A COUPLE of months ago, we suggested that Congress should adopt a formal policy on what -- in the way of buildings, parks and so forth -- should be named after its former members. Since then, the thing has really gone out of control. It has been suggested on the House floor that sewage plants be named for retiring representatives.

Not so fast. Of course there are some cases where this would be supremely fitting. But not all of these people deserve to have their names emblazoned in sludge. The question is merely whether they deserve to have them emblazoned at all.

Congress thinks they do. During the last frenzied days before it recessed last week, more than a dozen of its members -- past as well as present -- won this badge of office. There will be, early next year, the Roy Roberts Lake in Texas and the William H. Harsha Lake and Dam in Ohio. These were previously Aubrey Lake and just plain old East Fork Lake and Dam. The post office and courthouse in Concord, N.H., will become the James C. Cleveland Federal Building. The federal building and courthouse in Amarillo, Tex., will become the J. Marvin Jones Federal Building (he left Congress in 1940). The list is too long, but you get the idea. Oh, yes, the big winner got a major piece of legislation named after him. It's the Harley O. Staggers Rail Act of 1980.

It was while one of these bills was on the House floor -- we won't say which one -- that the question of sewage plants came up. Rep. Elliott H. Levitas, this particular bill's floor manager, was asked whether there are enough buildings, lakes and dams to go around or whether it will become necessary to go into sanitary districts and water pipes.

"I can assure the gentleman that we have even considered the possibility of sewage-treatment plants as being an appropriate facility to name after certain individuals," Mr. Levitas replied, having a little fun.

But he and his colleagues on the Public Works Committee shouldn't brush off this sewage-plant idea so lightly. So honoring just one of these facilities and one of these estimable legislators might get rid of the crazy notion that anyone who survives a few years in Congress deserves a permanent memorial.