Overcrowding in several Harvard Houses is reducing the number of "senior singles"--individual suites that contain both a living room and bedroom--offered to seniors each year, according to a survey of house secretaries yesterday.

This year only four Houses--Lowell, Kirkland, Adams and Quincy--are offering rising seniors the option of applying for such suites.

Most of the other River Houses, although originally built to include senior singles, have since decided to eliminate this housing option. The Quad Houses were designed to contain mainly one-room singles and doubles.

Bruce Collier, assistant dean of the College for housing, said yesterday that the decision whether to offer senior singles is "a policy decision that each House has to face on its own."

Collier compared Dunster House, which elminated the option last year, to Lowell House, which still offers 47 senior singles, to illustrate that Houses which are similar architecturally may have different housing policies.

Paul S. Goodof '71, assistant senior tutor of Eliot House, said yesterday that the Eliot House policy is to refrain from offering senior singles, because they place an unfair burden on sophomores and juniors.

"What else can you do, given the overcrowding situation?" Goodof said.

Sheila B. Schimmel, Lowell House secretary, yesterday said she anticipates a "drastic reduction" in the number of senior singles that will be offered to members of the Class of 1978.

The increase in the number of seniors in that class will force Lowell to convert many of its senior singles into doubles, Schimmel said.