Standard&Poor's Ratings Services affirmed its 'A+' underlying rating (SPUR) on McKinleyville Union School District, Calif.'s general obligation (GO) debt. The outlook is stable. The rating reflects our opinion of the district's: Record of maintaining very strong available balances, which we anticipate will continue; and Low overall debt burden. Partly offsetting the above strengths, in our view, is the district's slow debt amortization. Revenue from unlimited ad valorem taxes levied on taxable property in the district secures the GO bonds. The county board of supervisors has the power and obligation to levy these taxes for bond repayment at the district's request. The county is required to deposit such taxes, when collected, into the bonds' debt service fund. The district