Last Friday, while the media focused on the thousands of protestors at Standing Rock, a construction crew working on the same under-protest project finished drilling through rock under the Des Moines River in Iowa–another major source of drinking water.

The pipeline crosses the river near the tiny community of Pilot Mound, Iowa. But the river supplies water not only to nearby small towns and farms, but also to Des Moines Water Works, which serves around half a million people in and near Des Moines.

In Bismarck, the capital of North Dakota, the $3.8 billion pipeline was rerouted–without the need for protests–because it risked the drinking water supply for around 67,000 people who live there. Federal rules for pipeline location are stricter for higher-population areas, while low-population areas don’t get the same protections.

“Bismarck qualified for the extra protections, Standing Rock did not, nor did the crossing at the Des Moines River,” says Carolyn Raffensperger, an attorney and executive director for the Iowa-based Science and Environmental Health Network. “The nearest town to the Des Moines River crossing, even though [the river] is the source of Des Moines’s drinking water, is Pilot Mound, Iowa, which is five blocks long.”

[Photo: Jim Watson/AFP/Getty Images]

Protestors in Iowa fought against the pipeline construction for months, as they have in North Dakota, with some of the same protestors going back and forth between locations. “The resistance in Iowa has been as ferocious, in some ways,” says Raffensperger, who was also the first attorney on the ground at Standing Rock. “Not as visible. We’ve had well over 400 arrestees. Between Standing Rock and Iowa, we’ve had over 1,000 arrestees.”

The 1,170-mile pipeline, which crosses four states, is designed to carry about half a million barrels of oil a day from the Bakken oil fields in North Dakota to Illinois. Sunoco Logistics, the company that plans to operate the pipeline, has had 274 hazardous leaks and spills in the past decade–more than any other company. In October, one of the company’s pipelines burst in Pennsylvania, spilling 55,000 gallons of gasoline into a river that supplies drinking water to 6 million people.

Landowners in Iowa are suing the Iowa Utilities Board for granting the permit, in part because they argue that the Board didn’t have the authority to take the land through eminent domain. One of the other issues at stake: The Utilities Board required the parent companies behind the pipeline prove that they have the funds to clean up a spill, and Sunoco Logistics hasn’t provided that proof. The lawsuit goes to court on December 15.