A boil water order has been in effect for Harbourview subdivision in Red Head since Monday evening.
Saint John Water imposed the boil water order to residents and businesses after a power failure, a news release said.
The notice was being hand-delivered to affected users.
The city is also asking residents to share the information with their neighbours, especially those living in the affected area who may not have received the notice.
This includes people in apartments, nursing homes, schools and businesses.
Residents have been advised to not drink the water without boiling it for at least one minute first, since boiling kills bacteria and other organisms in the water. Otherwise, people should use bottled water.
Boiled or bottled water can be used for drinking, brushing teeth, making coffee or tea and washing vegetables that will not be cooked.
According to Saint John Water, people whose immune systems are compromised, including the elderly, infants and people who've had organ transplants, are on dialysis or have HIV/AIDs, should be careful to use a safe source of drinking water.