The ratings agency Standard & Poor's Financial Services raised its rating on Colleyville's water and sewer system revenue refunding bonds to AAA in late-March, reflecting the system's stability and low debt level, according to the S&P report.

City spokeswoman Mona Gandy said S&P typically reaffirms or upgrades bond ratings every two to three years and had already rated Colleyville's general obligation and drainage utility bonds as AAA, the highest available bond rating.

"Achieving a third AAA rating is a testament to the hard work by city leadership and staff to manage our projects and budgets effectively," Mayor David Kelly said in a news release. "It allows us to do more with our tax dollars, and that's good for Colleyville citizens and businesses."

The report said the bond was raised from AA+ as a result of a stable, long-term water supply that requires moderate water and sewer rates and adds limited capital needs.

For Colleyville, this means it can borrow money at lower interest rates when issuing debt, or refinancing existing debt, for city capital projects, which saves money for the taxpayer, Gandy said.

S&P's report projects that the city's water and sewer systems debt level of $2.1 million in revenue bonds will be paid off by 2018.