Gisborne District Council has issued an urgent warning to all residents after a leak in the main water supply pipe.
The leak has put pressure on reservoirs and if restrictions are not obeyed, the city will not have enough water to meet demand.
The Council has put a total ban on all outdoor water use - no washing your car, watering your garden or filling swimming pools.
Industrial water users are being told they must put their water shortage contingency plans into effect immediately.
A spokesperson for the Council said they do not yet have any idea what caused the leak, or how long the restrictions will be in place. The Council will update the community within the next few hours.
Staff and contractors are currently on-site investigating the cause, and potential fixes.