Last night, I finished a weeks sample of our rainwater consumption, which I am taking to be the mean. Here are a few facts and figures for your delight and delectation:
- Our rainwater consumption in one week is 1.86 kilolitres (cubic metres).
- We harvest 1.86 kilolitres for every millimetre of rain that falls.
- Even if we assumed two kilolitres of water consumed every week, this only equates to 104 kilolitres per year.
- 104 kilolitres equates to 186 millimetres of rain harvested.
- We have had approximately 150 millimetres of rain this year, equating to a harvest of about 84 kilolitres, or approximately 80% of our annual consumption, based on two kilolitres a week.
- Rainwater is used for everything apart from:
- Horse troughs
- Toilet flushing
- Outside taps
- Lawn irrigation
- All water used in the house is re-used for irrigation after passing through an aerobic wastewater system.
This isn't a perfect situation, but I am pleased; our rainwater system is virtually self-sustaining, even with a below-average rainfall.