Rainwater Calculator UK

Rainwater harvesting can be produced from any kind of building, agricultural farming sheds & outbuildings, offices blocks, small restaurants & cafes, manufacturing warehouses or industrial uinis, as well as the humble family house.

The amount of water harvesting that can be used, results from the potential capture area of the roof, our tanks (above or below ground) can be situated at location of any downpipes. The water collected from the roof can be a cost-effective way to reduce costs associated with your personal water usage.

A simple storage tank fitted to your stormwater drain collects falling rain from guttering and downpipes. A filter can be installed into our tanks, which removes leaves and other debris from rainwater before entering the tank. Water pumps can also be used to pump water troughs and water cisterns.

How much rainwater can I collect?

It is important to ensure that the system you choose meets all of your requirements. In general, in order to collect as much rainwater as possible use the following formula for an initial calculation.

Calculation

Roof area (footprint) in square metres X annual rainfall in cubic metres.

(650ml = 0.65m3), divided by 12 = average monthly rainfall capture.

Example

450m2 x 750ml = 337.5 (m3), divided by 12 = 28.125m3

Or 28,125 litres per month on average.

We suggest storing an average of 2-3 months quantity of rainfall (keep in mind you may get 3 months) worth in your wettest month.