This section describes the application and review process for obtaining approvals to construct or repair vaults under the sidewalks of New York City streets. NYC DOT issues permits for two types of vaults: building vaults and transformer vaults.

A building vault, as described in Section 2-13 of the Highway Rules, is any opening below the surface of the street that projects outside of the property line and is covered over, except for those openings: (1) used exclusively to access, by means of steps, the cellar or basement of any building; (2) used primarily for light and ventilation; (3) constructed or maintained by utility companies (including transformer vaults); and (4) which are subways, railroads and related structures.

A transformer vault is a subsurface structure or room that houses electrical transformers and appurtenant equipment. Transformer vaults are typically installed, owned and maintained by an electric utility company. The city has master revocable consent agreements with electric utility companies that allow them to occupy and use city property for transformer vaults.

The construction, alteration or repair of any building vault or transformer vault requires a permit from NYC DOT. Most vault work also requires plan approval and a permit from DOB. In some cases, approval from the LPC (if the vault is in an historic district) or the Metropolitan Transportation Authority (MTA) (if the vault is near a subway or tunnel entrance) is required. In addition, a vault license from NYC DOT's Office of Franchises, Concessions and Revocable Consents is required to construct a new building vault or enlarge an existing building vault.

Applications for NYC DOT vault permits are reviewed on a case-by-case basis. Applicants should contact the NYC DOT Plan Examination Unit (PEU) of the Permit Office to initiate the application process and to determine specific requirements for a permit and a license, if required. A list of the forms most commonly used during this process can be found in Appendix B, Forms. A $35 filing fee is required for all vault applications.