Calculating Your Roof Surface Area for Rain Harvesting: How Much Can I Save?

Calculating Your Roof Surface Area for Rain Harvesting  – Your roof surface area is the size of your roof which rainwater can fall on which can be harvested.  For single storey homes, your roof surface area will often be greater than your floor area however you will need to consider if it is possible to pipe all the water to one area for storage in tanks.

Your roof surface is the catchment area for harvesting rainwater which measures in square metres and will determine how much rainwater can be collected. It is important to know how large or small as rainwater filters, to filter out leaves and moss are designed for the roof area.

Calculating your roof surface area

Measuring the footprint of the house or commercial building you are going to be collecting water from for storage.  The Met Office has a useful rainwater calculator for your area for calculating the average rainfall in your area.  Whether the roof area is large enough will determine whether the water you can collect will be enough for your requirements.

Calculating your catchment capacity

Roughly speaking, the water catchment for your house or building will be worked out as follows – 1 millimetre of rain falling on 1 square metre of roof area will equal approximately 1 litre of water storage.

Rainwater harvesting filter kits filter prevent moss and leaves from going into your rainwater harvesting tank, whilst softening the water as it passes through the filter. Available as a basket filter or self-cleaning design, these filters suit every roof size whether it is a domestic house, an agricultural barn or a commercial factory

Rainwater tank options

Our rainwater harvesting tanks are available for above and below ground installations. Above ground plastic rainwater tanks are able to store up to 90,000 litres which can be used for agricultural sprayers off a grain store, water for dairy wash down from barns, pressure washers, greywater systems for flushing toilets for commercial factories and office blocks and a number of applications for washing and cooling in industry.

Below-ground tanks are available from 800 litres to 9,500 litres capacity, with the option of plastic or galvanised lid and a range of turret sizes.  Rainwater filters are available for removing leaves and moss out of the water coming off the roof to save a build-up of sediment in the tanks.  Some installations are legible for rainwater system grants – see more details here

For more guidance on Calculating Your Roof Surface Area for Rain Harvesting and rainwater harvesting tanks please get in touch.