You can probably seal the wall with any type of roll-on water-proofer; such as used on basement walls.

Pavement in parking area was sealed and painted in 2010.

Seal all accessible air penetration points between conditioned space and attic with low expansion foam.

My thought were to cover more of the sellers closing cost instead of adding to the price might seal the deal.

Look at sealing the building envelope.

buying in the Bayview sealed the deal for us.

you might need to peel back the carpet and use a shellac primer to seal the concrete.  

Both units need work; here are the larger items:Appliances (Unit A needs range + fridge; Unit B needs fridge): $1,500Floors (flooring needed in living area, hallway, bedrooms - probably use vinyl): $3,000Windows (need to be re-sealed) + New Doors (front screen door, doors in basement to yard, etc.): $1,500Paint (most rooms need paint): $1,000Roof Shingles: (may or may not need to do; roof missing a few shingles near gutter): $300Dryer Duct (missing a piece that connects from laundry room to outside, quick fix): $100Hot Water Heaters (electric) x 2: $2,000 (which is probably way high, but trying to be conservative).TOTAL ESTIMATED REHAB BUDGET (which is probably sky-high): $9,400ESTIMATED CLOSING COSTS: $5,000 all-inPROJECTED CASH-ON-CASH RETURNS: 14.91%=====================SECTION 8 PROGRAMI really need to educate myself on the Section 8 program. 

@Joe Kalis  I agree completely about the concern about water. if we remove the tub we will be able to see if the leak is caused by the plumbing or the poor seal around the current surround.If we use a liner and the water damage is caused by plumbing I will not have solved the problem so your point is a good one. thanks

Remember granite needs to be sealed and maintenance where as other countertops are lower maintenance.