Standard&Poor's Ratings Services assigned its 'SP-1+' short-term rating to Watertown, Mass.' BANs. Standard&Poor's also affirmed its 'AA' standard long-term rating and Standard&Poor's underlying rating (SPUR), and stable outlook, on the town's GO debt outstanding. The ratings reflect the town's: Good location, providing local residents with easy access to all of the Boston MSA's employment centers; High wealth and income levels; Strong, primarily residential property tax base growth; and Low debt burden. The town's share of the county retirement system's unfunded pension liability slightly offsets these factors. The town's full faith and credit pledge secures the new notes and bonds outstanding. The town has recently completed a $45 million renovation at six of its public