A refinancing effort approve Monday by the city council should save ratepayers millions of dollars over the next three decades.

King County sold $500 million of sewer revenue bonds on Sept. 12. The transaction raised $50 million of new funding for its capital program at a 3.8 percent interest rate, and also refinanced outstanding bonds to reduce future debt service costs. The refinancing will save ratepayers $104 million over the next 33 years.

King County’s wastewater utility funds much of its capital improvement program by selling sewer revenue bonds. The money borrowed is paid back through current and future monthly sewer rates and charges.

“This bond sale shows the value of King County’s strong, disciplined financial management,” said Executive Dow Constantine. “Our excellent credit means we pay less interest, and that means ratepayers save money. All the while we can continue to upgrade and expand vital infrastructure to help clean up our rivers, lakes and Puget Sound.”

Strong bond ratings help the County secure lower interest rates on the bonds it sells. Last month, Moody’s and Standard & Poor’s affirmed their respective ratings of the utility’s sewer revenue bonds at Aa2 (positive outlook) and AA+ (stable outlook), citing the utility’s strong management practices, consistent financial performance and the region’s bright regional economic outlook.

Since 2009, the County has re-financed 14 times for a total debt service savings of $514 million.

Additional information about the utility, its service mission and its finances is available online at http://www.kingcounty.gov/ratepayerreport.