Water systems within the UK
Which Water System am I on: Debunking Water Systems within the UK

Which Water System am I on: Debunking Water Systems within the UK


Author: Aqualisa


Whether you use your shower as a morning refresher or a night-time wind down, for many of us a good shower is part of our daily routine.

Alongside the obvious benefits of feeling clean, showering has been shown to aid sleep, improve immunity and circulation, and there are currently investigations in to how showering can improve mental health too.

So, we know that having a good shower can have a real impact on your wellbeing. In this guide, we’re going to discuss important considerations when looking at the types of shower we’d recommend.

Why is my water system important?

Understanding the water system that you have installed in your home is one of the most important considerations when picking the shower you want to install. The variety of hot water systems within the UK can significantly affect shower performance, so understanding the type of system you have and limitations this might bring is essential.

Before we jump in to delve into debunking UK water systems, however, we first need to visit water pressure and how this is fed into the home.

Water Pressure Vs Water Flow: What’s the difference?

It’s a common misconception that water pressure and water flow are the same thing, but this is not the case. We can think of water pressure as the force of the water through the pipes, and water flow as the volume of water that is delivered. The same amount of water will be delivered into a home, but the rate at which it arrives will be directly impacted by the force pushing it in.

Water pressure within the home could be bad due to a number of factors, but typically it is affected by:

  • The type of water system you have installed
  • Where your property is located in relation to a water reservoir
  • And the time of day you use your outlets

Simply put – the lower the water pressure, the worse the flow rate, but there are a number of products which have been specifically designed to counteract this.

Which water system do I have?

Whilst the function of all water systems is the same in heating and delivering hot water, the ways in which each system is fed and generates heat will vary and this can impact on the types of plumbing products that we’d recommend as a result.

Within the UK, there are 3 main ways in which we can access hot water supplies within the home –

  • Through a combi boiler system,
  • a gravity fed system
  • or a high pressure (or unvented) system.

What is a Combi Boiler System?

A combi boiler water system works by taking water directly from the main, heating this on demand and generating hot water almost instantly.

As there is no need for a separate a hot water tank in the house, a combi boiler system is a compact and efficient way to deliver hot water around the home.

Combi boilers are usually located in a garage, kitchen or downstairs cupboard, and as this system is fed off of mains water pressure, this type of water system can provide a powerful shower without the need for an additional pump.


The hot water feed tends to have a slightly lower pressure than cold feed, but this is due to the heating time required in a combi boiler. 

Combination Boiler Water System

What is a High Pressure System?

A High Pressure or unvented hot water system works by taking cold water directly from the mains and heating this in one of two ways.

The water can either be heated directly in the tank via a heating element or indirectly via an external heating system like a boiler.

As the water is heated, this causes pressure within the hot water tank, meaning that the stored hot water can be delivered at a higher pressure than within a combi boiler.

Unvented systems don’t require a cold water storage tank, but they do need a hot water cylinder within the house, which is typically located in an airing cupboard or utility room.

High Pressure Water System

What is a Gravity Fed/Low Pressure System?

Gravity Fed or Low Pressure water systems are one of the most common types of hot water system in the UK, and are often found in older houses.

Mains water is fed directly into a large cold water storage tank, which is usually located within a loft or roof space. As the cold water tank fills up, gravity allows water to be fed to the hot water cylinder below, where the water is then heated by an immersion heater within the tank or a back boiler.

Gravity continues to feed water from the cold tank above, creating the pressure needed to push the heated water from the hot water tank.

As this system relies on gravity to push the water down and create pressure, a gravity fed system typically delivers a low water pressure, although there are showers in the market that can counteract this and deliver an exceptional performance.

High Pressure Water System

Which Shower can I fit in my home?

Whilst it’s clear that a low pressure system can impact the quality of the shower you can achieve, there are a range of products available through Aqualisa to create a powerful and invigorating shower experience. This means that you won’t have to go to costly lengths of upgrading your water system to improve your shower pressure.

Showers will typically fall into 1 of these 4 categories: Smart & Digital Showers, Mixer Showers, Power Showers and Electric Showers. Each Shower type has installation benefits, but recommendation of each will be dependent on the type of water system you have.

Smart & Digital Showers

Digital Showers are one the newest additions to the shower market and were invented in 2001 by Aqualisa. In 2020, we enhanced this digital innovation with the introduction of the UK’s first Voice Activated Smart Shower, our Quartz Collection.

Smart showers counteract bad water pressure in a similar way to power showers, but the key difference is that the in-built pump is not placed on the wall, but is found within the discrete SmartValve unit supplied with every Smart shower.

This technology premixes the hot and cold water feed away from the showering area, delivering it with temperature precision every time.

These SmartValves are normally located under the bath, in an airing cupboard or in the loft, so offer a modern and minimal installation as the bulk of the pipework is removed from the shower.

Smart showers offer fantastic benefits to Gravity Fed homes, but are also the most versatile type of shower with variations to fit High pressure and Combi Boiler homes too.

Mixer Showers

Mixer showers are an affordable showering solution, with a range of styles and installation options available in the market.

As mixer showers have a hot and cold feed directly in to the back of the valve in the wall, this type of shower typically performs best on high pressure or combi boiler water systems, as there are no additional pumps increasing the water flow through the shower head.

Power Showers

A power shower is an ideal solution if you have a Gravity Fed water system within the home.

Power showers are simple to install and mix water from separate hot and cold water feeds in the wall, similar to mixer showers.

 The key difference with power showers, however, is that they contain an integrated pump in the unit which can deliver an exceptional showering performance under low pressure.

Electric Showers

It’s also important to highlight that many people simply don’t want to use their hot water system to heat the showers in their home. Electric showers are fed from cold mains water only, providing hot water on demand within the bathroom.

Electric showers are supplied in a variety of power ratings to get the best performance in the home.