The San Diego County Water Authority’s senior lien credit rating was upgraded to AAA by S&P Global Ratings. Water authority officials say Wednesday’s one-notch upgrade marks the first time it has achieved a triple-A rating. The authority, in a news release, called the upgrade “a boon for ratepayers who will benefit from lower financing costs.” S&P credited the upgrade to strong financial management, robust drought planning, increased storage capacity due to the San Vicente Dam Raise, and reserves for managing contingencies, among other factors.