Brazilian authorities will declare a public disaster in the flood-sticken northeastern city of Natal on Monday ahead of the US-Ghana World Cup game.
A municipal spokesman said the deluge would not affect the stadium or access to the game, the second match to be held after Mexico's rain-soaked victory over Cameroon on Friday.
Declaring an emergency is necessary to cut through red tape and get aid faster, the spokesman said.
US Vice President Joe Biden will attend Monday's Group G game.
The city has endured three days of non-stop rain that has caused floods and landslides, destroying 20 homes and damaging 65 others.
FIFA was forced to cancel its Fan Fest on Friday in a place normally known as "Sun City."