It could be months before the city of Cedar Rapids brings its flooded wastewater treatment plant back into operation. For now, the city is dumping 25 million gallons of raw sewage into the Cedar River a day.

Kevin Baskins with the Iowa Department of Natural Resources says his agency has been monitoring the water quality of the Cedar River, and several other rivers, since June 9. He says the results are not surprising. The rivers have extremely high bacteria levels.

"Some of our other samples have shown that we do have increased nutrient levels, including phosphorus and nitrogen," Baskins said. "We also have some higher levels of sediment, as you might expect, because of the erosion."

The D.N.R. has also been pulling out thousands of drums or chemical tanks that were washed into the rivers. But, Baskins says those dangerous chemicals have not polluted the waters as much as one might think.

"We have not seen high amounts of what we call volatiles or the industrial types of chemicals you might see – such as solvents," Baskins said. "There’s every chance that, as the waters recede, we may see more of that…but at least initially, as we saw the higher waters, (volatiles) were not something we saw a lot of."

While Iowans should avoid the Cedar River, or anywhere sewage water is being dumped, Baskins says the greatest health risk is in flooded basements. He says contaminants in a flooded river are quickly washed away, but the water that’s left behind carries greater concentrations of harmful bacteria. "So obviously that’s a concern," Baskins said.