The council said usage has "rocketed" following a period of hot weather.
"We hope our communities will respond positively to avoid the need for further restrictions and we will be closely monitoring use over the next few days," Hastings District Councils three waters manager Brett Chapman said.
"Our water is taken from the aquifer – not only do we need to conserve it for our household use, we need water for the crops that our local economy relies on and to ensure our streams and rivers do not become too depleted," he said.
The council said it was conserving water by only watering sports fields for the safety of sports players and having roundabout gardens and hanging baskets on timers to operate at off-peak times.
The council recommended residents can conserve water by not washing cars, not watering lawns, taking shorter showers, keeping grass longer which requires less water, only using the washing machine for a full load, and using a swimming pool cover and avoiding topping up water levels.