The legislative body may adopt a resolution determining that bonds shall be issued and assessments collected and enforced pursuant to Part 5 of this division. In such event, the notice to repair shall specify that bonds shall be issued to represent the security of the unpaid assessments, payable over a period of not to exceed six years, and shall further recite a maximum rate of interest to be paid on the indebtedness, which shall not exceed 7 percent a year, payable semiannually.