Multi-unit waterways calculator

Use this spreadsheet to calculate the water consumption of a multi-unit residential development with and without water saving features. This calculator covers dual occupancy through to multi-storey apartments.

Download the calculator (XLS 14MB)

Information you will need

To use the spreadsheet calculator, you will need to know:

Information for multiple rainwater tanks or multiple greywater tanks can be grouped together if the size, collection area and end uses of the water sources are equivalent, for example:

there are multiple rainwater tanks and they all have 100m2 of roof area flowing into them, they are all 2000L in volume and are all used for garden irrigation, toilet flushing and cold water laundry. the volumes can be considered as one tank and collection area can be considered as one roof. This principle only works if all of the volumes, roof area end uses are equal. If this is not the case, then they need to be considered separately.

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