40 CFR 147.2921 - Schedule of compliance.
(a) Any schedule of compliance shall require compliance as soon as possible, and in no case later than three years after the effective date of the permit.
(1) The time between interim dates shall not exceed one year.
(2) If the time necessary for completion of any interim requirement is more than 1 year and is not readily divisible into stages for completion, the permit shall specify interim dates for the submission of reports of progress toward completion of the interim requirements and indicate a projected completion date.
(c) The permit shall be written to require that if a schedule of compliance is applicable, progress reports be submitted no later than 30 days following each interim date and the final date of compliance.