S&P Global Ratings has assigned its 'AA-' long-term rating to Dayton, Ohio's series 2018 water system revenue bonds. S&P Global Ratings also affirmed its 'AA-' long-term rating on the city's existing water system revenue bonds. The outlook is stable. The rating reflects, in our opinion, the combination of the water system's strong enterprise risk profile and its extremely strong financial risk profile. The enterprise risk profile reflects our view of the water system's: Service area participation in the broad and diverse Dayton metropolitan statistical area economy; Very low industry risk as a monopolistic service provider of an essential public utility; Rate affordability that we consider average when benchmarked against the county's median household effective buying income (MHHEBI) and poverty rate