An account of domestic water cost in five Australian cities is depicted in the given table.

Overall, except in Adelaide and Perth, the usage charge per kilolitre does not vary much when it is used above the ideal limit, and this is reflected in the average household bill.

As per the table, the usage charge per kilolitre of water, when it is used up to 125KL is the highest in Sydney, with just under an Australian dollar. The city which closely follows Sydney in this category is Brisbane ($0.81). The charges per kilolitre in other cities range from $0.42 to $0.78.

Turning to the cost per kilolitre, when the household uses over 125KL, Perth stands first with $1.50, which is more than thrice when it is used under the limit. In Adelaide, it is more than double when used less than the set limit.  Melbourne and Sydney charge the same per kilolitre, when used over 125KL. In Brisbane, the cost is slightly higher, but none of these three levied more than an Australian dollar.

In case of the average bill per household, except in Melbourne ($253), the water charges range between $310 and $332, with Perth being the city with the highest water bill.