Joann Pan Signs warn residents: “Do Not Drink the Water.” Cases of bottled water are available to all residents living in Haven Plaza.

For nearly 11 days, Isa Gonzalez and her two young children have been living in the dark, without heat or running water.

To get to their apartment at One Haven Plaza, they climb 17 flights of unlit stairs. The federally subsidized high-rise at Avenue C and 13th Street was one of the many buildings that lost power after Hurricane Sandy hit last Monday.

Electricity started flowing to the apartments in Two and Three Haven Plaza this week, though  – like many other buildings in Alphabet City – they are still without heat or water. But at One Haven Plaza, where electrical equipment in the basement was badly damaged by flooding, the situation is worse. Signs reading “Do Not Drink the Water” are posted in the hallways, next to elevators at a standstill.

Daisy Lopez, site manager of the three buildings, believes power may not be restored for a week. “We are telling everyone one week, but we are hoping sooner than that,” she said, wearing a scarf and hat in her unheated office yesterday.

Some of the building’s elderly tenants and families with young children had the option to take a limited number of vacant rooms at the Grand Street Guild housing development, affiliated with the plaza’s management company. But half of the residents remain, Ms. Gonzalez estimated.

Joann Pan Haven Plaza

“I live here even when there is no power, because my kids have to stay here because they have to go to school,” she explained in the building’s lobby, her breath clearly visible in the cold. Her son and daughter attend Washington Irving High School and the United Neighborhood Middle School, a couple blocks away.

During the day, she takes the train or a temporary shuttle bus to her job in Brooklyn. At night, she stays warm by using blankets and by boiling water in a pot (her gas is still is on).

Malo Ruiz has also been hiking up to his apartment on the 20th floor. He cared for his ailing mother there until Wednesday. “I had to take her to the hospital because she was short of breath,” said Mr. Ruiz, dressed in thick layers of clothing. “The elevator wasn’t working.” In need of routine dialysis, she’s now staying with Mr. Ruiz’s cousin.

With no elevator service, Henry Mendez, a 20-year resident of the complex, has been helping his neighbors with an important task: hauling up buckets of water, so they can use their toilets. “The hard thing is the toilets aren’t flushing,” Mr. Mendez said. “You have to bring water up. You need at least two gallons for one flush. You need at least three flushes a day, at least.”

Joann Pan Two Haven Plaza

Ms. Lopez has also been handing out food, blankets and water, and Good Old Lower East Side has been going door to door as well. Police officers are also checking in on remaining residents, and volunteers and staffers are serving hot meals and giving out supplies on the fifth floor of the buildings with power, from 7 a.m. to 7 p.m. daily.

Not all of One Haven Plaza’s residents stayed. Ariel Batist comes back during the day to pick up clothes, supplies and necessities from otherwise pitch-black apartments. “I had a sense that it wasn’t going to be a two-to-three-day type of thing, it was going to be for a while,” she said. “We figured my car was flooded in the garage down here; I have two young kids and we weren’t going to stay in the apartment.”

Yesterday evening, The Times reported that 75,000 Con Edison customers were without power, up from about 64,000 earlier in the day.

Carlina Rivera, a program manager at GOLES, told The Local that baby supplies are needed most. At the Sixth Street Community Center, at 638 Sixth Street, the organization is collecting items such as diapers, canned food, blankets, and fruits with longer shelf lives, such as apples and bananas.