W.C. (Bud) Dutton Jr., head of the Prince George's County Planning Board, has bought a $155,000 house with 10 acres on the Patuxent River immediately adjoining one of the parks his agency operates.

Dutton has access to his home, to which he moved last month, by two roads, one of which is owned and maintained by the Maryland National Capital Park and Planning Commission.

His property includes a small piece of river-front marsh that would be acquired as part of the proposed Patuxent Scenic River Park, a controversial proposal now undergoing major changes. Another part of his property would be eligible for a scenic easement, under which he would receive a tax reduction in return for promising not to build on it or for permitting some kind of public access.

With the planning staff moving this year from Riverdale to the new county office building in Upper Marlboro, Dutton said yesterday he and his wife decided in December, 1975, to look on for a home on eh Patuxent.

He began negotiating last August for the 62-year-old frame house on a hill overlooking the river. The park and planning commission road leading to the Mount Calvert Park at Jug Bay was already there at the time.

Dutton said he checked several maps to determine how the property could be affected by various versions of the Petuxent park plan. "It would be obviously an untenable position if the (planning) chairman was going to buy inside the park line," he said. "But we're operating under such financial constraints it's unlikely the land will be purchased during the time when I'm on the commission."

Dutton said he was "aware of the potential embarrassment" in acquiring the property "although I came in with my eyes open . . . I expect to live in that area and be a good neighbor," he said.

The gray-haired Dutton has been with the planning agency since 1966, and receives $35,000 a year as its fulltime head. His wife, Frances, is director of the Office of Supportive Servicies for the State Division of the Aging in Prince George's County.