Officials said 300 properties in Ocean Village, Southampton, had been left unsafe because of the problem.
The three apartment blocks were initially evacuated on Sunday and then fully closed on Tuesday.
Firefighters said a basement had flooded, cutting the electricity in the Admirals Quay development.
The problem has affected flats in Blake Building, Moresby Tower and Hawkins Tower, leaving them without communal or emergency lighting, lifts, fire defence systems or a fresh water supply.
Management firm SDL Bigwood has said people will be allowed back home on Saturday morning "at the earliest".
In a letter to residents, it said the issue posed a "major risk" to safety in the buildings.
A spokesman said some people had been allowed to stay in their homes on Sunday night, before it "became clear on Tuesday the entire building needed to be placed in lock down".
All three buildings share the same water tank and electricity mains panel, he said.
He said SDL was currently working with insurers, who have appointed a critical management team and agreed to reimburse accommodation costs incurred by owners of the flats.
A spokesman for Hampshire Fire and Rescue Service said they were called on Sunday night to an automatic fire alarm.
He said: "This was caused by flooding to an electrical system which resulted in a power cut. Once we ascertained there was no fire we handed the situation over to the housing management company."
Pauliina Aminoff, who lives on the 22nd floor, said she had friends visiting when the fire alarms went off.
She said: "We all ran out and we were waiting for three hours with no information whatsoever. Just before midnight we got back in and the emergency light was off so it was completely dark, no electricity no water.
"There needs to be someone to take responsibility, they need to inform us."
Ms Aminoff also said the management company needed better emergency signs and lights.
SDL said it complied fully with health and safety regulations.
Fellow resident Evin Huang said she was "very shocked" and it had been "very inconvenient" because management were telling them to book hotels on a day-to-day basis.
Hundreds of people have been forced out of their homes for up to a week after a water pipe burst caused a "complete loss of power".