N.Y.C. Admin. Code § 6-310: § 6-310 Paper waste reduction.

a. Any printer purchased or leased by any agency that can print at a rate of twenty pages or faster per minute or that is considered a local area network printer shall have the capacity to print double-sided. Any copier purchased or leased by any agency that can print at a rate of twenty pages or faster per minute shall have the capacity to print double-sided and shall perform equally well with paper containing postconsumer material as with paper containing no postconsumer material.

b. Notwithstanding section 6-302 of this chapter, this subdivision shall apply to any printer or copier purchased or leased by any agency after January 1, 2007 and, to the extent practicable, to any printer or copier purchased or leased by any agency before such date. The default parameters of any printer with the capacity to print double-sided, and any computer that utilizes such printer, shall be set to duplex mode, such that the printer prints double-sided pages. The default parameters of any copier with the capacity to print double-sided for which the default parameters can be adjusted, shall be set to duplex mode, such that the copier places images on both sides of a copy sheet, performing one-sided to two-sided copying, and two-sided to two-sided copying.