Workers repainted and refurbished the Tennessee American Water stand pipe on Missionary Ridge as part of the utility's ongoing maintenance of its water system.
The tank on the ridge, erected in 1924, is being changed from blue to white because tests have shown that white tanks hold their color longer and don't fade as quickly, company spokeswoman Daphne L. Kirksey said.
The paint is being applied to the inside and out to provide greater protection to the structural steel of the tank.
A similar repainting was recently completed at the 56-year-old South End tank on Bedford Avenue off of Central Avenue.
Tennessee American operates more than 20 tanks across Chattanooga to help maintain water pressure throughout its service territory.