Other cities have been through this battle with a storm’s leavings. After floodwaters inundated East Baton Rouge Parish, La., last year, crews collected about two million cubic yards of debris. Superstorm Sandy, in 2012, led to about six million cubic yards of debris in New York State — the equivalent of four Empire State Buildings, according to the Federal Emergency Management Agency. Katrina left behind 38 million cubic yards. Getting the stuff gone is a long process. It was only last month that Baton Rouge finished the debris removal process it organized in the wake of last year’s flooding there.

In Houston, where city officials say that some eight million cubic yards of debris will need to be hauled away, collection is farther along in some neighborhoods than in others. In Ms. Darby’s neighborhood, only a handful of volunteers were around to help in the disaster zone. In Bellaire, a wealthy city southwest of downtown, dozens of trucks were parked on the streets, their owners helping people bring their belongings outside. Poachers picked through the refuse for items that could potentially be sold, leading residents to spray-paint warning signs telling people to stay away from their debris.

The job of deciding how to move these mountains has been left to county and local officials, who hire debris removal companies to help them dig out. FEMA will reimburse the local governments for 90 percent of the cost.

One major removal company, AshBritt, already has “dozens of operations” going on in Texas from Harvey, said Jared Moskowitz, the general counsel for the company. He said he expects more to come.

Judith Enck, a former regional administrator for the Environmental Protection Agency whose territory included New York and New Jersey, said that environmental considerations have to be part of the process, even after a disaster.

Ms. Enck, who calls herself a “solid waste geek,” was heavily involved in debris removal after Sandy hit the Northeast. Figuring out what to do with debris is one of the most challenging aspects of any storm, and because decisions are generally made at the local level, she said, “every community has to kind of reinvent the wheel.”

Setting aside appliances like refrigerators for recycling, chipping downed trees for mulch instead of burning them, prevents pollution and extends the life of landfills. Leaking landfills can pollute groundwater. “The victims of these storms are already in environmentally compromised situations,” she said, “and the way debris is handled should not make it worse.”

She said that separating waste by type is anything but fussy, especially in the age of climate change, when scientists have shown that global warming is producing wetter storms and contributing to more destructive storm surges, and could also be making some storms more powerful.

“I fully understand people saying, ‘This is an emergency — let’s suspend the norms,’ ” Ms. Enck said. “But these hurricanes and floods are becoming the norm.”

Historically, Texas has not shown deep concern over environmental issues, and in the current crisis, its stance on debris removal has been similar. Governor Greg Abbott has temporarily suspended 19 environmental rules that the state said would “prevent, hinder or delay” Harvey disaster response.

After reviewing the changes, Andrew Dobbs, a program director with the Texas Campaign of the Environment, a nonprofit advocacy group, said, “They have suspended more or less every meaningful environmental protection.”

The communities hit by the storm “were already some of the most polluted in our country,” Mr. Dobbs said, “and the regulations in place were already insufficient to protect their health and well-being.” Relaxing the rules now, he said, will “escalate this problem in a dramatic way.”

At Ms. Darby’s house, the process of tossing and salvaging continued. With the help of some family members and their friends, the Darbys were packing some items into plastic containers for safekeeping at self-storage facility while they stay at a hotel. Flooding is not new to them: Tropical Storm Allison caused substantial damage in 2001, and the Darbys lived in a FEMA trailer while they fixed the house up that time.

As Ms. Darby decided what to toss and what to try to save, she reflected on how she had told herself a while back that she really should get rid of some things. “The Lord has a way of making you clean up and clean out,” she said with a laugh.

Her mother, Mary Darby, 84, was less sanguine, even after telling herself that the family had lost only possessions, not loved ones. Standing in her home, mold already visible on the walls, she began to cry.

“It’s material,” she said a few moments later. “But it hurts.”