Why do some cities ban water sprinklers?

Garden sprinklers use water very inefficiently and so they are quite wasteful. During hot, dry weather we must conserve water to use for more important things than keeping our lawns and gardens pretty.

Watering via sprinkler on hot days sees most of the water evaporate and not actually be used by the plants in question. IN some countries where water is a premium resource watering of any plants is undertaken by "direct supply". This means water is piped to root areas of plants and therefore reduces substantially the water vaporization.