The government proposed new rules Thursday that require factory-style farms to obtain permits and set conditions when polluting rivers, streams and lakes with animal waste.

The proposed rules from the Environmental Protection Agency would require owners and operators to apply for a permit before polluting and to attach a nutrient management plan. EPA officials also would give the public a chance to comment on it.

But the rule also would allow the farm businesses to define what constitutes pollution, and it would exempt them from needing a permit if they discharge only agricultural stormwater.

EPA's proposal is a revision of rules from three years ago. The 2nd U.S. Circuit Court of Appeals in Manhattan ruled last year that those regulations weren't adequately protecting the nation's waters from the manure produced by large farms.

In response to a lawsuit brought by a New York-based environmental group, Waterkeeper Alliance, the court said that the rules had failed to result in any meaningful review of plans developed by the farms to limit the pollution.

The rules are intended for the nation's 18,800 concentrated animal-feeding operations, which contribute up to 60 percent of all the manure generated by farms that confine animals, according to EPA.