After receiving notice pursuant to subdivision (b) of Section 6958, the affected regional water quality control board shall review the proposed formation and report its findings in writing to the board of directors of the public agency. The report shall specify the maximum number, type, volume, and location of on-site wastewater disposal systems which could be operated within the proposed zone without individually or collectively, directly or indirectly, resulting in a pollution or nuisance, or adversely affecting water quality. The regional water quality control board may require from the public agency such information as may be reasonably necessary to make the findings required in this section.