SAN FRANCISCO (S&P Global Ratings) Oct. 30, 2018--S&P Global Ratings assigned its 'AA+' long-term rating to Tacoma, Wash.'s series 2018 sewer revenue bonds. At the same time, S&P Global Ratings affirmed its 'AA+' long-term and underlying rating on the city's sewer system's existing debt. The outlook is stable. "The rating reflects our view of the sewer system's very strong enterprise risk and extremely strong financial risk profiles," said S&P Global Ratings credit analyst Chloe Weil. The very strong enterprise risk profile reflects our view of the sewer system's: Service area participation in the broad and diverse Seattle-Tacoma-Bellevue metropolitan area economy; Sewer rates that remain relatively affordable, even as management has implemented moderately large (on a percentage-change basis) annual rate adjustments