Amounts of Rates and Charges; Refunds

Except to the extent otherwise permitted or required by an indenture or any contract relating to indebtedness issued by the Authority, all rates and charges shall at all times be fixed to yield annual revenues at least equal to

(a)the annual principal payments and interest charges and reserve fund requirements on all bonds at any time issued and outstanding hereunder,

(b)the annual system operation and maintenance costs, and

(c)the annual principal payments and interest charges on all other outstanding indebtedness issued by the Authority. An indenture or contract of indebtedness may provide for payment from revenues of refunds of rates and charges that are collected in error and that are refundable by the Authority.