SOUTH CAROLINIANS have worked hard in recent years to clean up all the trash that is strewn along our highways, even going so far as to create a state “litter czar,” as part of an effort to make our state more attractive to visitors and residents alike.

But the litter on the side of the road isn’t the only thing that mars the scenery: South Carolina has more billboards per mile than any other state. And some legislators are determined to make sure we retain that dubious title.

Again this year, billboard companies are backing legislation that would quash local governments’ nascent efforts to rein in billboards.

Cities and counties that restrict where billboards can be placed already have to give owners several years to remove existing signs — enough time to recoup their costs, and make a profit. As a result, most communities, like ours, already let existing billboards stay in place.

A bill that goes before the House Labor, Commerce and Industry Committee Tuesday would pretty much guarantee that this never changes. It would force local governments to pay outrageous levels of compensation to billboard owners if their signs are removed. The S.C. Municipal Association estimates the cost could be as high as $300,000 to $400,000 per billboard.

Even if you buy the argument that the government should have to shell out cash to close down billboards, the formula billboard owners are proposing is ridiculous. When the state Department of Transportation removes billboards to make way for road construction, it pays the owners, based on the cost of the billboard itself. The bill in the House — which specifically exempts the Transportation Department — would require cities and counties not only to pay the cost of the billboard, but also to pay what billboard owners would lose by not being able to rent out their billboard space, possibly for as much as 20 years.

That proposal is even worse than it sounds, because billboard companies don’t pay property taxes based on how much money the signs generate; they are taxed based on their capital outlay, minus depreciation. Municipal officials go so far as to say that they would be willing to reimburse billboard owners, based on the taxable value of their billboards. That could mean using the current “cost minus depreciation method” for both, or changing the taxing method to the “value of use” formula, and also using that to reimburse owners for any signs that are forced down. But two years ago, billboard companies rejected the first offer; we doubt they’d be any more receptive to the other one.

Even if the companies did agree, though, the Legislature shouldn’t approve either compromise; it should simply drop this whole idea.

In the first place, we see no reason to change the current method of letting owners keep their outlawed billboards up long enough to recoup their costs. Sex clubs, mobile home parks and junkyards don’t get reimbursed when they’re zoned out of existence. There’s even less reason to reimburse billboards, which have no independent value: They would be worthless if it weren’t for government-built and -maintained roads.

Beyond that, whether or how communities reimburse billboard companies, or any other business that is adversely affected by zoning decisions, is a purely local decision. As such, it should be made by local officials. The Legislature has no business interfering.