Many homeowners get confused when they see standing water in their basement, especially after there hasn’t been a lot of rain. If you check your pipes, your washing machine, and other sources of water but there are no leaks, it’s possible that the water is coming in from the outside.
Your basement is partially underground, meaning that it’s surrounded by soil. As much as we would like it to be, that soil that surrounds your foundation isn’t dry, meaning that your basement has to constantly combat moisture.
Hydrostatic Pressure
Hydrostatic pressure refers to the accumulation of groundwater against your basement wall. Properties surrounded by expansive soils are the ones most likely to experience hydrostatic pressure since clay soils are excellent at retaining water. If the soil was sandy, the water would simply drain away.
The weight of the water causes your basement wall to bow inward. Eventually, when enough weight is up against the wall, cracks will begin to appear on the concrete as it weakens under the pressure of the water. These cracks make it easy for the water to simply seep through the wall and into your basement. A clear sign of hydrostatic pressure is bowing walls and water coming from where the wall and floor meet.
Rising Water Table
The water table is an invisible line that indicates where the zone of saturation begins. The zone of saturation is the area underground where the soil is perpetually saturated with groundwater. Water tables are as deep into the ground as you may think. Sometimes, basements will be built just above the water table.
If your basement floods only during the rainiest times of the year, it’s possible that groundwater is getting in due to the rising water table. As water drains down from the topsoil to the zone of saturation, it accumulates underground until there is enough to cover your basement. If there are any cracks in your foundation, the water will get through.