RIO DE JANEIRO (AP) — At least 400,000 customers in Brazil’s biggest city still had no electricity Monday, three days after a violent storm plunged millions into darkness around Sao Paulo, the power distribution company Enel said.

The storm, with winds of up to 100 kph (62 mph), caused at least seven deaths, authorities said, and uprooted many large trees, some of which fell on power lines, blacking out entire neighborhoods. At one point on Friday, 4.2 million residents had no power, the newspaper Folha de S. Paulo reported.

In some apartment buildings, condo associations delivered bottles of drinking water to older residents.

José Eraudo Júnior, administrator of a 15-floor building in Sao Paulo’s Butanta neighborhood that didn’t get power back until Monday evening, said electricity went out for all 430 apartments Friday night.

Water in the roof tanks ran out by Saturday evening, while underground reserves could not be tapped because there was no power to run the pumps, he said.

On Sunday, residents were using buckets or empty bottles to collect water from the building’s swimming pool to flush their toilets, he added. With elevators out of service, some had to carry the water up 15 floors by foot.

“It’s not very common to see such a big power outage,” Eduardo Júnior said by phone. “Three days without electricity — nobody remembers such a thing.”

Enel Distribuição São Paulo, one of three companies providing electricity in Sao Paulo, said in a statement Monday afternoon that it had restored power to 1.7 million of its 2.1 million customers affected by the storm, or just over 80%. It said electricity would be reestablished for almost everyone by Tuesday.

“The windstorm that hit the concession area ... was the strongest in recent years and caused severe damage to the distribution network,” Enel said.