SAN FRANCISCO (Standard&Poor's) Oct. 16, 2012--Standard&Poor's Ratings Services revised its outlook to negative from stable on the East Bay Municipal Utility District (EBMUD), Calif.'s existing water system revenue bonds. At the same time, Standard&Poor's assigned its 'AAA' long-term rating to the district's approximately $205 million series 2012B and approximately $50 million series 2013A water system revenue bonds. Finally, Standard&Poor's affirmed its: 'AAA' long-term and underlying rating (SPUR) on the district's outstanding water system revenue bonds (the short-term ratings on the series 2008A variable rate demand bonds are based on the short term ratings of the standby bond purchase agreement providers); 'A-1+' short-term rating on the district's series 2009A-1 and series 2009A-2 water