Locating where water is entering your home is key to solving the wet basement problem, so mark the source whenever the seepage is active. Basement leaks are frustrating and can cause damage to your property.
Through the walls:
The most common basement leak is due to seepage through wall cracks. These cracks will continue to deteriorate and will eventually leak, and this seepage will get worse over time. Other possible wall leaks are tie rod ends, honeycombed concrete, and pipe penetrations.
Through the floor or floor/wall joint:
Most modern homes are built with a drain tile system around the footings to keep water from creating pressure against the floor or cove area (floor/wall joint). Some drain tiles run into the sump pump, others to the city storm sewer system. If seepage occurs in this area, check your pump's operation first; if that is working normally, then your drain tile is not.
Over the top of the wall:
Water entering at the top of the wall between the concrete and wooden sill-plate is a common basement leaking problem due to one of two things: The soil grade has been built up outside the home, higher than the concrete. Homeowners, in their efforts to keep water away from the foundation, build the dirt level higher than the concrete wall, ironically creating a seepage problem through the below grade brick or siding.
Sometimes there is an above-grade penetration of water, due to a caulking or tuckpointing issue. Any water that penetrates the veneer of the house will run down the backside of the siding and appear at the sill-plate juncture in the basement. The surest way to verify which of these two "spillover" problems you have is to water test by running a hose on the ground on a dry day. If water comes in, it is a below-grade problem. If water does not come in, then it is an above-grade problem that will require caulking, tuckpointing, or possibly roofing repairs.
Surface water runs down foundation walls:
Saturated soil then forces the groundwater to be pushed through porous concrete and cracks by hydrostatic pressure causing leaky basement issues. Leaking gutters cause basement water problems and storm sewers can also back up during heavy rains causing a leaky basement.
Clogged gutters are a prime source of surface water. Keeping gutters free of debris is important maintenance for homeowners to prevent the buildup of surface water. If the gutters are clean, perhaps there are not enough downspouts on the house's guttering system to handle a heavy rain.
Check during a heavy rainstorm and see if the gutters are overflowing. If they are, another downspout may ease the amount of water collecting around your foundation. Extending the downspouts away from the house by at least ten feet will minimize the surface water. Ten feet is the minimum distance required to discharge water coming off of your roof.
Paved areas that slope towards the house will funnel surface water towards your foundation. Sometimes paving settles over time due to aging or improper installation. It is important to make sure all paved areas slope away from the home.
The ground around the home should also slope away from the foundation. Ten feet is the recommended distance the water should be moved away from the foundation. If the ground has any depressions within those ten feet, they should be filled with dirt so the water drains away from the house. Using a clay rich soil in the depressions will repel water better than sand-based soil, which will absorb the moisture into the ground rather than repel it.
One other reason surface water can build up is irrigation systems that discharge too much water next to the house. The irrigation system should include a rain stat that turns the system off when the ground is saturated.