps improve the problem. Turn the stop tap left to open it and right to close it.
If you can't turn your stop tap it has probably broken or seized up. A broken or seized stop tap is very likely to be the cause of any issue with your water flow.
You should contact a plumber if your stop tap is broken or has seized up.
Test your water flow
You can easily test your water flow at home, using a one litre jug and a timer.
- Make sure all your taps are turned off completely, and any appliances such as a washing machine or dish washer are not in use
- Turn your cold kitchen tap all the way on and time how long it takes to and fill the one litre jug with water
Your tap should fill a one litre jug in around 7 seconds.
Solving problems with your flow
If it takes longer than 7 seconds, then it's likely that something is restricting the flow of your water. This could be an air lock or a blockage.
You can check for a blockage or air lock in your pipes:
- Fully turn the cold tap nearest your internal stop tap on
- Turn your internal stop tap off and on 7 to 8 times in a row
This should return your flow to normal. If the problem continues after that, you should contact a plumber to investigate.
Leaks can cause pressure and flow problems
Leaks aren't always obvious. They can be on pipes hidden behind furniture, under floors or in walls. There coud also be leaks on the private pipes undergound that connect your property to our network.
Leaks can cause a loss in pressure and reduced flow of water.
There are some tests you can carry out at home to check for leaks that you can't see.
If you think you have a leak, you'll need to get in touch with an approved plumber to investigate and fix the leak for you.
Problems caused by recent plumbing work
If you've had some plumbing work done in the last 48 hours, change in pressure could be related.
It's best to contact whoever carried out the work, but you can also use our approved plumbers list to find a plumber near you.
Things we are responsible for, and things you are responsible for
You and your water supplier split responsibility for water pipes and fittings depending on where the infrastructure is. Pipes within a property's boundary are the responsibility of the home-owner. Water meters, and infrastructure on public land, are our responsibility.
When the problem is our responsibility, we’ll fix it as quickly as possible. If the issue is your responsibility, we’ll provide all the advice you need to get it fixed.
When we do need to carry out repair work on our network, it’s our aim to ensure your service is restored in less than three hours, however larger jobs can sometimes take longer.
You have no hot water, but your cold water is flowing
If your cold water taps are working, but the water coming from you hot water is not heating up, this indicates an internal problem - possibly with your boiler - which a plumber should be able to help you with. You can find a reliable, local plumber using our approved list of plumbers.
Get in touch if you're still experiencing problems
If you've carried out the checks, but you're still experiencing problems with your supply, report the problem to us
and we'll investigate the cause.
You can also read and download our full water pressure policy guide.