SEATTLE — The U.S. Environmental Protection Agency is following through on its promise to propose a new clean-water rule for Washington, in case the state doesn’t come up with its own plan in time.

The EPA plans to officially publish its proposed rule in mid-September for public review. It posted details on its website Wednesday.

“Our preference is to work with states and have them develop standards that are protective,” said Daniel Opalski, who heads the EPA’s regional office of water, based in Seattle. The agency would halt its process “if the state comes forward and proposes something,” he added.

It would take between 8 and 11 months for the EPA to finalize standards for Washington, putting pressure on the state to act during that time, Opalski said.

The issue has been a contentious one. Tribes and environmental groups have argued for much stricter rules, while cities, counties and businesses say the technology isn’t available to meet stricter rules and that it could cost billions with little or no benefit to the environment.

In early August, the state Department of Ecology was on track to adopt a major rewrite of the state’s clean water rules, often referred to as the “fish consumption rule,” after years of debate and input from numerous groups.

But Gov. Jay Inslee put the rule on hold and directed the state Department of Ecology to reassess its approach. He said lawmakers didn’t pass legislation that he said was essential to tackling water pollution from everyday sources.

Under federal law, rivers and other water bodies must be clean enough so people can safely eat fish from those waters. Since 1992, the state has assumed that people consume about 6.5 grams of fish a day, roughly one small fillet a month.

The EPA is proposing to dramatically raising the fish consumption rate to 175 grams a day — similar to what Inslee had proposed a year ago. A higher rate theoretically would mean fewer toxic chemicals would be allowed and tougher permitting rules for facilities that discharge pollutants into state waters.

Federal regulators, however, left alone what’s known as the cancer-risk rate — one of many factors in a complicated formula to determine how clean state waters should be. It has been a point of contention. Tribes and environmental groups had pushed to leave it as is.

Inslee’s plan had lowered the acceptable cancer risk rate from eating fish from Washington waters from one case in a million to one case per 100,000 — a position supported by some businesses.

The national standard for fish consumption rate is 22 grams a day. Native Americans and Pacific Islanders in the Pacific Northwest consume much higher amounts of fish than elsewhere, and there are unique circumstances here that support a 175 grams a day rate, the EPA’s Opalski said.

“By protecting the highest fish consumer, you’re protecting everybody,” Opalski said.

Angela Chung, a manager with the EPA’s water quality standards, said it’s rare for the EPA to step in to impose a water quality standard for a state, but it has happened once before in Florida. In that case, the state ultimately submitted its own standards, she said.