45 CFR § 1321.15
Duration, format and effective date of the State plan
April 14, 2021
(a) A State may use its own judgment as to the format to use for the plan, how to collect information for the plan, and whether the plan will remain in effect for two, three or four years.
(b) An approved State plan or amendment, as indentified in §1321.17, becomes effective on the date designated by the Commissioner.
(c) A State agency may not make expenditures under a new plan or amendment requiring approval, as identified in §1321.17 and §1321.19, until it is approved.