Any time there is some type of flood showcased in the news, while digging deeper into the event, you might notice the mention of the term ‘water table’ somewhere amidst the context of the story.
Perhaps you have heard this phrase in conversation with a friend, realtor, contractor, or the like referencing something having to do with a water table at someone’s home.
So, exactly what is a water table on a house?
The water table is a boundary located underground in between the area where groundwater saturates spacing between sediments and cracks and rocks & the soil surface above it.
At this boundary, water pressure and atmospheric pressure are equal.
Below the water table lays a saturated zone where water fills all spaces in between sediments and within the rock itself.
The height of this water table can be very different in areas and even within the same area…does that make sense?
In other words, it is not inconceivable that the water table levels within someone’s same property can vary, it all depends on the geology of the property.
The water table can also vary in levels at different points in the year.
As an example, in New England, during late Winter and Spring when snow melts and precipitation may be high, the water table will rise.
During Summer on the other hand, the water table goes down as days are a bit drier and plants take up water from the soil surface prior to it sinking down toward the water table.
When the water from melting snow or falling precipitation hits the soil, there is a bit of a lag from the time that water starts sinking into the soil (as the water has to trickle down and fill the spaces in between the sediments) and the water table rises.
The saturated zone below the water table is called an aquifer – basically a big storehouse of water.
This water is what is referred to as groundwater.
While melting snow and rain events are terrific avenues for replenishing groundwater, because of the time it takes for water to sink down through the soil and reach the aquifers, too much moisture, too quickly can oversaturate the soil and lead to the flooding that is often experienced with certain storm events.
If an area has a higher water table, the easier it will be to flood as the area below the ground will become overly saturated with water at a quicker pace.
Homes with basements built in areas with higher water tables should strongly consider having some type of basement waterproofing solution in place (including but not limited to a proper sump pump system) in preparation for a time when they may be more prone to flooding.
There are companies that specialize in waterproofing basements and the more reputable ones should definitely be leaned on for guidance as to how to best protect your basement.
The knowledge of water table location is also useful in construction as one is building a home, particularly when it comes to homes that will draw their water from a well or deciding on a location to build that may be less susceptible to flooding.
While not something the average person may need to think about every day, the knowledge of what a water table is and how it may affect things such as flooding might be useful to be aware of, particularly if you live in an area that has seen its share of flooding in the past.
