N.J. Stat. § 40:63-71
Any two or more municipalities, by their respective governing bodies, or by their boards charged by law with the construction of sewers and drains in such municipalities respectively, may unite and jointly cause to be made, at their joint expense, by competent engineers, surveys, maps and plans of, and reports, specifications and estimates for, any proposed improvement or works authorized by section 40:63-70 of this title, which such municipalities may desire jointly to construct, maintain and operate; and for such purpose, and before determining upon a final route or location for such proposed improvement or works, may, by their engineers, agents and servants, lawfully enter upon any lands or waters, to explore and make surveys, and do all necessary preliminary work, doing, however, no unnecessary damage or injury to private or other property.
N.J.S. § 40:63-71