NAPA COUNTY – Standard & Poor’s has assigned a AA credit rating to Napa County’s 2012 Certificates of Participation, a move that will help the county obtain lower interest rates when it markets those certificates in the near future.

The issue, expected to begin this week, is meant to take advantage of a currently low interest rate environment to refinance a 2003 certificate issue. Refinancing those certificates, which paid for the construction of the sheriff’s office on Airport Boulevard and the Juvenile Justice Center in Napa, is expected to save the county $1.5 million in interest payments over the 20-year obligation, according to a release from the county.

S&P’s rating committee applied the AA rating due to Napa County’s low debt ratios and general fund growth through the economic downturn, according to KNN Public Finance, the county’s financial adviser. The county’s general obligation issuer rating remained at AA+, with the highest possible rating being AAA+.

“Once again, we are seeing the benefits of our conservative fiscal practices,” said Napa Board of Supervisors Chairman Keith Caldwell, in a written release.

The county’s financial adviser will continue a dialogue with S&P about a possible future upgrade to the general obligation rating, according to the release.