Three members of the District of Columbia School Board, including its president, Dr. Therman Evans, have decided not to run again in the Nov. 8 election.

Besides Evans, a 33-year-old physician who said he might be interested in running for mayor or City Council chariman next year, the other two board members who have announced that they will not seek re-election are Julius W. Hobson Jr. (ward eight) and William Treanor (ward two).

Hobson, 29, said his main reason for not seeking a second term was financial.

"Being on the school board is almost equivalent to a full-time job," said Hobson, who works as an editorial assistant at Howard University's Institute for the Study of Educational Policy. "The $4,000 we get a year just doesn't cover it. I simply can't afford to continue."

Treanor, 33, has been away from Washington since Aug. 10 on vacation, and is not due back in the city until after Labor Day. Before he left, he said he would not seek re-election because serving on the school board had often become burdensome and unsatisfying.

Treanor, executive director of the National youth Alternatives Project, said the only time since his election in 1973 that he had been the subject of a prominent news story was when he was arrested for disorderly conduct after getting into an argument with a policeman. When he was acquitted, Treanor said, the story got much smaller play.

Altogether, seven seats on the 11 members school board are up for election in November, including two, inwards four and seven whose elected members resigned during the past year and were replaced by appointees.

The two appointed members, Victoria T. Street (ward four) and Minnie S. Woodson (ward seven), both have filed nominating petitions, but so far only one elected member, Carol Schwartz (ward three) has done so.

The filing deadline is 5 P.m. today.

The other elected member whose term expires this year, Barbara Lett Simmons (at-large), said yesterday that she has not yet decided whether or not she will run, even though supporters have collected signatures for her, she said.

D.C. school board members are elected to four year terms.

Yesterday board president Evans said one reason he was not seeking re-election to his at-large seat in November is that if he decides to run for the City Council or for mayor> he would have to resign about six months later.

"A lot of people urged me to run for the school board again," Evans said. "And I think I would have no problem being re-elected. But I think it's time now for me to move on and give somebody else a chance on the school board."

Evans has served as school board president since January 1976 - the quietest period for the board since its members first were elected in 1968. Although he supported Barbara Sizemore, whom the board majority fired as superintendent in October, 1975, Evans has warmly praised the current city school superintendent, Vincent Reed.

"I feel we have done a decent job in bringing stability to the school system," Evans said yesterday, "in quieting things down, and getting school board members to address issues rather than each other."

While Evans has been president, most of the board's work has shifted from long, acrimonious meetings to quiet work sessions, and Reed has dominated policy-making more than any D.C. school superintendent since Carl Hansen, who left in 1967.

One factor leading to relative quiet on the school board has been the emergence of the D.C. City Council as the District's main political arena since Council members were first elected in 1974. Four former school board members have served on the elected Council, and two others were defeated trying to get on it.

Despite the calm, Hobson said he still often spends more than 30 hours a week on school board business - handling complaints from parents and teachers, attending civic meetings and ceremonies as well as school board sessions.

"People call you all times of the day or night," Hobson said, "and when you have enough interruptions, it does cause problems on your job."

"I think it's likely that board members will be older in average age," Hobson added. "Either they'll have to be retired or pretty well off."

Last October, former board member James S. Featherstone Jr. resigned his seat after having been unemployed for 10 months. Featherstone said the only job he could find was with the city government, and he could not keep it under D.C. conflict-of-interest laws if he remained a board member.