Gov. Greg Abbott is seeking federal aid for the Texas counties hardest hit by the latest run of storms that flooded thousands of homes and streets with reckless force.

In a letter dated Thursday, Abbott asked President Barack Obama to declare a major federal disaster in 12 counties, including Brazoria, Fort Bend and Montgomery, where the powerful storms and flooding swamped cars, ruined houses and businesses, washed out roads and ripped apart trees.

The governor's action is a necessary first step before Obama decides whether to release funds to the counties as they clean up from the storms. U.S. Rep. Kevin Brady tweeted that the state's congressional delegation had written Obama in support of Abbott's request. Officials said they expect a decision within days.

The president already had declared disasters in many of the same places after major flooding in April - an unfortunate fact that Abbott highlighted in his letter requesting more federal help. Major storms and flooding have hammered the Houston area on the last two Memorial Day weekends.

"The last year has taken a terrible toll on the people and the property of this state," he wrote Thursday. "Texans are resilient, but few can recover without assistance when disaster after disaster hits in the middle of recovery."

With a presidential declaration, people whose homes were damaged or destroyed can apply for a grant of up to $33,000 from the Federal Emergency Management Agency. The amount will depend on the severity of the reported damage.

In addition to repair costs, some aid can be used for certain medical expenses, funeral costs and damage to clothing or household items, among other losses.

Although Abbott has declared a disaster in 46 counties since June 1, his request for federal aid only covers those with storm-related damage "of such severity and magnitude that effective response is beyond the capabilities of the state and affected local governments."

Abbott wrote that the most recent storms, which began May 26, dumped up to 20 inches of rain in parts of Southeast Texas that typically receive 40 to 50 inches of rain a year.

Brenham alone had 16 inches on the first day of the storms, shattering the Washington County city's one-day rainfall record by more than 6 inches.

To make matters worse, the region had been pounded with heavy rain for weeks, so the ground already was saturated, the rivers, bayous and creeks already brimming. This latest rain had nowhere to settle.

By the time the Brazos River crested June 4 near Rosharon, it was nearly 10 feet above flood stage, the Nation Weather Service said. Officials expected the river to remain out of its banks through at least Wednesday as the high water makes its way to the Gulf of Mexico.

Cypress Creek and the Colorado, San Jacinto and Trinity rivers also reached major flood stages.

First the rain. Then the floods. Why is this happening? Find out with our new series Swamped https://t.co/ze5ZcLzSRH pic.twitter.com/NJrSBjdaQG — Houston Chronicle (@HoustonChron) June 3, 2016

In all, Abbott said the flooding threatened nearly 90,000 homes and forced mandatory evacuations in nine counties, including Brazoria, Fort Bend and Harris.

The severe storms were blamed for at least 20 deaths, including nine soldiers who were killed when their truck was overturned by swift water near Fort Hood, north of Austin.

A Montgomery County man, 77, was swept away while walking outside. In Washington County, the body of a 21-year-old Guardsman was found downstream from where his overturned truck had been located earlier.

Floodwaters remained a risk in some areas. While floodwaters slowly continued to recede Friday in northern Brazoria County, prompting the lifting of some evacuation orders near Rosharon, they were expected to remain high in the southern part of the county for several days.

"The water is pretty much holding. I don't think it's rising at this time," said Sharon Trower, county emergency management spokeswoman. "There are areas that are going to have water for several days, weeks possibly."

Brazoria County officials were offering free water testing to those with wells that may have been contaminated by floodwaters.

Fort Bend County was faring better, with a majority of residents having returned to life as usual since the floodwaters receded earlier in the week. But about 25,000 to 30,000 residents continued to face the aftermath of "real disaster," he said.

County Judge Robert Hebert said the county was "very pleased" by the governor's request. "It's very important," he said.

More than 1,200 homes had been reported damaged. Overall impacts in the county totaled more than $14 million, Hebert said, "and that number will only grow."

The county hoped to begin debris pick-up and home appraisals Monday for residents with affected property, many of whom remained focused on cleaning out their houses, Hebert said. "Those folks are going to need all the help they can get," Hebert said.

Emily Foxhall and Harvey Rice contributed to this report.