=+3 City water bill, which is calculated as follows:

First 1 000 000 litres or less $1000 flat fee Next 10 000 litres $0.003 per litre used Next 10 000 litres $0.006 per litre used Next 10 000 litres $0.009 per litre used and so on and so on The litres of water used vary proportionately with the quantity of production output.