The Biden administration is rolling back another Republican gift to polluters with an Environmental Protection Agency announcement that the Trump administration’s repeal of the Waters of the United States rule, crafted during the Obama administration, will itself be undone so that a new version of the rule can be crafted. This was expected; actually crafting a new version, though, will be the hard part.

In a New York Times report, however, EPA administrator Michael Regan suggests that a return to the exact Obama-era rule is unlikely. Instead, newly developed rules will take from “the lessons learned” by both the Obama and Trump versions.

The heart of the issue is a long-running battle over just what ought to count as the “waters” of the United States, when it comes to providing the anti-pollution protections of the Clean Water Act. The Obama administration’s rule greatly broadened the scope of the act by including wetlands, streams, and other small waterways that had previously gone unprotected. This meant that polluters leaking fertilizers or other toxins into small streams, including streams that might flow only during wet months but not try ones, could be held to account using the Clean Water Act that already protects the larger bodies of water they flow into. It was a logical move; restrictions on the dumping of toxic material into the national water supply are considerably weakened if polluters can simply do the dumping farther upstream, in places where the rules do not apply.

The new rules were absolutely hated by farm bureaus and other agricultural lobbyists. By broadly expanding the range of anti-pollution regulations to include even seasonal wetlands and the like, considerable new portions of their membership suddenly found themselves subjected to rules prohibiting the runoff of fertilizer and agricultural chemicals used in nearby fields. Conservative farming communities, in particular, lost their minds over what has previously been seen as a God-given right to pollute in their own personal neighborhoods.

Developers were similarly up in arms. Anyone who has seen a modern housing development being constructed can attest that the usual method starts with a large-scale reshaping of the land that flattens each hill and either fills gullies or redirects them into concrete channels or underground pipes. If seasonal creeks could no longer be paved over or turned into storm drains for draining the new development’s streets, megadevelopments of the sort preferred by the largest development companies would suddenly require far more expensive designs.

Trump’s team scrubbed the rule in 2019, instead formulating a new one focused only on protecting “navigable” waters. The short version might be “if you can’t put a boat in it, it doesn’t count,” and Trump’s conservatives thus nullified the majority of the new protections.

The Biden EPA now finds itself searching for a new version that will restore most of those protections—because, again, agricultural and development runoff is responsible for massive amounts of pollution, a problem both for drinking water supplies downstream and one that threatens the major waterways that are inarguably protected by the Clean Water Act—while possibly coming to a compromise position that does not result in agricultural lobbyists erupting over the existential threat caused by having to block fertilizers from entering nearby waterways, or development lobbyists declaring that our very way of life is threatened if bulldozers have to choose more delicate paths around natural features.

This may well be impossible, of course. If the metric is simply one of keeping prohibited toxins out of natural waterways and local drinking supplies, it seems possible that a common definition could be reached. Once you start getting into the “right” of property owners to erase streams from existence or redirect water from new streets and lawns into whatever culverts can least expensively make it someone else’s problem, things get dicier.