President Barack Obama has signed a disaster declaration, ordering federal aid to help recovery efforts in South Carolina.
The president's action on Monday makes federal funding available to people in Charleston, Dorchester, Georgetown, Horry, Lexington, Orangeburg, Richland, and Williamsburg counties.
Assistance can include grants for temporary housing and home repairs, low-cost loans to cover uninsured property losses, and other programs to help individuals and business owners recover from the effects of the flooding.
The Federal Emergency Management Agency said damage surveys are continuing in other areas, and additional counties may be designated for assistance after the assessments are fully completed.
South Carolina Governor Nikki Haley made the following statement after the signing.
"Tonight's federal declaration was an extremely important first step in our recovery. We have now entered the largest recovery program our nation offers in an almost unprecedented timeframe. What this allows us to do is to assess the damage of this storm in every single county and continue to add to the list of those eligible for this support - a list we know will grow. The people of South Carolina have my commitment: at the end of this process every county and every person will have access to every resource we can get them. This will not be a short or easy recovery, but we will get through it, and get through it together."
The coroner for the county surrounding Columbia has released the names of several people found dead in flooded vehicles, bringing the death toll from the storms to at least 12.
Haley says South Carolina is facing rain and flooding the likes of which haven't been seen in 1,000 years, with 2 feet of rain reported in some areas. She told NBC's Today show on Monday morning, "Our obvious priority is safety."
Ten people have died in her state. Two have died in North Carolina.
The governor also says: 381 roads are closed, with 127 bridges down. More than two dozen shelters are open with 900 people. Over 1,000 law enforcement personnel and 1,000 transportation department workers are working. Utility crews are working to restore service to 30,000 customers. More than 40,000 people are without water.
Haley says most people are heeding her plea to stay off the roads.
"I think they get it. All you have to do is look out the window and see the flooding. It doesn't take long for you to get in your car and realize you've got to turn back around," she said.
A half-dozen fire trucks and pumps from cities in South Carolina have moved hundreds of thousands of gallons of water to a hospital in downtown Columbia.
Capt. Isaac Romey of the Columbia Fire Department said the crews from a variety of departments moved water from hydrants in a shuttle operation to Palmetto Health Baptist Hospital, which was without running water.
"The tankers pull the water out of the hydrants, move it into dump tanks and then pull it into the hospital," Romey said.
He said the operation began around 11 p.m. Sunday and was continuing Monday. The water is being used for uses other than drinking.
He said the operation had put at least 300,000 gallons into the system at that point, and he said it would go on as long as needed.
Officials at the University of South Carolina are bringing in bottled water and portable restrooms to help take care of the 31,000 students who attend the school's main campus in Columbia.
The city has warned all residents to boil water before using it for drinking or cooking. University officials say bottled water was delivered Monday to several on-campus buildings, and students in campus housing were being encouraged to use stoves and microwaves and common areas to boil water themselves.
Portable restrooms have been delivered to residence halls, sorority and fraternity houses and the student union building.
Officials say classes will also be canceled Tuesday. The campus is open, and officials say several dining areas and a counseling center are open for students' use.
Two members of the South Carolina Helicopter Aquatic Rescue Team based at McEntire Joint National Guard Base say they have rescued between 25 and 30 people over the last two days.
An online coverage map showed that power was out early Monday morning for more than 13,500 South Carolina Electric & Gas customers. Nearly 12,000 of those outages were in Richland and Lexington counties, where flood waters have been abundant in many neighborhoods and commercial areas.
Duke Energy said that about 7,800 of its customers had no electricity, primarily in the northwestern corner of South Carolina.
The National Weather Service says Sunday was the wettest day in the history of Columbia. The rainfall total at the Columbia Metropolitan Airport was 6.87 inches, the most rain that's ever fallen there in one day.
Forecasters say the old record of 5.79 inches was set July 9, 1959.
The two-day rainfall total for Saturday and Sunday was 10.44 inches. That breaks the old record of 7.69 inches set over August 16 and 17, 1949.
Since Friday, more than 20 inches of rain has fallen in some parts of Columbia. The Weather Service says Gills Creek, an area that has seen neighborhoods and thoroughfares under water, had recorded 20.28 inches as of early Monday morning.
Authorities have released information about a South Carolina Department of Transportation worker killed in the aftermath of torrential rains and historic flooding in the state.
The agency says in a news release that 45-year-old Timothy Wayne Gibson died in flood waters Sunday while overseeing work near downtown Columbia.
DOT says Gibson was working on Garners Ferry Road, a major thoroughfare into the capital city that has seen feet of water pooling in residential and commercial areas.
Transportation officials say Gibson was with the agency's Richland Maintenance Unit and was traveling in a truck that was caught in rushing waters, overturned and was swept away. An autopsy is scheduled Monday.
The storm stretched beyond South Carolina - in Georgia, more than 14,000 customers were still without power early Monday. That's down from 33,000 at the height of outages in the state. Many of the outages were in hard-hit Habersham County, where schools are closed Monday. Rain and high winds that toppled trees caused the outages.
The Associated Press contributed to this report