The problem: Cypress Creek in northwest Houston keeps rising and still hasn't crested, officials say, and forecasters expect more rain Wednesday.
In the town of Klein, John Martin stuffed his suitcase and bolted for a friend's house.
"I got a week's worth of clothes and all my important papers," he said.
His new car was one of dozens partially submerged in the complex parking lot, which now looks like a dirty brown pool. Neighbors tore down a fence in the back of the complex to move their cars to higher ground.
Ahmed Sharma and his wife, Emily, couldn't leave their apartment without the help of an inflatable raft tugged by their neighbors.
"We all knew it was going to rain, but we didn't know it was going to be this bad," Emily Sharma said.
The catastrophic flooding has killed seven people, flooded 1,000 homes and caused more than $5 billion in damage.
The Houston-area community of Hockley got pummeled with 17 inches of rain in less than 24 hours. That's more rain than Salt Lake City gets in a year.
"I think the worst is over for a lot of these areas," CNN meteorologist Pedram Javaheri said Tuesday. "Unfortunately, there's still plenty of rainfall in the forecast."
While the flooding began to subside in some places Tuesday, the Houston area can expect another 1 to 3 inches over the next few days, Javaheri said.
State of disaster
Of the seven fatalities, four people died in Houston, two died elsewhere in Harris County, and one person died in Waller County, the Harris County Institute of Forensic Sciences and Houston police said.
Gov. Greg Abbott declared a state of disaster for nine counties in and around the Houston area.
Emergency crews made more than 1,200 high-water rescues as some residents swam out of their homes.
Houston Mayor Sylvester Turner said the city will offer shuttle service to evacuees staying in shelters so they can return home and pick up any belongings "that may be salvageable."
He said many residents are eager to see what happened to their homes.
"We want to ease people's anxiety as much as possible," the mayor said.
At the height of the flooding, about 123,000 homes had no power, said CenterPoint Energy, the utility company that serves most of the Houston area.
By midday Tuesday, crews had restored power to most of the homes.
And the city has started making schedules for debris collection, said Janice Evans, spokeswoman for the mayor's office.
But given Houston's flat topography, the floodwaters won't disappear anytime soon, CNN meteorologist Chad Myers said.
'Turn around, don't drown'
The flooding this week made for some dramatic rescues, including a man who was seconds away from being submerged.
Just before members of a news crew from KTRK
were about to go on air at the edge of a flooded road, they saw the man's black Toyota Prius drive into the water and quickly float away.
The man opened the door, and reporter Steve Campion yelled for him to get out of the car.
"You gotta get out!" he yelled. The man hesitated as Campion yelled, "Swim! Swim! Leave the car. Swim!"
The man finally swam toward Campion, and as the reporter helped him onto dry land, the car disappeared beneath the water.
Campion said later, "It certainly is a reminder to turn around, don't drown. We say that in Houston so often, but you really never know how deep the water is."
Billions of gallons of rain
An estimated 240 billion gallons of rain fell on the Houston area in the past few days, Harris County Judge Ed Emmett said.
He called it the most significant flood event since Tropical Storm Allison in 2001, which left 41 people dead. It caused more than $5 billion in property damage in Harris County alone, the county's Flood Control District said.