SAN FRANCISCO (Standard&Poor's) March 6, 2013--Standard&Poor's Ratings Services assigned its 'AA+' long-term rating to King County, Wash.'s $177 million series 2013 sewer revenue and refunding bonds, which are "parity," or senior, obligations of the county's sewer system. The outlook is stable. "The rating reflects our view of such factors as the county's consistent financial performance, the county sewer system's role as the sole regional provider of wastewater treatment services, maintenance of very strong designated cash reserves, and the county's robust economic base," said Standard&Poor's credit analyst Paul Dyson. The parity bonds are being issued by King County's sewer system, and the proceeds will be used to refund all or a portion of the county's