More than 3,500 residents of Houston have been rescued since Tropical Storm Harvey began pounding southeastern Texas with more than 750 mm of rain and counting.
Tens of thousands displaced from their homes are being housed at evacuation centres which are now overcapacity forcing many to sleep in chairs or on the floor.
Officials began releasing water from two Houston reservoirs on Monday in order to prevent uncontrollable flooding in the downtown area.
Houston’s two main airports have been closed since their runways are completely underwater.
The Texas Gulf Coast is a key centre of the American oil and gas industry with some of the largest refineries in the United States halting operations.