The most common source of water harvesting is by Rainwater Tank. For most of us living in larger cities, collecting rainwater seems to be the new fad, however for those living in the country its a way of life. Many local councils, water suppliers and state governments encouraging residents to install a rainwater tank, usually with the offer of a rebate.
With a rainwater tank, you’ll collect most of the rain (around 80%) that falls onto the areas of your roof you have connected to gutters and downpipes into your tank.
If you know the rainfall in your area (check with the Bureau of Meteorology), you can calculate the likely tank capacity. Simply multiply the roof area by the maximum concentration of rainfall over 2 months of your wettest season. You have to allow for your consumption for the whole year.
An average roof in Melbourne can supply around 80 000 L of water a year. In Sydney and Hobart that figure could be 100 000L, and in Brisbane around 150 000L.
