Mayor Caroline St-Hilaire told an early-morning news conference Friday that tests on the water supply would continue.
She said providing water to daycares and seniors residences would be a priority.
A non-consumption advisory, put in place late Thursday, is still in effect in several communities, including:- Saint-Hubert.
The advisory followed residents' complaints that their tap water smelled like gas, a day after 28,000 litres of diesel spilled into the St. Lawrence.
Water quality tests were conducted Thursday to determine if the ban could be lifted.
Despite the advisory, public health officials said anyone drinking tap water or cooking with it face a very low chance of getting sick.
Many people spent spent Thursday stocking up on bottled water.
Longueuil had promised to provide bottled water, but that plan didn't go off smoothly.
There were long lines at several distribution centres as residents waited for the arrival of supplies.