Loan terms shall include, but not be limited to, the following:
(1) The term of the loan shall not exceed twenty years, except for systems serving disadvantaged communities which term may not exceed thirty years;
(2) The interest rate shall be at or below market interest rates;
(3) The annual principal and interest payment shall commence not later than one year after completion of any project; and
(4) The loan recipient shall immediately repay any loan when a grant has been received which covers costs provided for by such loan.