Rainwater harvesting systems are becoming commonplace in many buildings across the UK. With a rising tide of regulations surrounding sustainable drainage, it is important everyone understands the different systems on offer. After all, the buildings we are constructing now may still be operating in 50 years’ time, so every developer and contractor should be considering improved water efficiency on projects. Today, we are going to be using this blog to explain more about the Stormsaver Combi Rainwater Harvesting System which is the most common type of rainwater harvesting installation in the UK.

First things first, the name ‘combi’ refers to the type of control panel for the rainwater harvesting system. Stormsaver developed the unique Combi Rainwater Harvesting System to combine the benefits of pressurised, and gravity fed systems. Unlike pressurised and gravity fed systems, the combi control unit contains pumps, controls, automatic mains water top up, and break tank in one unit.

Our combi control unit can be supplied in a range of capacities, including 225, 400, 620 litres. This refers to the break tank capacity and is sized by our team based on your demand.

 Combi rainwater harvesting system
Why combine?
  • Ease of installation – just connect the combi control unit up to the incoming electrical and mechanical services and go! It also reduces the risk of incorrect installation as the unit is pre-built by us, here in the UK.
  • Simple to maintain – all system components are in one place, rather than being spread out in multiple locations.
  • Centralised monitoring – the unit can monitor components to ensure the systems is healthy and report any faults back to building management services.
  • Standalone pressurised rainwater harvesting systems contain a pressure vessel. If this fails, the water supply may be interrupted. The Combi removes this risk.
  • Reduced space requirements – the single unit is ideal for buildings where plant space is at a premium as all components are enclosed within the unit.
  • Reduces legionella risk – eliminates the need for gravity fed water supplies which come from a header tank often located high up in a building. Header tanks are more prone to legionella risk due to higher temperatures.
How does a Combi Rainwater Harvesting System work?

Just like any other system, rainwater is collected via roof drainage points and fed into a pre-tank filter arrangement. This filter removes debris such as, leaves and avion items. The Combi control unit is compatible with both above ground and below ground storage tanks.

When demand for a sustainable supply is detected by the control panel, reclaimed rainwater is drawn through a submersible pump and into the break tank. During periods of low rainfall, our control panel will automatically top up the break tank with mains water ensuring it can always deliver a constant supply. TIP: cheaper systems may undersize the break tank to save on costs, but this can lead to system failure within the first 12 months as supply cannot keep up with demand.

Reclaimed rainwater is then distributed to usage point via our variable speed booster set. Not only do variable speed pumps reduce energy consumption, but they can also extend the life of the pump. TIP: Alternative systems will use fixed speed pumps as they are cheaper. Yet these pumps will have a reduced lifespan compared to variable speed solution.

Learn more about how the combi rainwater harvesting systems works here.

Interested in learning more?

We offer a FREE Rainwater Harvesting CPD service for organisations looking to learn more about water reuse. Book here or get in touch with our team here.

Written by Matt
Water Reuse Specialist

My role as a Water Reuse Specialist means I get to keep up to date with all things water conservation. My favourite water saving tip is to turn taps off when brushing your teeth! I think rainwater harvesting and the water reuse industry is exciting, and I love sharing updates with our customers. View Matt’s Stormsaver profile here.

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Constructionline Gold Member CHAS Accredited UK Rainwater Harvesting Association Member Safecontractor Approved Waterwise Affiliate UK Business Awards Winner 2022