Consumers in those areas needed to "conserve water where possible".
"After seven years with no restrictions, we are now in the position of needing to implement this to ensure that we have enough drinking water to go around, and that we respect the principles of Te Mana o te Wai," Aitken said.
"Residents need to limit non-essential water use wherever possible and help us by looking for and fixing any leak on your property or farm. All water savings can make a difference."
The restrictions will be in place until further notice, although the council expects them to be lifted in early April.
Ways to help conserve water include avoiding watering lawns, taking a short shower instead of a bath, fixing leaks and dripping taps and using full loads to wash clothes and dishes.
Reducing how often cars and boats are washed, as well as refraining from washing down driveways or buildings, are other suggestions.
• Any leaks on the public system can be reported to the council on 0800 111 323.