"Having weathered plenty of hurricanes in the Out Islands of the Bahamas where my family lives and living in Charleston for 10 years, I have never seen rainfall like this".
The county government said 100 people had been rescued from vehicles after trying to cross flooded roads while state officials reported a total of 200 swift-water rescues around the state.
Live 5 News Meteorologist Bill Walsh says the rainfall potential for Saturday is between 8 to 12 inches.
Of the 83 road closures throughout the state early Sunday, 46 were in Charleston, Rousey said.
South Carolina Governor Nikki Haley has warned of the possibility of record-setting rainfall over the weekend and President Barack Obama on Saturday issued an emergency declaration for the state, ordering federal aid for areas affected by flooding.
The situation is so extreme that the helpers are in need of help as well.
The Red Cross has opened 26 shelters across the state. Firefighters are responding to calls while residents are escaping their homes by boat.
Cities up and down the East Coast are flooded from heavy rain.
South Carolina authorities say a woman was killed when her vehicle was swept into flood waters in Columbia. The deaths were blamed on the weather. "Turn around, don't drown", it said.
The city towed 75 cars from the water during the storm.
The flash flood watch includes Charleston, Berkeley, Dorchester, Allendale, Beaufort, Colleton, Hampton and Jasper counties until Sunday at 2 p.m. If you are bilingual and would like to volunteer to help you can call the Red Cross to 843-757-7437.
The water was still feet away from Joe Shetrom's door overnight, but even that came as a surprise to him.
"We are used to flooding in the area, but this is extraordinary", said police sergeant Edwin Graceley. "I feel very fortunate that we were able to get through this as well as we have".
Lauren Tuorto closed her Holy City Consignment shop on the Charleston peninsula until Tuesday.
Along South Carolina's coast, officials in Georgetown were not letting people into the city Sunday because of flooding of several feet on a few roads in the waterfront historic district.
The National Weather Service warned of "potentially historic and life-threatening flooding" across the southeast of the United States. And it comes from two sources. City officials closed the area to incoming traffic Saturday because of flooding from heavy rains.
The hurricane center said Joaquin would begin weakening through Sunday, but would remain a hurricane in its northeastward trek.
Charleston Mayor Joseph P. Riley Jr. told The Associated Press that the torrential rain is over and that about an inch of rain or slightly more is forecast for the next 24 hours.
Meanwhile, high-tide floodwaters are receding along the lower Eastern Shore of the Chesapeake Bay. Wind gusts could reach 30 miles per hour and could topple trees.
"We're not out of the woods yet", North Carolina emergency management director Mike Sprayberry said late Saturday. And up to 4 inches could strike the waterfront between Georgia and New Jersey. "Also, runoff from previous rains are expected to cause further flooding near creeks, ponds and culverts that overflow".
Along with the Carolinas, New Jersey, and Virginia have declared states of emergency.