The prohibition shall not apply to any non-storm water discharge
permitted under an NPDES permit, waiver, or waste discharge order
issued to the discharger and administered under the authority of the
Federal Environmental Protection Agency, provided that the discharger
is in full compliance with all requirements of the permit, waiver,
or order and other applicable laws and regulations, and provided that
written approval has been granted for any discharge to the storm sewer
system.