John Carlson, the Arvada city worker who found the gold 1978 Pomona High School ring, took it home and meticulously cleaned it, KMGH-TV, Denver, reported Wednesday.
He then used the Reunion.com Web site to find the owner, Gerry Duran, who lives in Del Norte, Colo.
Duran's mother picked up her son's ring Tuesday and recalled how it was lost more than 25 years ago.
"Gerry was getting ready for school and was going to take a shower. He took his class ring off and he dropped it and had just flushed the toilet so it went down (with) the stool," said Duran's mother, Margie Johnson, who also praised Carlson and his fellow workers.
"I think it's remarkable," Johnson said. "You hear about employees going the extra mile. I can't imagine wanting to even clean a ring that's been in the sewer system for 28 years."