45 CFR §13.22

1. (a)The applicant must file and serve its application no later than 30 calendar days after the Department's final disposition of the proceeding which makes the applicant a prevailing party.
2. (b)For purposes of this rule, final disposition means the date on which a decision or order disposing of the merits of the proceeding or any other complete resolution of the proceeding, such as a settlement or voluntary dismissal, becomes final and unappealable, both within the agency and to the courts.
3. (c)For purposes of this rule, an applicant has prevailed when the agency has made a final disposition favorable to the applicant with respect to any matter which could have been heard as a separate proceeding, regardless of whether it was joined with other matters for hearing.
4. (d)If review or reconsideration is sought or taken, whether within the agency or to the courts, of a decision as to which an applicant believes it has prevailed, proceedings on the application shall be stayed pending final disposition of the underlying controversy.