Rainwater Harvesting Calculator UK: How Much Rainwater Can I Save?

Rainwater harvesting calculator UK – rainwater harvesting can be carried out on any building whether it be an agricultural building, an office block, a small restaurant, manufacturing or industrial building down to a domestic house.

In each case, the amount of water harvesting, and which can be used is down to the potential capture area of the roof, where the tanks (above or below ground) can be sited and the location of the downpipes. This water – collected from the roof – can be a cost-effective way to reduce costs associated with your water usage.

A storage tank is fitted to your stormwater drain from your roof, this falling rain from guttering and downpipes enters the tank through a filter which removes leaves and other debris before entering the rainwater tank.  Water pumps can pump water troughs and water cisterns,

As a guide, a 900m2 roof area with 750mm of rain a year can yield up to 600,000 litres through rainwater harvesting

Rainwater Harvesting Calculator

It is important to ensure that your system fully meets your requirements and options. In general, you should collect as much rainwater as possible, however, there is little point in collecting a lot of water if you do not use it, or of the use of the water is too high for what you can save consideration to mains top-up will need to be considered.

Use the following formula for an initial calculation – our online calculator is here

Roof area (footprint) in square metres x annual rainfall in cubic metres.
(650ml = 0.65m3), divided by 12 = average monthly rainfall capture.
e.g., 450m2 x 750ml = 337.5 (m3), divided by 12 = 28.125m3 or 28,125 litres per month average.


What can Rainwater Be Used For?

Much of the water we use does not have to be purified (potable/of drinking water quality).  Conservative estimates indicate that in domestic applications, 55% of the water used could be substituted for rainwater increasing to 85% of water when considering the amount of water used for commerce, industry, and agriculture.

Rainwater is free, and by harvesting this resource for our useS, we not only provide ourselves with an independent water supply during drought conditions or times of regional water restrictions but also save on water bills.

Rainwater Site Visits & Installers

To collect rainwater successfully for long term rainwater storage, the correct tank size and installation of the guttering and tank is critical. Enduramaxx work with several installers around the UK who can carry out site visits and water use and savings audits around water quality issues surrounding the treatment and reuse of rainwater. Sometimes filtration or disinfection may be required for the use you are looking at using the water for and we advise discussions around this. In short, we can work with you to develop a rainwater harvesting system that will work for you.

How Much Rainwater Can I Save?

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