Cause of Basement Leak

Typically, the first and foremost reason behind a basement leak is cracks or gaps on the wall. When any structure is built the soil is dug and backfilled after the construction of the basement. In most times the soils surrounding your basement aren't fully compacted after the backfilling. Consequently, during heavy rain, the water is absorbed more than usual as the lesser the soil density is the greater the water absorption. In the process the soil expands and starts to put pressure on the basement walls, leading to cracks.

Now, our ground is saturated with water to a certain extent, but after rain when soil absorbs water, it starts to be fully saturated. Eventually, the soil can no longer absorb water but due to the rain, the amount of water is still increasing. In such situations due to the pressure of the access water on it, the soil starts to absorb the water while pressuring the previously absorbed water to move. Hence, water is pushed to get into the basement through the cracks and gaps if existed.