he waterway toll bill finally became a waterway toll act yesterday, but not before one final snarl - this one involving a political squabble over bingo games - raised last-minute doubts about its fate.

After some hasty negotiating resolved the bingo problem, the House voted 287 to 123 to enact the bill, which would impose a federal tax on barge lines hauling freight on inland waterways that are built or maintained with federal funds.

The bill passed by the House is identical to the version the Senate approved Tuesday night. Thus it becomes an act of Congress without the necessity of a conference between the two Houses.

The act, in turn, seems certain to become law within the next two weeks. The Carter administration - as its contribution to a compromise that broke a long statement over the legislation - agreed late last week to sign the latest version.

Although the waterway charge contained in the act that passed yesterday is considerably watered down from the one Sen. Pete V. Domenici (R.-N.M.) had in mind 21 months ago when he introduced his original waterway bill, S. 970, yesterday's vote still constitutes a significant landmark in federal transportation policy.

The principle contained in the new act - that shippers must pay for use of federally maintained waterways - reverses a policy that dates back to the Northwest Ordinance of 1787, which declared that inland waterways should be "forever free . . . without any tax, impost, or duty therefor."

Despite its historical significance, the waterway bill ended its circuitous path through Congress hitched somewhat ingloriously to an obscure measure exempting certian bingo games from federal taxation.

The bingo gambit was the work of Sen. Russell Lond (D-La.), who dug out the bingo bill Tuesday to serve as a vehicle for th compromise package of waterway legislation that had been negotiated by congressional staff aides in meetings with lobbyists from the administration, the barge lines, the railroad industry and environmental groups.

Without a convenient vehicle like the bingo measure, the compromise never would have emerged from the crush of business that had accumulated as the 95th congress ground to a close.

Yesterday, however, the bingo measure became a cause celebre in its own right, and almost blocked passage of the waterway toll.

When Long introduced the waterway compromise in the Senate Tuesday, he worded it in such a way that the waterway legislation became a substitute to the bingo tax bill rather than an amendment to it. As a result, the "bingo bill" that emerged from the Senate contained the waterway compromise, all right, but lacked the bingo tax exemption.

This outraged some Democratic House members from Michigan, where the state party has used bingo games to raise campaign funds. They threatened to block the waterway bill unless the bingo language were reinstated.

That was not palatable to Sen. Robert Griffin, a Michigan Republican, who feared that the bingo revenues might be used against him in his race for reelection.

A flurry of last-minute lobbying pressure was brought to bear on all parties to the bingo battle, however, and they agreed to let the waterway bill move on to enactment minus any mention of bingo taxes.