When President Carter signed the higher education bill Oct. 3, lots of middle-class parents looked forward to a brand new program that would allow them to get low-interest government-guaranteed loans to send their kids to college.

The parent loans, up to $3,000 a year per student at 9 percent interest, are an entirely new feature in the guaranteed college-loan program, and are in addition to the $2,500 a year a dependent student can borrow on his or her own under the established guaranteed student loan program. The new parent-loan program is intended to help middle-class parents with all the bills that remain even after their son or daughter has taken out a student loan.

But parents had better not start counting the money yet.

Although the new program is supposed to go into effect Jan. 1, only one state, Massachusetts, appears ready to start making the parent loans available for the February college term.

In Maryland (and a number of other states), the new parent-loan program must get the okay of the state legislature and the program, as a result, isn't expected to start until next summer.

In both Virginia and the District of Columbia, agencies and banks participating in the current student-loan program say they don't expect to be making parent loans before next summer.

One reason, according to Eugene Cattie, executive director of the Virginia Education Loan Authority in Richmond, is that the U.S. Department of Education hasn't issued regulations spelling out detailed requirements governing the program, and isn't expected to do so until the end of this month.

As a result, Cattie said, banks that make the actual loans and have them guaranteed by state or special nonprofit agencies (with the federal government providing interest subsidies and reinsurance against defaults) are reluctant to get into the program. "Lenders are very hesitant to get into a program where the regulations are not defined yet. Lenders are hesitant to jump in," said Cattie in a telephone interview.

But even after they see and digest the regulations, banks and other lending institutions, as well as the state guarantee agencies, need time to draw up and print new contract forms and other papers for the parent loans, set up new procedures, computerize their parent loan systems and take care of other paper work and procedures, said Richard Hawk, president of the Higher Education Assistance Foundation, a nonprofit group that is the designated loan guarantor in six states and the District of Columbia.

"Assuming there were no clinkers in the regulations," said Hawk in a telephone interview from Kansas, one of the states where HEAF operates, "60 to 90 days after the regulations would be the earliest" the parent loan program could actually get started in the HEAF states. So if the regulations are available by Jan. 1, loans couldn't be made before the February term starts.

Hawk said if the federal regulations had been issued by Nov. 1, or about a month after the bill was signed, it might have been possible to start making loans for the February semester. He said that from one point of view, three months to write a regulation did seem a bit of a long time, but on the other hand, he added, "I have come to the conclusion from long experience that it simply takes the federal bureaucracy a fairly long time to do these things" and in that context three months really isn't so long. (Others pointed out that it took the Department of Health, Education and Welfare more than two years to issue final regulations for the 1976 student loan amendments, although loans were made anyhow.).

David Bayer, chief of the Guaranteed Student Loan Branch of the Department of Education, said final regulations are " in clearance" but it takes a long time to go through every word of the new law and set up rules on how it should be run. Cattie, agreeing on the difficulty, said it is a "very complicated law" that must be studied carefully before the regulations come out.

Bayer said he believes bank and state paper work and computerization requirements, rather than regulation delays, will be the primary reason most states won't get the program started by February.