In much of the state there were small signs of a return to normalcy: Interstate 80 reopened near Iowa City in eastern Iowa for the first time in days, with Interstate 380 to the north scheduled to reopen early Tuesday. On the University of Iowa campus, officials began to take stock of the damage.
And in Des Moines, where a levee failure Saturday sent water pouring into the Birdland neighborhood, some residents returned for the first time to see the damage.
"It's really bad. I mean, I can't believe this," said Gloria Ruiz, whose home suffered flood damage.
Ruiz pointed to a dirty line about 5 feet up on her basement wall showing how high the water rose. Her washer, dryer and boiler, and most of her children's toys, including a stereo and an Xbox video game system, were ruined.
Floodwaters lingered about 50 feet from her driveway.
"We don't know how long it will stay like that," she said.
Where floodwaters remained, they were a noxious brew of sewage, farm chemicals and fuel. Bob Lanz used a 22-foot aluminum flatboat to navigate through downtown Oakville, where the water reeked of pig feces and diesel fuel.
"You can hardly stand it," Lanz said as he surveyed what remained of his family's hog farm. "It's strong."
LeRoy Lippert, chairman of emergency management and homeland security in nearby Des Moines County, warned people to avoid the floodwaters: "If you drink this water and live, tell me about it. You have no idea. It is very, very wise to stay out of it. It's as dangerous as anything."
Gov. Chet Culver and others pointed to the next looming trouble spot, in southeastern Iowa. Most requests for state aid were coming from Des Moines County, where the Mississippi River was not expected to crest until Wednesday. The county spent Monday sandbagging weak points on a major levee that, if broken, would cause flooding in several thousand acres and about 250 homes, said Gina Hardin, the county's emergency management coordinator.
"We're holding it back for now," she said.
The federal government along the Mississippi River if the weather forecast is on the mark and a massive sandbagging effort fails to raise the level of the levees, according to a map obtained Monday by The Associated Press.
Brian Wiekand, 48, of Oakville, was sandbagging the levee Monday evening near a drainage pumping station, south of Kingston on the Mississippi River.
He was concerned about more flooding as water began lapping to within a foot of top of sandbag wall.
"The Bible says the prayer of one man, God hears," Wiekand said. "Here's my prayer: I ask for the strength of God to fight this flood, and I ask for the grace to accept whatever happens."
Two more deaths were reported Monday, bringing the state's death toll to five.
Also Monday, the American Red Cross said its disaster relief fund has been completely spent, and the agency is borrowing money to help flood victims throughout the Midwest.
In the college town of Iowa City, damage appeared limited. Some 400 homes took on water Sunday, and 16 University of Iowa buildings sustained some flood damage over the weekend. But the town's levees were holding and the Iowa River was falling.
Officials in Illinois were building up the approach to the only major bridge over the Mississippi River linking Hamilton with Keokuk, Iowa, so the bridge could stay open despite rising water.
In Cedar Rapids, hazardous conditions forced officials on Monday to stop taking residents into homes where the water had receded. Broken gas lines, sink holes and structural problems with homes made conditions unsafe, said Dave Koch, a city spokesman. Officials hoped to allow residents in soon.
Frustrations spilled over at one checkpoint, where a man was arrested at gunpoint after he tried to drive past police in his pickup truck. All manner of refuse could be seen floating down the Iowa River - 55-gallon drums labeled "corrosive," propane tanks, wooden fences and railroad ties. Dead birds and fish sat on the city's 1st Avenue Bridge.
Officials plan to let more people into the flood-ravaged neighborhoods, but
on a case-by-case basis, CBS News Correspondent Cynthia Bowers reports.
A few blocks away, a paint store stood with its windows blown out. A line indicating the high-water mark could be seen about 8 feet above the floor. At the gas station next door, strong currents had knocked over two pumps.
Also mixed into the floodwaters are pesticides, herbicides and fertilizer from Iowa's vast stretches of farmland.
Ken Sharp, environmental health director for the Iowa Department of Public Health, acknowledged that the floodwaters had the potential to make people sick. But he said the sheer volume of water can dilute hazardous substances.
"We don't typically see mass cases of disease or illness coming from floodwater, but under any circumstance like this, we want people to avoid it because we don't know what's in there," he said.
The flooding also raised concerns of contamination in rural wells, said G. Richard Olds, professor and chairman of the Medical College of Wisconsin.
"For rural folks, it's going to be hard to know if their water's safe or not," he said.
In addition to the poison in the water, there are mosquitoes - millions of them spawning in acres of standing water. Greg Burg, assistant director of undergraduate biology at the University of Kansas, said the flooding "adds that much more water where they could potentially lay eggs and have the eggs survive."
Business was already heating up at Mosquito Control, a Rolfe, Iowa-based company that sprays insecticide from a crop-duster airplane.
"We are already getting several calls that mosquitoes that have finally hatched," co-owner Rich Welter said. "We're hearing from folks around Cedar Rapids and all around the northern half of Iowa."
When the waters rose Sunday in Oakville, a town of 400, Lanz and his family tried to move their pigs out of harm's way. But they could only save a few. Most of their 350 sows and their 800 piglets were lost.
The family ripped out canvas ventilation curtains in the barn so the pigs "could at least have a chance," said Logan Lanz, Bob Lanz' grandson. "They were screaming. They were on top of each other. We had some big sows in there. They're frantic, and they run you over."
He said the water was choked with dead piglets.
Near Iowa City, Angela Betts and her three children were among those who fled last week when the Iowa River burst through a levee at Coralville. She stayed just long enough to fill two trash bags with clothes.
The family is now living in a shelter, and as far as Betts is concerned, everything she left behind can stay there.
"It bothers me, with everything that's in the water," she said. "I probably won't keep anything. It won't be worth it."