MARIETTA - Cobb Commission Chairman Sam Olens said as many as 2,000 of Austell's 5,000 residents, nearly half, may be homeless, and it might not be any better in Powder Springs. More than 600 homes and 75 businesses in Cobb have endured "extensive" flood damage, according to initial estimates from the county. The Chattahoochee River from Holcomb Bridge to Peachtree Creek remains closed because of raw sewage flowing into the waterway and nearby neighborhoods from two compromised wastewater treatment plants located on its banks.

Olens believes the recent torrential rains have caused the worst flooding since 1919.

Fortunately, the county did not receive further rains Tuesday or Wednesday. Unfortunately, there is a 40 percent chance of potentially problematic thunderstorms today and Friday, and a 50 percent chance for storms on Saturday, according to the National Weather Service.

"Things are starting to subside, but you could see some heavy local rainfall," meteorologist Jessica Fieux said.

County officials are waiting for President Barack Obama to sign a disaster declaration, which Olens hopes to happen today. According to the White House, the president assured Georgia officials that requests for federal aid will receive prompt attention.

County spokesman Robert Quigley said, "The county is moving forward on repairs to public infrastructure while keeping excellent records so that we can apply for federal reimbursement once a disaster is declared."

Homeowners and property owners are encouraged to report any damage to their home or business to the county's Emergency Management Agency at 770-499-4566 or by e-mailing ema@cobbcounty.org.

The first dollar estimate on the damage in Cobb is expected in several days. Officials have estimated $250 million in damages statewide.

In the southern part of the county, subdivisions in Mableton and roller coasters at Six Flags are emerging from the receding, yet lingering floodwaters.

Cobb EMA Director Lanita Lloyd has called Clarkdale Elementary School a "total loss." Firefighters on Wednesday at around 11:30 a.m. were unable to reach a nearby burning home on Mitchell Lane and Clay Road due to remaining high water. Fire Lt. Dan Dupree said the home is completely destroyed, as is a Powder Springs home at 4051 Five Oaks Court following a Tuesday fire. A fire truck responding to that blaze became totally submerged in floodwater and was fished out Tuesday night. It is being evaluated to see if it is salvageable, Dupree said. The causes of the two fires are yet to be determined, while lighting has been blamed for six other house fires.

Olens said the Chattahoochee River and Sweetwater Creek are receding, though Sweetwater is going more slowly.

State Insurance Commissioner John Oxendine said the flooding of the two sewage plants due to the swollen Chattahoochee could add human waste and plant debris to the standing water in some nearby neighborhoods. Emergency officials warn all residents returning home of disease-causing bacteria and jagged debris harbored by stagnant, murky water.

"Clorox is going be your best friend," Oxendine said.

In the north, Allatoona Lake rose 15 feet since Sept. 15. On Wednesday, the lake level was 851.63 feet, which is more than 11 feet over the summer pool elevation of 840 feet. The U.S. Army Corps of Engineers is forecasting the lake to reach 857 feet by the end of this week, which would be four feet below the 1964 record high elevation of 861.19, said Ron Papaleoni, general manager of the Lake Allatoona Preservation Authority.

In an eight-day period that ended Tuesday, the National Weather service reported up to 20.37 inches of rain in parts of Kennesaw and nearly 19 inches in Marietta.

When Cobb does recover, one question will be whether officials allow rebuilding in flooded areas, Olens said.

Meantime, students in Cobb County schools and at Kennesaw State University returned to class today. Cobb Police have not yet reported any looting throughout the county. And the county's drinking water supply remains OK.

According to the county, "Cobb's water supply is safe to drink and does not require boiling prior to consumption. We have received some reports of slight water discoloration. Floodwaters have high levels of manganese and the Cobb Marietta Water Authority is working to address the issue. This water is fine to drink and the issue is being primarily reported in the east Cobb area. County crews have been able to restore water service to all but just a few customers and are working to accomplish this task."

Residents of Stephens and Douglas counties are not as fortunate. As of late Wednesday, many were without running water, emergency officials reported.

Roughly 40 roads were still closed throughout Cobb as of Wednesday night. Two hundred and thirty-nine people remained registered at the Cobb Civic Center's Red Cross shelter after being displaced from their homes. There have been no reported deaths in Cobb County due to the flooding. However, recent downpours and subsequent flooding have claimed the lives of at least 10 across the state and in Alabama.

Anyone wanting to volunteer and assist with recovery efforts should call Cobb's EMA at 770-499-4565. The Cobb County Legislative Delegation has also worked with the Center for Family Resources in Marietta to obtain donations that will go toward Cobb victims specifically. Information can be found at www.thecfr.org or 770-428-2601, extension 254.