Only a quarter of the women raising children alone are receiving child-support payments from absent fathers, the Census Bureau reported yesterday.

Using surveys of family status in 1975, the report shows that 1.3 million divorced, separated, remarried or never-married mothers received child support from the fathers of their children, averaging $2,430 a family. The 1.3 million figure represents a quarter of all such mothers.

The report said the mothers most likely to receive some child support from absent fathers were divorcees and well-educated women.

About 40-percent of divorced mothers receive child-support payments, but only 4 percent of the never-married mothers get child support. Mothers who don't get child support have a higher poverty rate. Many subsist on welfare.

Mothers who are college graduates receive payments more frequently [45 percent of the time] and at a higher rate [$5,290 a year on the average] than high school or elementary school graduates. While mothers also do better than minority mothers.

The report also showed that relatively few women receive alimony --in 1975, only 4 percent of 4.5 million divorced or separated women got alimony.

Another Census Bureau reports shows that the number of women maintaining families without a husband present has skyrocketed -- up 44 percent from 1970 to 1978, when it reached eight million. The biggest increase is in single black women with families up to 184 percent from 1970 to 1978.

Despite these trends, the vast majority of children under 18 still living traditional families with both parents present -- 81 percent in 1978. The figure is dropping gradually however in 1970 it was 88 percent and in 1960 it was 91 percent.