Substantial Completion refers to a stage of a construction or building project or a designated portion of the project that is sufficiently complete, in accordance with the construction contract documents, so that the owner may use or occupy the building project or designated portion thereof for the intended purpose.
Example of a State Statute (Kentucky) defining the term:
KRS § 371.410 ( Kentucky revised statutes; TITLE XXX Contracts ; Chapter 371 Formality and Assignability of Contracts -- Installment Sales Contracts Kentucky Fairness in Construction Act)
"substantial completion" is the point at which, as certified in writing by the contracting entity, a project is at the level of completion, in strict compliance with the contract, where:
(a) Necessary approval by public regulatory authorities has been given;
(b) The owner has received all required warranties and documentation; and
(c) The owner may enjoy beneficial use or occupancy and may use, operate, and maintain the project in all respects, for its intended purpose.
Partial use or occupancy shall not necessarily result in the project being deemed substantially complete and shall not be evidence of substantial completion.
KRS § 413.135 says
The term "substantial completion" shall be construed to mean the date upon which the owner of the structure, project, or facility first entered upon the occupancy or commenced the use thereof.