Standard&Poor's Ratings Services has raised its ratings on Trinity River Authority, Texas' wastewater system revenue bonds and general improvement revenue bonds to 'AAA' from 'AA+', primarily reflecting the member cities' improving general creditworthiness and financial stability, as well as their strong service area economies and the strong operations of the respective utility systems. The authority's series 2009 central regional wastewater system project bonds(Texas Water Development Board clean water state revolving fund loan) have been rated 'AAA'. The participant cities'' water and sewer systems collectively exhibit: Margins that are able to generate sound coverage of all on-balance-sheet and off-balance-sheet obligations, including those to the authority; Strong liquidity; and Moderate retail service rates, coupled with a demonstrated willingness to adjust