The death toll stands at nine, with a tenth person listed as missing.
CBS News Correspondent Mark Strassmann reports weather forecasters are monitoring a storm gathering off in the Gulf of Mexico southeast of Corpus Christi that could dump significant rain on parts of the state already overwhelmed by too much water.
The Federal Emergency Management Agency added the battered counties to the list of 13 other counties already declared federal disaster areas by President Bush.
Six more counties that the governor has requested declared disaster areas are still under consideration for that designation, which is crucial for financial aid in cleanup and rebuilding.
In flood-ravaged New Braunfels, near Austin, residents returned to their homes to survey the devastation left by the Guadalupe River.
The job now is shoveling out the greenish-brown mud which covers everything touched by the floodwaters. The Red Cross says some 50,000 families have been affected by the flooding. That's double the number of cases reported after Tropical Storm Allison last year, according to the American Red Cross. In some places, rivers have crested as high as 28 feet above flood stage.
"Once all these floodwaters recede, we'll see the impact," said Texas Gov. Rick Perry said after touring a flood-marred home in downtown San Antonio. "It's going to be substantial. ... This is another major, major blow to the state of Texas."
"It's just an incredible amount of work. We'll all be out here for weeks," one worker said.
Meanwhile, waters from weekend flooding in West Texas continues to recede.
All Abilene streets are open, and cleanup continues for hundreds of residents whose houses flooded Saturday after storms brought 6 inches of rain in a few hours. Other towns in the region got up to a foot of rain.
Runoff from that area caused Lake Brownwood to overflow into Pecan Bayou, which flooded a 2-square-mile section of Brownwood's business district.
Lisa May, who owns Humphrey Pete's and Skillet's restaurants along the bayou, rejoiced Monday when she saw that water didn't reach the 2-foot-high sandbags her family frantically piled against the doors early Sunday morning.
The parking lots remain flooded, and local restaurants are losing several days of revenues. But May said she feels fortunate.
"If the water had gone up another foot, it would have come in," said May.
San Antonio and points north moved further into cleanup Monday, but extensive flooding continues in less populated counties along the coastal plain leading to the Gulf of Mexico. Flood warnings were in effect in 15 counties.
The lower Guadalupe River, which poured out of Canyon Lake and tore a destructive swath through New Braunfels and Seguin, remains flooded as far south as Victoria, but it has crested and is receding in most places.
The torrent of water out of Canyon Lake caused significant damage to the New Life Children's Residential Treatment Center, which serves girls with severe emotional and behavioral problems.
The damage has forced its closure for at least three months, the center said. Forty-eight girls and 40 staff members were evacuated last week.
In Goliad, the San Antonio River is at 46 feet, more than 20 feet above flood stage, according to the National Weather Service. The river is expected to crest at 51 feet Wednesday. Officials there say only a small number of homes are flooded.
Water levels in the Medina River, which ravaged more than 100 homes in Bandera and Castroville, are falling over most of its length. The Frio and Nueces rivers are also receding.
Mike Buchanan, a forecaster with the weather service in Corpus Christi, said there was a chance that the storm front in the western Gulf of Mexico could grow into a tropical depression.
If that happens, he said, it could throw rain as far north as the Hill Country.
"There may be some additional problems as far as flooding is concerned," he said. "I don't think it would be a major impact, but it could be a minor impact. It's something to watch."
Buchanan said it is more likely that the storm would drop its rain on the lower Rio Grande Valley, now in the midst of a prolonged drought.