A Guide To Water Pressure.
What Taps and Showers Will I Need in My Bathroom?

The type of system you have installed will determine how much pressure you will be getting. It is important to know what system you have when making a tap or shower purchase as not all taps and showers are the same. If you are unsure about what system you have or what pressure you are receiving, please consult with a qualified plumber.

Water Pressure

What determines high or low pressure?

Depending on the system installed, any system providing above 1 Bar of pressure is considered ‘High pressure’. Any thing below 0.3 Bar is considered ‘Low pressure’. The grey area between 0.3 and 1 Bar is largely ignored by manufacturers. This is because current UK water system types do not generally supply pressure in this bracket. This can cause an issue with some consumers as they might buy a tap that states 0.5bar pressure believing that this will work on a low pressure system and it does not with the exception it is fitted on the ground floor level of a two story building.

The current UK standards are:

Unvented System (High Pressure)

This kind of system is often fitted in newer or refurbished properties. Water is provided by a high pressure hot water cylinder, which will be located in an airing cupboard. Unlike a gravity system, an unvented system does not have a cold water tank in the loft. An expansion tank is usually visible on top of the cylinder. You cannot add a booster pump to this system to achieve a higher pressure and/or flow rate.

Gravity System (Low Pressure)

Gravity systems are the most common system in the UK. They tend to be found in older properties. There is normally a cold water tank in the loft and a hot water cylinder in the airing cupboard. Pressure is created by gravity, hence the name. The greater the vertical distance between the tank and the tap or shower head, the better the performance.
For example: Every 1 metre drop from the water tank typically equates to around 0.1 Bar in pressure. So your upstairs bathroom taps will normally sit around 2 metres below your tank, resulting in a water pressure of 0.2 Bar, and your kitchen taps will be around 5 metres below your tank, supplying you with around 0.5 Bar of pressure. You can therefore use kitchen taps with a slightly higher rating (up to 0.5 bar) as the distance between them and the cylinder is greater than the taps in the bathroom upstairs. You can add a booster pump to this system to increase flow.

Combi Boiler System (High Pressure)

A combination boiler – often referred to as a ‘Combi’ – is usually located in the kitchen and fires up the moment you turn on a hot tap. These are recognised as a high pressure system. You cannot add a booster pump to this system to achieve a higher pressure and/or flow rate.

Please be aware…

Figures quoted against products are indicative of their potential based on an adequate supply. They are not necessarily a definitive statement of what you will get, they are a maximum rating on performance and can vary depending on many factors including, but not limited to, the mains water supply and the pipe paths and bending within the household.

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