It's virtually impossible to water proof concrete, the water pressure is such that it'll force its way through the smallest pinhole/crack. This could be fixed

It's virtually impossible to water proof concrete, the water pressure is such that it'll force its way through the smallest pinhole/crack. This could be fixed on the inside by stripping everything back and with tanking membrane draining down to a sump with a RAID 1 array of sump pumps.