The cause of a wet, leaking basement can be as varied as the damage it creates.

• High Water Table: Rain, melting snow or underground springs will contribute to the water table rising around a home. This can result in a build-up of water pressure beneath the floor and against foundation walls.
• Hydrostatic Pressure: The higher the level of water around a home, the greater the pressure on the water to seek entry into the basement through cracks and crevices in walls and floors. Initially, this water may enter and rest only in the block or in the pores of the concrete. That's where damp walls and damp floors come from.
• Capillary Attraction: Whenever water contacts a porous surface like a concrete floor or wall, it's natural for the moisture to be soaked up like a sponge. The continuous pressure exerted from the outside causes the floors and walls to store water like a reservoir, ready to burst.
• Settlement: As the ground around a home settles, the foundation can shift or crack.  The parging shield protecting the foundation can also crack and open, allowing water to flow into and beneath your walls and floor.
• Lateral Pressure: water penetration through your foundation walls. This can result from water movement through natural underground veins, from poor ground drainage or downspouts that empty too close to your foundation, or from water simply building up in the hole in which your house sits.
• Surface Water: Excess surface water penetrates the exterior foundation walls, and enters the basement through gaps, cracks, and seams. Excess surface water generally occurs as a result of non-functioning gutters and downspouts, or reverse grades. Both will send water toward the foundation instead of away from it.
• Footing Drains: The drainage system installed around the exterior perimeter of the foundation, down below the level of the basement floor, is designed to drain water that accumulates at the bottom of the foundation. If the drainage system fails, usually as a result of clogging over time, water builds around the exterior perimeter. Pressure is created when the water has no place to drain. It is only a matter of time before the water is forced into openings at the base of the foundation, usually through the seam where the wall and floor meet. If the foundation is built from hollow concrete blocks, water can rise upwards in the blocks, and show up in areas above the level of the floor.
• Vapor Transmission: Because foundation building materials are made from porous masonry products, water vapor can move through the foundation, from the cooler damper soils, into the warmer, drier, environment of the basement. This is the reason that vapor barriers are required when installing wall or floor covering.
• Humidity: In the warmer, humid months, warm, humid air circulating into the basement shrinks as it cools from the lower air temperatures in the basement. As the air cools and shrinks, the relative humidity increases. As it continues to cool, or comes in contact with cooler surfaces, like cold water pipes or cold concrete walls and floors, the water condenses. Cold water pipes drip water onto the floor. Dampness appears on basement walls and floors.