Water Pressure Guide

Water Pressure Guide For Taps & Showers

The importance of understanding your water system

What is water pressure?

Water pressure is a term used to describe the flow strength of water through a pipe; it is measured in bar.

Why is water pressure important?

Whilst the majority of Crosswater products are compatible with most systems some high pressure (HP) products are designed to work with high pressure systems only. Products marked LP (low pressure) and MP (medium pressure) are also suitable for high pressure (HP) systems.

How do I select the right product?

In order to select a showering system that will give optimum performance you need to identify the water pressure the plumbing system in your home gives you.

Find your plumbing system

The information below is given as a guide only. Please refer to your qualified installer for full compatibility
with your hot and cold water system.

Hot gravity & cold gravity/mains

Low pressure systems (LP min 0.2 bar)

  • You have a cold water storage tank in the loft.
  • You have a hot water cylinder.
  • You do not have a shower pump installed.

If all of the above apply to your home you can choose any product marked with LP (min 0.2 bar). 

Note A gravity fed system provides MP (0.5 bar) to fittings downstairs in a 2 story property where the cold water tank is in the loft.

Combination boiler

Medium pressure systems (MP 0.5-1 bar)

  • You have a combination boiler that heats water on demand.
  • You do not have any storage tanks.
  • You do not have a shower pump installed.

If all of the above apply to your home you can choose any product marked with LP, MP or HP1.

Mains high pressure

High pressure systems (HP1/2/3 2-3 bar)

  • You have an unvented cylinder with an expansion cylinder.
  • You have no cold water tank in the loft.

If either of the above apply to your home you can choose any product marked LP, MP, HP1, HP2 and HP3 (minimum 1/2/3 bar).

Pump assisted

High pressure systems (MP to HP4)

  • You have a booster pump fitted.

Where a gravity flow of water is in excess of 0.6lpm, this is known as a ‘Positive Head’ condition (e.g. when your shower head is positioned lower than your cold water storage tank). In this situation, a positive shower pump can be used. A ‘Negative Head’ condition is when the gravity flow of water is less than 0.6lpm (e.g. when your shower head is positioned above the cold water tank level). In these conditions, a negative head pump must be used. 

Negative shower pumps will work in both positive and negative head conditions. So for example, in a situation where there is a shower head above and below the water tank level; one negative shower pump can be used for both. 

With the right pump, you can choose any of our products.