If you are an Aussie relying completely on the state-provided water supply, you are pitting yourself against the country’s robust freshwater vagaries. Installing water storage tanks in your house is vital, perhaps even more important than installing burglar alarms but how do you determine the size of the rainwater tank that your house would need? Here is a quick size guide for rainwater tanks in Australia.
The best starting point for calculating the size of the Aussie water tanks needed is the average rainfall data for your area. Remember that our country’s rainfall varies wildly from year and year and you must obtain data including the average rainfall and probable dry spells from a reliable source like the Bureau of Meteorology.
Your Household’s Water Consumption
Next, approximate the volume of water your household will require from your water storage tank. Count the number of members, average water consumption per person and outline all activities where water from the tank will be used. This number can run into tens of thousands of liters in bigger households.
Roof Catchment Area
This is the area that will collect rain water and empty it into the tank. Calculate total rainwater catching area including all roofs, slopes and eaves. This value will be less than 150 square meters for smaller houses and greater than 200 square meters for larger ones.
The size of your tank will depend on the average rainfall, catchment area and required volume. In addition to these, a fourth factor may be laid out as the security of supply that is the probability of a reservoir meeting all of the household’s demands. Households in areas with greater average rainfall, consumption, catchment areas and need for security will require larger Aussie water tanks.
Lastly, many local governments in most states provide pre-calculated ranges of Aussie water tank sizes based on the area’s average rainfall and house specifications. For example, in South Australia (SA), THE South Australian Water Corporation provides sizes for rainwater tanks. Make sure to check with your local authorities while determining your tank’s size.