The White House says it will ask the US Congress for emergency funding to help those affected by Hurricane Harvey.
President Donald Trump is expected to propose an initial $5.9bn (£4.56bn). Texas authorities say the state might need more than $125bn.
At least 39 people have died in the storm and its aftermath. East of Houston, floodwaters are still rising.
Visiting Texas, Vice-President Mike Pence promised federal help to “rebuild bigger and better than ever before”.
The BBC’s Barbara Plett Usher in Houston, Texas, says Congress is expected to act quickly on the request for initial funding when it reconvenes next week after its August recess.
But, she adds, that will be only the first tranche of money needed for the recovery.
Mr Pence said 311,000 people had registered for disaster assistance. It is not yet clear how quickly funds might reach victims.
Visiting the battered town of Rockport, Mr Pence paid tribute to the people of Texas: “The resilience of the people of Texas has been inspiring.”
He added: “The American people are with you. We are here today, we will be here tomorrow and we will be here every day until this city and this state and this region rebuild bigger and better than ever before.”
The White House also said Mr Trump would donate $1m of his own money to the relief effort. -BBC