Houston officials continue to urge people to shelter in place and stay off flooded roadways as Harvey continues to batter the nation's fourth-largest city.
Public Information Officer Keith Smith also says rescue efforts continue and now are focused on those who feel trapped inside a home or building.
Smith adds the city's 911 emergency response system has been challenged by sharply increased call volumes since the tropical storm made landfall late Friday as a Category 4 hurricane.
He says during a typical 24-hour period, the emergency response system receives about 8,000 calls.
But during a 17-hour period following Harvey's landfall, more than 56,000 911 calls were received.
Meantime, Harvey continues to head back toward the Gulf of Mexico at a slow pace.
The National Hurricane Center says in its 4 a.m. CDT update that the tropical storm has lingered dropping heavy rain in the Houston area still has sustained winds of up to 40 mph (65 kmh) and is centred 20 miles east of Victoria, Texas, about 120 miles (193 km) southwest of Houston.
It continues to creep to the southeast at 3 mph (6 kmh).
That means it remains virtually stalled near the coast and continues to drop heavy rain on the Houston and Galveston areas.