Here are some handy tools for you to calculate rainwater storage potential
First up, click here (or the image below) to go to our online calculator tool which will automatically determine the tank size you require and the ongoing savings you can expect from your rainwater harvesting system:
The manual example calculations in the PDFs below will also assist you in determining appropriate tank sizes and payback periods.
This information sheet contains a formula to help you measure your roof catchment area.
The Met Office link below will give you the rain fall in your area, this can then be used to help size your rainwater storage tank accurately: