Clean-up efforts on a large manure spill in Brown County are wrapping up Thursday night.

More than 100,000 gallons of manure were reported to have leaked from a Humboldt farm into a nearby creek sometime Monday.

Now, the DNR is warning neighbors to watch their water.

The damage is still being assessed.

"There's not really a protocol," says DNR assistant spill coordinator Rick Joslin, after returning to his office from the sight of the spill. "Every spill is different."

The DNR says a storage valve left open Monday by a James Kroll farm employee caused the 100,000 gallon spill.

The farm is located on Finger Road, between County Road P and South Michiels Road. Officials with the DNR say the farm is not a CAFO--or concentrated animal feeding operation--and doesn't operate under a DNR permit.

"[The manure] flowed across his property into an unnamed stream that kind of meandered behind his farm, and it ultimately ended up in school creek about 3-3.5 miles away," says Joslin. "The farmer was cooperative. He did have VAC trucks on scene when we showed up."

On Thursday, two miles downstream, clean up efforts entering a third straight day.

Officials with the DNR are declaring School Creek may not be safe for people or pets. The creek is also a tributary of the Kewaunee River.

"You build a soil dam, basically--or a berm--set up a pump there," says Joslin, "and we found a pit nearby--a manure pit--and that's where it was brought."

From neighbors, many of which farmers, as well, it's a mixed reaction to the news.

Neighbors declining to go on camera say they aren't noticing any changes to their drinking water just yet. But they add they're concerned by spills like these, which they say aren't uncommon.

The DNR is urging people to report any changes in their drinking water.

"Recognize that, if you see a change, odor, or color in your drinking water," says Joslin, "have someone call the DNR."

Surface water samples should uncover the extent of the spill's contamination in the coming days.