What Capacity Rainwater Tank Can I Fill?
Catching rainwater to fill your water tank
When researching what size or style rainwater tank to purchase one of the major factors to consider is how much rainwater you can expect to catch from your house or shed. If you are planning to build or extend your house or shed, it is a good idea to calculate whether you will catch a sufficient amount of rainwater with the roof you intend to build. When dealing with a pre-existing structure you can easily calculate the volume of water you will be able to catch. If you will be in a water catching deficit you can easily add extra guttering and downpipes allowing you to fill the rainwater tank more quickly.
When calculating the amount of rainwater you can catch, you need to know 2 things:
1) The combined roof area that you will be able to catch the rainwater with (m2).
2) The average annual rainfall in your area.
1mm of rainfall is equal to 1L/m2. With this formula you can calculate how much rainwater you can expect to catch on average. This will give you a much better idea of the size rainwater tank you will require to suit your needs.