The National Weather Service is reporting that nearly all major rivers in the state are at or near flood stage.
In the Milwaukee area alone, more than seven inches of rain fell over the weekend.
Among the hardest hit areas in southeastern Wisconsin was Racine, where several people were forced to leave their homes.
The flood covered a half a mile radius in Racine. About 30 families had to be evacuated.
Close to 100 homes were being affected by the floodwaters, which began to rise Sunday afternoon and have now submerged the area immediately surrounding it. The fire department began evacuating people in the early morning hours Monday.
"The first evacuations were done just adjacent to the river, and at that time, water had filled the basements of those homes already," said Kevin Bush, Racine Fire Department. "The streets were completely out as they are behind me now, so we sent firefighters in on a boat and on a fire rig to take those people out of immediate danger."
"They made us leave. So we left for a couple hours. We have been back and forth since then just to make sure that the house is OK," said flood victim Edward Desotell.
Many houses have sustained only minor flooding because of the way the homes are raised above the street level. Still, there are just as many who have not been so fortunate.
"We have about eight inches of water in the basement, and I imagine it's water that has seeped in and it's also sewage. So we're pumping it out as fast as we can," said Rudy Peterson.
Just two blocks away, another home sits in what is likely Racine's lowest point across from a large park. The owner could be the flood's hardest hit victim.
" It's sad to have to think I'm gonna lose everything I just look out here and I see this water getting higher and higher," said Vicki Waschbisch.
Outside of Racine, people have been evacuated from their homes in at least nine counties across Wisconsin. Governor Jim Doyle has already declared a state of emergency. No deaths or injuries have been reported as a result of the floods, and officials hope the worst may be over.
"By seven o'clock tonight, the river should be at its high crest stage and then slowly start receding," said Gary Becker, mayor of Racine.
Even though it hasn't crested yet, the river reached over 11 1/2 feet. That is a record high for the area. Becker also said that when all is said and done, the city will provide sump pumps to help residents dry out their basements. They say they believe that at this point flooded basements is the most damage that most homes should have. They expect the damage to not exceed the 100 homes.
Elsewhere in Wisconsin, the heavy rain caused Lake Delton to overflow and empty Monday.
At least four houses tumbled into the water and started floating downstream with the heavy current. The lake is near the Wisconsin Dells.
Dell Creek Dam on Lake Delton did not fail, but when the water overflowed, it created a new channel that emptied the lake.
Water rushed over the nearby highway and then washed it out. Lake Delton is now just a pit of mud with boats resting on top of the now empty lake bed.
Sauk County emergency management director Jeff Jelinek said he was not sure whether there were any injuries, but said people had been told to evacuate the area, which is about 50 miles north of Madison.
A couple thousand people in Columbia County, about 30 miles north of Madison, were urged to evacuate below the Wyocena and Pardeeville dams, said Pat Beghin, a spokesman for the county's emergency management.
The Wyocena Dam's spillway had washed out, and workers were sandbagging to try to save the dam, Beghin said. The Pardeeville dam was overflowing, creating a risk for the nearly 10,000 people downstream in Portage, he said.
The Upper Spring Dam in Palmyra was failing, state emergency management officials said. But only one house in the rural area was in danger, Palmyra town chairman Stewart Calkins said.
Wisconsin Department of Natural Resources engineers were being sent across the state to survey other dams.
Gov. Doyle had declared states of emergency for 30 counties. At least 130 inmates from the Department of Corrections were helping sandbag in nine areas, according to the state emergency management. The Red Cross had 11 shelters open across the state and was preparing a 12th, officials said.
A new storm system was headed toward the Ohio Valley from the southern Plains on Monday -- Oklahoma got up to 6 inches of rain by late morning and utilities reported nearly 5,000 customers blacked out -- and the National Weather Service said as much as 3 inches of rain could fall on already waterlogged Indiana late Monday.
The Associated Press contributed to this report.