Hi Roland,
Indeed your water usage is high. It is great to see that you are looking into it.
Working backwards $8000 equals about 3,846kl per annum. The Green Strata website shows that the average water usage in apartments should be between 200 – 300 litres /per bedroom/day.
In your instance, the usage (assuming they are 12 x 2 bedrooms) appears to be about 440 litres per bedroom/per day which would put you in the high usage category.
Most water usage in apartment buildings is known to be within apartments – 86%. Things to think about – are there likely to be mainly single flush toilets, old non-water saving shower heads, leaking taps & showers in your building?
If you think this likely to be the case suggest you get an estimate for Waterfix® from Sydney Water
https://www.sydneywater.com.au/SW/your-home/helping-you-save-water/waterfix-strata/index.htm
There may also be some kind of leak somewhere on common property that is not immediately apparent. Worth investigating.
And just to clarify the $700 charge you mention to each unit is the standard fixed charges which include water & wastewater service, not to be confused with actual usage. Usage charges are most commonly charged to the strata scheme as it is only recently that individual water meters have started to be installed in strata buildings.
Hope this helps explain.
Strata Answers
strataanswers.com.au