The city is preparing to move dozens of troubled teens off Rikers Island this fall, but the new Bronx detention facility in which they’ll be housed will in some ways be even more restrictive than jail.

Adolescents who are detained in the new facility, the Horizon Juvenile Center in Mott Haven, won’t be able to make daily phone calls and do legal research in a law library.

They will no longer have their own bathrooms and drinking water, as they currently do inside individual jail cells. Instead, they will ask to visit the loo and be escorted by staff within five minutes of a request.

For at least the first two years, correction officers will have to help staff the facility, a matter that has sparked sharp criticism from advocates as well as the officers themselves.

“I’m very concerned,” said JoAnne Page, who heads the Fortune Society. “We only get one chance to make a first impression. How we start this is so important.”