When Ronald Reagan brings his new budget balancing team to town in January looking for waste and fraud to cut from federal programs, he also might want to consider collecting some of what's already owed the government -- a staggering $175 billion.

A special project team at the Office of Management and Budget has been trying for the last 15 months to add up all the figures of outstanding federal loans, delinquent taxes and overpayments to Social Security and other grant recipients.

About $150 billion of the total is in loans, many of which are long-term and being paid off on time. But the OMB figures also show tht $47 billion of the debt came due in the fiscal year that ended Sept. 30 and more than half of it was delinquent.

That's a tidy sum of $25 billion that the government wouldn't or couldn't collect. The biggest chunk of the overdue debt is owed to the Internal Revenue Service: $13.3 billion at the end of September 1979, and $15.8 billion now, according to updated IRS figures.

What's the problem? A recent Senate Appropriations Committee report put much of the blame on federal program managers. "It appears that agency officials often think their only role is to hand out federal money, rather than collecting it when it is due," it said.

In an interim report last spring, OMB debt collection project manager Jerry Bridges noted ruefully that his team was having trouble compiling figures because agencies did not have adequate records, systems or staffing to even calculate what they were owed by borrowers, much less collect it. "Most agencies cannot improve their collection efforts until they allocate more resources," he wrote.

For instance, he said that at the Law Enforcement Assistance Adminstration, only four full-time and two part-time employes were assigned to service 210,000 student loan accounts totaling $150 million. The State Department had only one employe servicing 3,000 accounts for almost $100 million in loans from organizations and receivables from individuals and contractors.

There is little incentive for program managers to collect debts because the recovered funds often go to the Treasury, not the specific agency, and losses are restored by appropriations, Bridges added.

The Appropriations committees have started making threats about budget cuts to offset uncollected debts, but immediate solutions are hard to come by.

Attempts to get IRS to offset delinquent debts against future tax refunds have been defeated. Only a few agencies are permitted to report delinquent debtors' names to credit bureaus.

In his interim report, Bridges said "contracting out the accounting and servicing of receivables may be a viable alternative to explore, at least in the interim until the larger financial systems are fully developed and operational."

No one realistically expects that government agencies will be able to collect as great a percentage of its debts as private industry. Federal loans, whether to Chrysler or a low-income family for a home, are by definition social programs that carry greater risks of default. But it seems clear even from OMB's preliminary work that a lot more can be done.

This week the Senate Governmental Affairs Committee will hold hearings on the debt collection problem in support of a bill sponsored by Sens. Charles H. Percy (R-Ill.) and James Sasser (D-Tenn.) to report all delinquent debtors to credit bureaus.

A Percy aide has collected horror stories of failures in some collections programs. Student loan programs in general have been notorious for defaults, with about $2.2 billion owed currently. But the committee found how one successful program, for Cuban students, disintegrated when its collections staff was shifted elsewhere in 1976.

At the time, the pay-back rate was esceptional, with less than $1 million of $34 million delinquent. But then the staff was shifted and the loan records shipped to a different office where they sat in boxes. Now more than $20 million is delinquent.

One LEAA program handed out $278 million in loans to individuals who could get the debts forgiven if they served four years in the field. When LEAA sent out forms asking the 312,000 recipients to certify their law enforcement employment or pay up, only 16 percent responded. The GAO found only $5 million has been collected to date.

A continuing problem in debt collection has been the inadequacy of staff to ensure compliance. The GAO learned recently that 56 people at the Department of Housing and Urban Development were trying to manually police 55,000 delinquent loan accounts in the billion-dollar-a-year Title I rehabilitation program.

The HUD program had no way to prevent individuals who had defaulted one loan from applying for and getting another, the Percy aide discovered.

While IRS is given high marks for its computerized collections systems by OMB, it has run into some of the same manpower problems. In a move that Treasury Department officials and congressional critics have called "penny wise and pound foolish," there actually have been cuts in recent years in the manpower levels of the main revenue-producing agency.

For instance, between fiscal 1975 and 1979, the 12,000 staff-years devoted to collecting delinquent accounts was cut by nearly 10 percent, according to Robert Starkey, assistant commissioner for compliance.

IRS officials also cite other factors for the soaring delinquency rate -- double what it was five years ago. Until early this year, delinquent accounts were assessed only 7 percent interest, hardly an incentive to pay. And, Starkey said, the gloomy economy in recent years simply had added to the numbers of people who are hard pressed to pay what they owe Uncle Sam.

Of course, some of what the IRS claims it is owed is disputed in Tax Court, uncollectable because of bankruptcies, or simply deferred because the amount due is too small to chase. A year ago, for instance, IRS listed only $2.9 billion as being "actively" pursued. More than $4 billion in overdue taxes was still in the "notice" stage of dunning letters. Another $2.3 billion was set aside because of litigation or further investigation and $3.3 billion was listed as uncollectable.

The latest figures show $3.6 billion of the total $15.8 billion overdue to be in the "active" file, Starkey said. Individuals owe about one-third, businesses the rest.

Unlike the other agencies that place a low priority on collections, IRS and Treasury Department officials have been yelling for years at OMB to give it more manpower so it can collect more revenue.

The House government operations subcommittee chaired by Rep. Benjamin Rosenthal (D-N.Y.) showed at a hearing last month that the warnings usually were ignored. Memos to budget officals protested as "counterproductive" and "shortsighted" for the Carter administration's efforts to restrict IRS staffing.

Dr. John White, deputy director of OMB, said Friday that IRS's ability to produce revenue is taken seriously. "They do better than the run-of-the-mill bureaucrat," he said.