check for water source best if stopped at entry. Most brick veneer has a 3/4" space or gap from the wall, some masons put in weep holes (usually bottom course of brick) May want to check and see if plugged or put a few in yourself use a masonary drill bit. Also check for flashing at top of brick wall to stop water from entering. Is water problem seasonal for instance could it be caused from ice dams where water is back up under your roofing shingles and draining into the cavity between the brick and the wall. Good luck.