To get the best results from our online calculator, the water usage you enter should be your average consumption over 90 days (a quarter of one year).
You can find your water usage on your bill under the Unit column that ends with m3 - e.g. 125m3. The amount of days this figure relates to will also be shown in the same column.
Take the water usage figure and divide by the number of days the charge relates to then multiply to get the average for 90 days. For example:
125m3 ÷ 100 days = 1.25m3
1.25m3 x 90 days = 112.5m3 per quarter