William F. Hubbard Jr., 55, a partner since 1971 in the engineering and surveying firm of Hoffman & Hubbard Inc. and an engineer in the Washington area for more than 30 years, died of cancer Monday at his home in Rockville.

Mr. Hubbard began his career in 1950 as a design engineer with the Washington Suburban Sanitary Commission. From 1953 to 1956, he was a project engineer with the Seybolt and George Corp. He then joined David Volkert Associates, where he rose to vice president before becoming a partner in Hoffman & Hubbard.

Mr. Hubbard was born in Cambridge, Md., and was a 1950 graduate of the University of Maryland. He served with the Army in Europe and the South Pacific during World War II.

He was a member of the Maryland Society of Engineers and the Suburban Maryland Home Builders Association. He also was a member of the Bethesda Country Club and the Potomac Presbyterian Church.

His marriage to Dorothy Ewell ended in divorce.

Mr. Hubbard's survivors include his wife, Jean H. Hubbard of Rockville; three children by his first marriage, Jefferson E. and William F. III, and a daughter, Lisa Anne Hubbard, all of Silver Spring; two stepsons, Craig M. and Scott G. Lewis, both of Rockville, and a sister, Doris Windsor of Cambridge. A third stepson, Brett R. Lewis, died in April 1980.