What is Groundwater?

It shouldn’t come as a surprise that groundwater is an essential natural resource in abundance. When it comes to global fresh water, over 9% of it is, in fact, groundwater. In comparison, surface water that includes rivers and lakes just consists of 3% of the freshwater.

Like most countries, half of the American population depends on using groundwater as the primary source of drinking water. Historically, groundwater has always been vital for water irrigation purposes. On the flip side, groundwater is vulnerable to a wide range of pollutants.

The focus of this article is to help you understand the basics of groundwater, its mechanics, use cases, and potential sources of pollutants that impact groundwater.

What Exactly Is Groundwater?

As the title suggests, groundwater refers to the water that gets soaked from the rain soil or other type of precipitation. Groundwater moves in the downward direction and fills out the bed cracks and openings of sand and rocks.

Despite different environmental conditions and renewal rates, groundwater fundamentally is, in fact, a renewable resource. Aquifer refers to the groundwater that is stored and then moves through the specific geological formation of sand, rocks, or soil.

The saturation zone comes into the fold when the water fills a specific area of the aquifer. In a traditional sense, you can locate this water table just a foot below the surface ground. On the other hand, the water table is often located hundreds of feet below the surface area.

What are Aquifers?

Aquifers are composed of sandstone, fractured rock, or gravel. Whether it’s small or large interconnected space, water has to move through these types of materials.

Mechanics of Groundwater

In terms of speed, the flow of groundwater comes down to the space size in the rock or soil. Also, the interconnectedness of the soil can speed up or slow down the flow of groundwater. On a global scale, you can find groundwater pretty much everywhere.

But depending on the external factors, the water table can be shallow or deep. In most cases, the melting of snow or heavy rains propel the rise of the water table. Manually, you can raise the water table by pumping groundwater supplies.

Like surface water, groundwater is attached through a continuous water circulation or hydrologic cycle in the earth’s atmosphere. Most of the groundwater stems from precipitation that can infiltrate the soil zone. Once the soil zone is saturated, groundwater starts to percolate in the downward direction.

Unlike surface water, groundwater is always in motion. But the flow of groundwater depends on the aquifer’s storage capacity and transmissivity rate. The outflow of natural groundwater occurs through riverbeds and springs when there is a high ground pressure than the atmosphere. But it takes a lot of effort to determine the internal circulation of the groundwater. But if the water table is near, then the average water cycle time can be less than a year.

What Makes Groundwater So Important?

Although a huge quantity of groundwater gets distribution across the world, most groundwater reservoirs are not investigated or underdeveloped. According to scientists, there are around 5.97 quintillion gallons of groundwater within 2 km of Earth’s upper surface.

Groundwater: Key Stats You Should be Aware Of

  • According to the U.S. Geological Survey, groundwater represents 37% of water source distributed for public use in the United States.
  • WHO states that 1 out of 10 people don’t have access to clean drinking water. In African countries, most people have mobile phone access rather than clean piped water.
  • UNESCO highlights that groundwater distributes ½ of all safe drinking water across the world.
  • Groundwater distribution represents 43% for irritation use throughout the world.
  • Over 65% of groundwater is mainly utilized for irrigation that involves food production
  • Asia represents 2/3rd of the abstracted groundwater in the world.

Modern Use of Groundwater

Modern-day use cases of groundwater largely boil down to industrial processes, agricultural irrigation, and residential and municipal water supplies. You may not be aware of it but major American cities like Memphis, Tucson, Miami Beach, and Honolulu get their water supply from aquifers. What’s interesting is that 98% of rural households get their water supply from private wells.

In 2022, ranchers and farmers in Western states continue to significantly use groundwater to irrigate their crops. Down to the southern and eastern sides, agricultural and drinking water stems from streams and lakes. But most industries need a huge amount of groundwater for refining petroleum, manufacturing steel, mining, and producing plastics. In the agriculture sector, states like Louisiana, Alabama, and Mississippi need groundwater to support fish farming.

Groundwater Sources of Pollution

Septic Systems

Offices and homes use wastewater disposal solutions and these systems are not connected to the main sewer system of a city. Septic systems ultimately drain the human waste below the ground at a slow speed. But improper construction, maintenance, or design of the septic system leads to leakage of viruses, bacteria, and household chemicals into the groundwater.

Storage Tanks

In the United States alone, there are more than 10 million buried storage tanks. And buried storage tanks are bound to crack, corrode or develop leaks. Once these contaminants leak and mix with groundwater, it can lead to serious contamination.


When it comes to groundwater, one of the major sources of pollutants is landfills. These sites are used to dump or bury garbage. But landfills usually need a protective ground layer to avoid potential contaminants mixing into the groundwater. Without this protective layer, landfill contaminants in the form of paint, battery acid, or household cleaner seep into the groundwater.

Atmospheric Pollutants

Recently, atmospheric pollutants are on the rise in the context of groundwater. When it comes to the hydrologic cycle, oftentimes contaminants from other cycles like surface water or atmosphere become part of the groundwater supplies.

Hazardous Waste

In the U.S., there are many hazardous waste sites that contaminate groundwater. In most cases, contamination occurs when there are many barrels or containers with hazardous materials just lying around onsite. In case of a leak, contaminants find their way to the soil and mix into the groundwater.

Final Thoughts

Whether it’s arid or semi-arid zones, development requires groundwater. Today, groundwater has become integral to support huge industrial and agricultural operations. Without groundwater, large and small enterprises would not be able to conduct vast operations and cease to exist.