Standard&Poor's Ratings Services assigned its 'AA' long-term rating, and stable outlook, to the town of Watertown, Mass.' GO bonds. Standard&Poor's also assigned its 'SP-1+' short-term rating to the town's BANs. 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-to-moderate 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 bonds and notes. Watertown, with a population of 32,986, is a fully developed suburban community bordering Boston, Mass. The town's location is desirable; located just