(a) In the case of a review by the state board under Section 13320, the state board, upon notice and hearing, if a hearing is requested, may stay in whole or in part the effect of the decision and order of a regional board or of the state board.
(b) If a petition is filed with the superior court to review a decision of the state board, any stay in effect at the time of the filing the petition shall remain in effect by operation of law for a period of 20 days from the date of the filing of that petition.
(c) If the superior court grants a stay pursuant to a petition for review of a decision of the state board denying a request for a stay with respect to waste discharge requirements, the stay may be made effective as of the effective date of the waste discharge requirements.