Is it possible for a 16 inch concrete wall, reinforced with # 7 Bars, 9 inches on center, each way, each face to be watertight under normal conditions? Above walls are for a sewage pumping station, located where the water table is approximately 3-4 feet below grade and building extends 22 feet below grade. Pumping station is located in a wet area.
The concrete itself will be watertight if a 4000 psi mix (or better) is properly placed, compacted and cured. However, the thickness of the wall and the reinforcement must satisfy the structural requirements for the wall exposed to the water pressure. If this is not the case, cracks will occur, permitting leakage. Best insurance against leakage through structural cracks is the application of membrane waterproofing on the water side of the wall.