Rainwater planning
RainwaterTo frequently asked questions
Answers about roof area, rainfall, tanks, filters, reuse, privacy and calculator limitations.
Is roof area the sloped surface area?
Rainfall yield uses the horizontal projection of the catchment. The roof yield tool helps calculate it.
Is a larger tank always better?
No. Beyond a certain size, additional demand coverage may be small. Use the optimiser and compare cost.
Do IMGW profiles forecast next year?
No. They are averages for 1991–2020. You can enter your own data.
Can rainwater be drunk?
The service does not assume this. Potable use requires suitable treatment, testing, plumbing and regulatory compliance.