40 CFR 791.37: The award.

(a) Time of award. The award shall be made promptly by the hearing officer and, unless otherwise agreed by the parties, no later than 30 days from the date of closing the hearings, or if oral hearings have been waived, from the date of transmitting the final statements and proofs to the hearing officer.

(b) Form of award. The award shall be in writing and shall be signed either by the sole hearing officer or by at least a majority if there is more than one. It shall contain a concise statement of its basis and rationale, and a timetable for payment of any ordered reimbursement.

(c) Delivery of award to parties. Parties shall accept as legal delivery of the award the delivery of the award or a true copy thereof by certified mail to the party at its last known address or to its attorney, or by personal service.