Usage & CapacityUsage & Capacity
How can I calculate how much water I currently use?
Use the following table as a guide to calculating your average weekly water consumption. For example, an average 2 person household with garden would use approx 4,760L of water per week.
| Household Occupancy | Bathroom | Laundry | Kitchen | Garden | Subtotal (per day) | Total (per week) |
|---|---|---|---|---|---|---|
| 1 person | 250L per day | 120L per day | 35L per day | 135L per day | 540L | 3,780L |
| 2 people | 360L per day | 130L per day | 40L per day | 150L per day | 680L | 4,760L |
| 4 people | 650L per day | 150L per day | 45L per day | 165L per day | 1,010L | 7,070L |
How much rain will it take to fill the tank?
This is a simple calculation. 1mm of rain on every square metre of surface area results in 1 litre of water into the tank.
Let's say that your house roof is 12 metres long by 10 metres wide. 12m x 10m = 120m2. If you had a very brief storm that dropped 1mm of rain on the roof, you would receive 1mm x 120m2 = 120 litres of rainfall into the tank. A larger storm comes through and drops 25mm of rain: 25mm (rainfall) x 120m2 (roof area) = 3,000 litres of rainwater into your tank.
This calculation works for any roof area; all you need to know to calculate your roof surface area is:
