The incident happened shortly before 7pm on Wednesday at the filling station in Dungannon.
A NI Fire and Rescue Service spokesperson said that an 11-year-old male had fallen down a manhole in the vicinity of The Oaks shopping complex, with the 999 call coming in at 6.50pm.
Two crews were in attendance and used a ladder and breathing equipment to reach the youngster who was trapped in two foot of water at at the bottom. One firefighter used a 9-metre ladder and a harness.
The boy was conscious but had sustained minor injuries to his back. The Northern Ireland ambulance service confirmed he had been taken to the Craigavon area hospital for further checks.