I just purchased a moderate-size two story house in Pittsburgh, PA built in the 1940s. The home has a full basement - boundary in black in drawing. It was formerly rented, so there is no available history regarding water issues. The house sits on a lot that slopes away from the house on all sides, but there is still water in the basement - with free water pooling in the garage, damp floors on the right side and front; and warped exterior walls in the garage and front. The neighbors also have a damp basement, requiring a dehumidifier. All downspouts seem to be in working order and leading to black flex pipe that discharges >15 ft from the house. My house has an internal french drain and sump system along the back wall, under the area labeled concrete porch pad. However, the construction dust from the masonry cutting is still there and completely dry, indicating that there has never been water there. The front and rear walls bow (ie not vertical) to a net 2" midway down the wall. The window wells are currently uncovered and I plan to add covers. I have a quote for an interior french drain system that would encircle the basement. My concern here is that I would need to demolish the basement full bathroom in the front left corner. I also question that the interior french drain is necessary and whether a dehumidifier, combined with (1) improving the sealant btw the concrete pad and the house and (2) sloping the outside so that water drains away from the house with (3) the use of a waterproof barrier. I think that it is worth trying 1, 2 and 3 before spending big $. My questions: a. If is worthwhile, how wide does the sloped plastic need to be in order to move the water away from the footer? What type of plastic do I buy? What do I do with the plants that currently live within the boundary of the plastic? Do I need to fix the plastic to the wall, or just pack it against it and ensure that it has a steep pitch running away from it? b. Or is it necessary to rent a ditchwitch and install an exterior french drain? I do have sufficient slope to drain it away from the foundation. c. Any opinions on carbon straps to right the walls that are bowing? d. Any recommendations for a dehumidifier? I plan to buy a 40 or 50 pint with a drain pump to pump the water into a floor drain. All help is greatly appreciated.