One of the damaged water pipes feeding 27,000 Hamilton properties has now been fixed, but it will be late today before the second one is repaired.
Residents are still being asked to conserve water and several dozen had none at all when the pressure dropped yesterday evening.
The Eastern Main began leaking after a substantial section of the riverbank collapsed this afternoon but water is being supplied to that part of the city from the western main.
The water supply to the city's well-known gardens was also limited.
The City Council is urging residents to continue to use as little water as possible until the pipe repairs are finished.