For many students, the road to a college education is paved with loans. The situation has gotten badly out of hand.

As the cost of going to college has escalated, so has dependence on federally-guaranteed student loans. Nearly four-million students will receive more than $9.5 billion in such loans during fiscal 1989.The problem is not so much with the loans as it is with the disturbing increase in the number of students who can't or won't repay them. Congressional Quarterly reports that defaults on the loans will cost the government an estimated $1.6 billion this year and as much as $2 billion by 1990.

Such losses simply cannot be tolerated under any circumstances, let alone at a time Washington is struggling to reduce and eventually eliminate the staggering federal deficit.

What's to be done about it?

Already, Washington is going to get tough on schools with unusually high rates of student defaults, either suspending the schools or dropping them altogether from the federal loan programs.

Also under consideration is a plan to crack down on fly-by-night trade schools and third-rate colleges that lure ill-prepared students to enroll and then, when the students drop out, keep the federal-aid money.

But such steps aren't nearly enough. There's still no substitute for tightening up on eligibility requirements and reappraising the basic principles of the federal loan programs.

Though these programs began as a supplement for middle-income students, Congress changed the law so much that now any student who can demonstrate the need for help in meeting college costs is eligible to borrow money under the guaranteed student-loan program.

Clearly, Washington needs to do more than just get tough on the dead-beats. It also needs to get tough on those who extend loans to students with little prospect of repaying them - which means that Washington needs to get tough on itself.