Use this spreadsheet to calculate the water consumption of single residential dwellings with and without water saving features.
Download the calculator [2.7 MB]
Information you will need
To use the spreadsheet calculator, you will need to know:
- the number of bedrooms
- the water rating for shower head, dishwasher, toilet and clothes washer
- the site area
- total roof area
- all rainwater tank information
- all grey water system information
- any swimming pool, spa or pond information.
Insert these details into the light green cells.
Calculating water ratings
Tap and shower water ratings can be measured by using a stopwatch and a bucket:
- Turn on the tap/shower to full and measure the volume of water used in 15 seconds
- Multiply by 4 to get the water consumption for a minute (L/min)
- Compare this water consumption with the Star rating table located on the indoor tab in the water reduction calculator
Most modern appliances have a water consumption rating.
| Star rating | Water saving |
|---|---|
| 1 star | Little or no water saving features |
| 2 star | Minimal water saving features |
| 3 star | Moderate water saving features, now the minimum standard of water saving required in the ACT for fittings |
| 4 star | Good water saving features |
| 5 star | High water saving features |
