No injuries are being reported from the collapse, which happened around 7:30 p.m. Monday in the city's Bella Vista neighborhood.
Officials say the wall damaged four properties nearby and forced at least eight people to evacuate.
The American Red Cross of Southeastern Pa. says it's assisting people who have been displaced by the collapse, which happened between some homes and a lot that is under construction.
The heavy rains also led to minor flooding as rivers and creeks throughout the Philadelphia area rose. Heavy winds also uprooted trees and caused other damage in some areas.