Have you ever wondered where the water you drink comes from? It all starts right beneath your feet. Well, maybe it doesn’t all start out as ground water, but science estimates there to be approximately 2.78 million trillion gallons of ground water on—or technically in—our planet. That makes up about 30.1 per cent of the world’s fresh water. In the US, 349 billion gallons of fresh water are withdrawn every day, and of that, ground water is estimated to provide 79.6 billion gallons—that’s 26 percent of the water the entire US drinks, cooks with, and showers in.
In other words, a lot of our water comes from the ground, but technically, unless it’s falling on us, most of the Earth’s water is on the ground—so what exactly is ground water?
Ground water isn’t just the water you get off of the ground—or under the ground, for that matter; it actually describes the water that exists in the ground. Ground water is the water that exists in the openings and cracks between beds of rocks and sand within the ground. Think of it like when you are at the beach. When you dig a deep enough hole, it usually starts to fill up with water. Well it isn’t actually filling with water just because you dug the hole; that water was there to begin with. What you’ve done is dug down as far as the water table (which is much closer to the surface at the beach because of your proximity to that giant body of water beside you).
What is a water table?
Every drop of water that hits the surface of the ground works its way down through rocks, sand, gravel, etc. to the ground water in the water table. This doesn’t mean that there is a giant underground stream beneath your feet, although in some cases there are underground streams, lakes, or veins; it just means that the water pools at the level of the water table in-between all the particles of dirt and rock that exist in the ground—just like a sponge holds water. This is the water you want to access when you dig a well.
The region below the water table is completely saturated with ground water, and that water, while it is still added to by the surface water that gets absorbed into the ground, flows laterally. This is why pollutants pose such a problem. Pollutants don’t just stay where they are spilt. Once they reach the ground, they run the risk of seeping through the ground and into the water table, where it can then flow to wells, lakes, and streams, even reaching several miles away from where they entered the ground.
Can’t the ground filter out the pollutants?
Soil, in fact, does act as a filter. That’s how septic systems work. But soil and ground can’t filter every toxin. Some chemicals, like benzene, toluene, ethyl benzene, and xylene (BTEX)—the chemicals which are added to gasoline in order to increase octane—cannot be filtered by the ground, though, which means they often reach ground water and can contaminate wells, rivers, streams, etc.
Don’t forget that our water system is connected. This means the water that washes off our roads and highways is connected to the water in our rivers, lakes, streams, oceans, ponds, wetlands and wells. If we want to protect the ground water we drink, then we need to be conscientious about where our water comes from and how far it has to travel to get to us.
Accessing ground water
Anyone in rural areas without a municipal water supply is familiar with the need to have a well. Well drilling is expensive and the bad news is, you pay for the drilling whether or not water is found. Thankfully, we no longer rely on outdated modes of water finding, such as dowsing, and rely on scientific methods that accurately find ground water so the drillers know exactly where to drill. This act of finding water saves money, stress and labor in the long run – you do not get several dry wells on your property before the driller hits water.
American Water Surveyors is a premier service provider in the water finding industry. If you want to know the location of your ground water – along with depth and yield – before you dig your well, call American Water Surveyors today.
