Water pressure

If you have a problem with low or high water pressure, the advice below could help you to find and fix the issue.

About water pressure

Pressure is the force that pushes water through pipes and it affects the flow from your tap.

The amount of pressure in your home can depend on:

  • the height above your home of the service reservoir or water tower providing your supply. Properties at the top of a hill may receive lower pressure than those at the bottom
  • how close you live to one of our pumps.

Pressure can also vary at various times of the day – mornings and early evenings are when there is often more demand, and this can cause low pressure.

Inside your home the water pressure can be affected by your plumbing such as:

  • the width or texture of a pipe
  • a pump/regulator or pump/regulator setting
  • the level of water in an attic water tank.

Water flow

Water flow refers to the amount of water coming out of a tap in a certain amount of time.
This can range from a trickle to a gush.

Water flow depends on the size of your water supply pipe, but it can also be affected by changing a showerhead or tap.

  • Older properties: These usually have water pipes that are 15mm to 20mm in diameter. It means the flow through these pipes may only be enough to run one tap. You may experience low flow if there are several taps or appliances being used at the same time.
  • Modern houses and flats: These usually have 25mm diameter water supply pipes which can give a higher flow rate – these pipes are more suitable for today’s appliances.

We are legally bound to provide all customers with a minimum pressure of 10 metres head, and a flow rate of at least nine litres per minute at the boundary of your property. This should be ideal for day-to-day use. This should be powerful enough to fill a one-gallon (4.5 litre) container within 30 seconds.

If there are several taps or appliances running at the same time, there may not be enough water for them all and the flow will be low.

Low pressure

If you are experiencing low pressure in your home, our step-by-step guide may help.

Step 1: Planned or emergency work

Check whether we are working in your area - this could be affecting your water supply temporarily. If it’s planned work, we will let you know by letter 48 hours in advance.

Step 2: Test your stop tap

Usually, you will find your stop tap under your kitchen sink. To test whether it is fully open, turn it off (clockwise) and then back on (anti-clockwise) – repeat a few times.

Step 3: Check your isolation valves

These may have been adjusted to reduce high pressure.

Step 4: Look for a leak

A leak could be affecting your water pressure or flow.

Step 5: Check your kitchen cold tap

If this is working fine but you have low pressure or no water elsewhere in your home, the problem is likely to be your internal plumbing.

Step 6: Contact a plumber

A plumber can help to improve the water pressure in your home. If your plumber thinks you have a low pressure problem, we will need to check if work in your area is causing it.

Step 7: Contact us

If the steps above are unsuccessful, please contact us and we’ll arrange a visit to test the pressure at your kitchen cold tap. After we have carried out our checks, we will provide written confirmation of the test results.

High pressure

There could be several reasons for a sudden increase in water pressure you have not been pre-warned about, such as a mechanical fault or emergency works to the water mains in your area.

Step 1: Check your kitchen cold tap

If the high pressure is affecting your cold water kitchen tap and your neighbours are also affected there could be an issue with our water mains.

Step 2: Other taps

If the high pressure is affecting another tap in your property, there is probably an issue with your internal plumbing. For this you will need to contact a plumber.