World Water Day 2022 – March 22, 2022

(by Advisory Committee Member Eric Strom)

What is World Water Day 2022? An event sponsored by the United Nations and over 24 international organizations concerned with fresh water supplies and protection worldwide. It occurs on March 22 each year, and this year’s theme is Groundwater, making the invisible, visible. Following is a collection of some interesting facts gleaned from articles, studies, and websites done by the organizations and government agencies listed at the end of this writing.

Ogalalla Aquifer

Groundwater – what is groundwater? It is water that is in the ground beneath us. The top of the saturated groundwater is called the ‘water table’. Groundwater occupies the spaces in gravel, split rock, sand, and other subsurface materials. Aquifers are saturated areas of groundwater, and may be well defined. The Ogallala Aquifer is the largest aquifer in the United States. It is part of the High Plains aquifer system, which underlies parts of eight states from Texas to South Dakota. An aquifer may be a few feet to several thousand feet thick, and less than a square mile or hundreds of thousands of square miles in area. For example, the Ogallala Aquifer underlies about 280,000 square miles in 8 states— Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming.

Almost 90% of the freshwater on earth is groundwater, and 60% of the US uses it for drinking water. It is also the largest source of US crop irrigation water at about 43% and accounts for about 1/3rd of industrial water used. Groundwater in the US is 96% freshwater, and about 4% brackish or saltwater.

There is an immense amount of water in aquifers below the earth’s surface. In fact, in the contiguous USA, there is over a thousand times more water in the ground than is in all the country’s rivers and lakes combined. 

Puget Sound Lowland

We live in what is known as the Puget Sound Lowland – bordered roughly on the north by the Fraser River and the US-Canadian border, on the west by the Olympic Mountains, on the east by the Cascades, and on the south by the Chehalis hills. The Lowland covers about 17,600 square miles, about 2,500 square miles of which is saltwater. There are at least 30,000 freshwater wells in the Lowland most of which (80% or so) are less than 175 feet deep. Due the effects of glaciation, there is a large number of aquifers in the region. For a thorough discussion of the area, please see the USGS Professional Paper 1424-D in the Reference Section

In King County, Washington, 30% of the population uses groundwater as their primary source of household freshwater, either through local Water Districts, or individual wells. That amounts to approximately half a million people as of 2017. About 60% of Washington State as a whole uses groundwater as the primary freshwater source.

Many Water Districts in Washington have tapped aquifers for all or part of the fresh water they provide their customers.

Some groundwater is used and then released to surface water bodies, such as rivers or lakes, but it is almost never pumped back into the ground. Instead, groundwater is replenished almost entirely by rainfall. In the United States, roughly one quarter of all rainfall becomes groundwater.3 Water consumption refers to the water that is withdrawn for human use but not returned. Irrigation accounts for around 80% of fresh water consumption:7 most is lost to evaporation and the incorporation of water into crops. However, more modern irrigation methods, such as drip and buried drip systems do better at targeting specific areas and use much less water as a result.

10  Possible Sources of Groundwater Contamination

  1. Natural Sources – Some substances found naturally in rocks and soils, such as arsenic, iron, chlorides, sulfates, fluoride, or radionuclides, can become dissolved in groundwater.
  2. Pesticide and Fertilizer Use – Agriculture is a huge source of groundwater pollution. The spreading of slurry, fertilizers, pesticides, fungicides, insecticides, herbicides, and animal waste on the land can result in pollutants, such as nitrates and bacteria, seeping into underground water sources.
  3. Waste from Sewers and Other Pipelines – Sewer pipes carrying wastes sometimes leak fluids into the surrounding soil and groundwater. Sewage consists of organic matter, heavy metals, inorganic salts, bacteria, viruses, and nitrogen.
  4. Improper Disposal of Hazardous Waste – When we improperly dispose of materials such as cooking and motor oils, lawn and garden chemicals, paints and paint thinners, medicines, disinfectants, etc., they usually end up in groundwater wells.
  5. Natural Gas Drilling – Hydraulic fracturing, or “fracking” is a process used to drill for natural gas. A mixture of chemicals is combined with water and forced deep into cracks in the ground, opening them to gain more access to the gas. Some of these chemicals can then pollute nearby groundwater.
  6. Mining and Quarrying – Mining and quarrying can release pollutants previously trapped in rocks into surrounding underground water sources.
  7. Saltwater Contamination – When aquifers near the coast are over-pumped, there’s a risk of creating a vacuum that can quickly be filled with salty seawater.
  8. Landfills – Landfills are areas where our garbage is taken to be buried. They are supposed to have a protective bottom layer to prevent contaminants from leaching into groundwater. However, if there’s no layer or the layer is cracked, contaminants from the landfill (paint, acid, car batteries, household cleaners, etc.) can make their way down into groundwater. These contaminants can pose serious health risks to humans and animals.
  9. Military Bases – Military sites are home to some of the most dangerous contaminants, including trichloroethylene (TCE) and per- and poly-fluoroalkyl substances (PFAS). Even today, some US military facilities are plagued by contamination. Worse, some contaminants found in and around those facilities have drifted into some groundwater supplies.
  10.  Atmospheric Contamination – Ever heard the saying, “What goes up must come down?” Well, that principle also applies to pollutants released into the atmosphere. These contaminants eventually return to Earth in rain, snow, and other forms of precipitation. Surface water then leaches these pollutants into groundwater. Moreover, nitrates and sulfates emitted from power plants and factories can cause acid rain, which streams through the soil and acidifies groundwater supplies.

The Effects of Contaminated Groundwater

Contaminated groundwater can result in many unfortunate situations, including:

  • poor drinking water quality
  • loss of water supply
  • degraded surface water systems
  • high cleanup costs
  • high costs for alternative water supplies
  • potential health problems


  • Protection for public drinking water aquifers — Critical Aquifer Recharge Areas which have specific requirements and must be registered with the DOH.
  • Consistent testing of private well sources.
  • Pollution control and reversal where possible – groundwater pollution cleanup is generally prohibitively expensive, so pollution prevention is critically important.
  • Super-fund cleanup site expansion.
  • Education and activities to keep groundwater facts and exposure visible, such as World Water Day 2022.

Estimated Use of Water in the United States in 2010U.S. Geological Survey
Irrigated Agriculture in the United StatesU.S. Department of Agriculture
Groundwater FactsNational Ground Water Association
Ground-Water Availability in the United StatesU.S. Geological Survey
Groundwater Depletion in the United States (1900-2008)U.S. Geological Survey
High Plains Water-Level Monitoring StudyU.S. Geological Survey
Estimated Use of Water in the United States in 1995U.S. Geological Survey