The City Council on Tuesday placed Quincey on indefinite paid leave of absence during a closed session meeting.
Quincey was elected to the San Antonio board in April 2010. His role may soon change as a new board will be nominated in February and voted on at the annual meeting of shareholders in April, said Charles Moorrees, San Antonio general manager.
"By February there will be a new slate of officials that are going to be present for the annual meeting in April, so it can be changed shortly, I guess," Moorrees said.
Quincey has not returned calls for comment.
The City Council made the decision unanimously Tuesday to place Quincey on leave, but members would not state the reasons for the action.
It was reported in December that Quincey had negotiated a $25,000 settlement of a police sergeant's lawsuit alleging he was passed over for a promotion because he had investigated a domestic incident involving Quincey.
The sergeant was promoted to lieutenant as part of the settlement.
Being the majority shareholder in the company, the city of Upland will submit a slate of officers to be on the board at the annual shareholders meeting.
Other nominations can be submitted at the meeting, which hasn't happened in a while, Moorrees said.
"I know one time there was some other slate that got rejected. The city didn't accept those nominations," he said. "It happened, but recognizing that the city is the majority shareholder, the vote's going to tend to go that way."
Quincey is the second board member whose position with the city has recently changed.
Board President Tom Thomas on Nov. 2 lost re-election to the council, but is able to remain on the board if renominated by the city.
"I hate to see these things going on," Moorrees said. "I like having a stable board. You get a lot of things done when you've got a unified board that works together."
For more than 125 years, the San Antonio Water has provided water service to its shareholders, who include residents in Ontario, San Antonio Heights and Upland.