The Washington Suburban Sanitary Commission selected yesterday the former secretary of the Maryland Department of Natural Resources to manage the giant water and sewer utility for Montgomery and Prince George's counties.

John R. Griffin, 53, who has political and personal ties to both counties, will become general manager after a nearly year-long national search failed to produce a job candidate acceptable to representatives of the two counties.

Griffin grew up in Rockville and worked for the Prince George's County Council in the 1970s. He assumes the top administrative post at a time when county and state officials are deciding whether the utility should be sold to a private operator.

Griffin said he is open to the idea of privatization. But he said the issue was "beyond WSSC as an institution."

A task force studying whether WSSC should be sold concluded its deliberations this month without making a formal recommendation.

Griffin applied for the job this summer after the commission--comprising three commissioners from each county--deadlocked on a successor to Cortez A. White, who retired in June. White cited differences with Prince George's County officials for his departure.

Prince George's County Executive Wayne K. Curry (D) and Montgomery County Executive Douglas M. Duncan (D) both backed Griffin for the job.

Curry called Griffin an "even-keeled, conscientious manager."

"I think it's fortuitous his career circumstances made him available at a time this decision was made," Curry said.

Griffin said his 30 years of political experience would help him smooth relationships between the counties and the utility, a quasi-public agency that answers to two county councils, two county executives, the state legislature and 1.6 million customers.

"Perhaps I bring at the beginning a little more seasoning in understanding the political world in which this institution operates," said Griffin, who served as a Cabinet official under Gov. Parris N. Glendening (D) for 4 1/2 years. He has been working as a consultant to Rep. Wayne T. Gilchrest (R-Md.) since this summer.

Commissioners from both counties said yesterday that the support from the two executives and Griffin's political connections made him a unanimous choice for the $140,000 position. Griffin signed a three-year contract.

"He knows all of the players, and he has their trust," said WSSC Commissioner Kevin P. Maloney, who represents Montgomery County. "We felt he'd be fair."

Duane W. Oates, who represents Prince George's on the commission, said Griffin also seemed committed to diversity--a priority for leaders from his jurisdiction.

Griffin takes over Oct. 18.

CAPTION: John R. Griffin was named general manager of the Washington Suburban Sanitary Commission.