What is Groundwater Pollution? (Definition, Real Cases and Solutions)


Groundwater pollution is a significant environmental issue since it could have a negative impact on ecosystems and human health. How does pollution of groundwater exactly happen? Why is it so crucial to comprehend how it happens? Many individuals are not aware of the possible sources of groundwater contamination or how contaminants might enter our water supply through the ground. In order to safeguard our ecosystem and provide clean drinking water, it is crucial to be informed on the realities surrounding groundwater pollution. We'll look at the causes, consequences, and mitigation strategies for groundwater pollution in this post. Continue reading to find out more about this crucial topic!


Groundwater pollution is a major environmental issue that affects the health of humans, animals, and ecosystems.

  • It occurs when pollutants enter the groundwater from sources such as agricultural runoff, industrial waste, and sewage.
  • It can cause contamination of drinking water supplies and lead to serious health problems.
  • It can also have long-term impacts on aquatic ecosystems and biodiversity.

Understanding the causes and effects of groundwater pollution is essential for protecting our environment and ensuring safe drinking water for all.

Have you ever been afraid about the quality of water where you live?

Have you ever turned on your faucet and smelled a strange odor or even seen something yucky in your tap water?

Do you catch yourself wondering now and then just how healthy your municipal water really is?

Unfortunately, when it comes to water quality problems, ignorance isn’t always bliss. If you go through your life drinking tap water without paying much attention to what might be in it, you run the risk of letting the pollution of ground water in your area make you and your family sick.

In this article, you’ll learn all about the pollution of underground water and what it means for you. You’ll be given a brief rundown of the difference between a contaminant and a pollutant so you can better understand the water quality reports for your city or county, and you’ll learn the definition of groundwater pollution and where it comes from.

You’ll also find some examples of groundwater pollution in the real world, and you’ll see just what’s being done about this problem in a handful of different countries. The more you learn about groundwater pollution, the better prepared you’ll be to find out how you can make a difference in your own country, state, city, or county. You’ll be better able to recognize problems that could contribute to this type of pollution in your own home, too.

To learn more, just read on.

Groundwater Pollution vs. Groundwater Contamination

So what is groundwater pollution? Before you can delve into what this term really means, it’s first important to understand what makes a pollutant and what doesn’t. Groundwater pollution comes from a lot of different places and can be found almost everywhere around the world. Below, you’ll be introduced to several examples of pollution as well as a few examples of contaminants. Keep in mind that just because water has levels of contaminants present in a given sample doesn’t mean that water is polluted. Contaminants aren’t always dangerous, especially in lower numbers. A pollutant is a contaminant that is always dangerous.

contaminant groundwater


Examples of Pollution

  • Pesticide chemicals – Chemicals that are used in pesticides are some of the biggest pollutants of groundwater around the world. Similarly, household cleaning chemicals, insecticides, rodent poisons, and other chemicals you might find in a residential neighborhood cause the same problem. Any time these chemicals are present, they run the risk of leaking and spilling into the soil, which puts them just a step away from polluting the groundwater there.
  • Radioactive waste – Especially in areas near nuclear power plants, radioactive waste can be a potential pollutant of groundwater. This waste is dumped, either purposefully or accidentally, and seeps into the soil toward groundwater.
  • Oil – When oil spills take place, the environment suffers seriously, and groundwater is no exception to this. Although surface water is generally more threatened by oil than groundwater is, it’s still very possible for traces of oil to turn up in groundwater samples.
  • Bacteria – Although some levels of bacteria are normal, and some are even good, when bacteria pollute groundwater this can cause serious problems. Widespread outbreaks of serious illness are almost always attributed to polluted groundwater that’s filled with bacteria. E. coli, hepatitis, dengue fever, dysentery and many other diseases are caused by polluted groundwater.
  • Parasites – Parasites are very similar to bacteria in their presence in groundwater. When they contaminate the groundwater in a given area, the people in that area are exposed to dangerous organisms that can enter their intestines and do a lot of harm.

Examples of Contamination

  • Aluminum – Aluminum can be found naturally in rocks, which are often exposed by mining operations. When too much aluminum is present in water, it can lead to sluggishness, chronic fatigue, and memory problems. However, in small amounts, aluminum in the water is a normal contaminant.
  • Iron – Iron is another common groundwater contaminant that isn’t necessarily a pollutant if it’s present in small numbers. This is a naturally-occurring mineral that often comes from rust. Too much iron in the body can damage the liver.
  • Copper – Copper can be found naturally in rocks that are exposed from mining activity as well. In small amounts, copper in the water isn’t much of a problem, although it can be damaging to fish. It’s an essential element in human life in very small amounts, but too much can cause serious digestive problems and kidney dysfunction.
  • Fluoride – Fluoride occurs naturally like the other elements listed here, but it’s also added to municipal water to help strengthen bones and teeth. Too much of it can damage teeth, and very high amounts can seriously calcify bones and lead to terrible pain and irreversible damage.
  • Nitrates – Nitrates are a naturally occurring contaminant present in the water near mineral deposits. They can also be found in animal waste, so fertilizer dumping leads to too many nitrates in water supplies. When nitrates are high, the environment suffers.

What Is Groundwater Pollution?

All that information is very helpful, but what is ground water pollution anyway? Of course, it’s important to be able to recognize problem areas like pollutants and understand that some contaminants are necessary and natural, but identifying groundwater pollution further is an important next step to take toward truly understanding the problem.

what is ground water pollution


Groundwater itself is simply the water that can be found underground. This doesn’t include surface bodies of water, but instead includes the water that fills in spaces between sand, rocks, and soil beneath the surface of the earth. 30% of the freshwater on the face of the earth is stored as groundwater. To put this in perspective, almost 69% of the earth’s freshwater makes up glaciers and ice caps, while only one percent can be found as surface freshwater sources like rivers and lakes.

With numbers like that, you can see why groundwater is so important!

Where does it Come From?

Groundwater comes from a process called the hydrologic cycle. This is the same cycle that has been providing water to the planet through the earth’s whole life. The first step in the cycle is the evaporation of surface water. When this water evaporates, vapor makes its way into clouds. These clouds travel some distance and then cause precipitation in the form of rain or snow.

When it rains or snows on the ground, some of this precipitation immediately refills surface water. However, a lot of it falls on the soil. When that happens, this water seeps through small cracks in the rock, dirt, and sand (called aquifers) to reach the water table beneath the surface of the planet. This recharges the groundwater there.

From there, groundwater slowly trickles through the water table and eventually reaches lakes, rivers, and other surface freshwater sources. It recharges these bodies of water so that they are filled with liquid that can once again evaporate into clouds and continue the hydrologic cycle. This is the basis for weather on our planet, and it’s been happening for a very long time.

How does it Affect Us?

  • Environmental – Groundwater is incredibly important to the environment, as you can see by the cycle explained above. Without groundwater, there’s no way for surface bodies of fresh water to recharge, and this leads to drought. It also leads to a destruction of wetlands and rainforests, both of which rely on this cycle to keep them functioning.
  • Human Health – Polluted groundwater can cause major problems for human health. This is one of the most common ways diseases are spread, but polluted groundwater can also cause potential poisoning from heavy metals present in the water.
  • Water Strain – When groundwater isn’t as available as it should be in a given area, this puts a lot of strain of water in the area. This can lead to bans on water use and a general lack of enough water to sustain life well.
  • Economic Changes – In areas where groundwater pollution is strong, cities are abandoned and factories aren’t able to operate properly anymore. The economy in these places suffers greatly, and sometimes it never completely recovers. Tourism also decreases, especially in places where disease outbreaks have occurred from water pollution.

Potential Sources of Groundwater Pollution

Now you’ve had a crash course in pollutants versus contaminants, and you’ve learned a few examples of each. You’ve also found out just what groundwater is, and why its pollution affects us all. In this section, you’ll further explore groundwater pollution by examining different potential sources that can cause it. Remember that some areas and parts of the world don’t have to deal with all of these problems equally, but that every part of the world faces at least one of these at some point. Groundwater pollution is a problem everywhere, and no place is completely free from it.

definition of groundwater pollution


  • Mining – Water is a necessary part of most mining operations. However, when water is used for mining, it almost inevitably gets exposed to harsh heavy metals present in the rock. This wastewater can then easily spill, leak, or run into nearby groundwater. Mines that have been abandoned may be used for waste dumping, which further contaminates the groundwater and can lead this water to be collected by wells in the area.
  • Landfills – Landfills are a huge pollution problem. When plastics, batteries, printer ink, electronics, and many other items are left to sit in landfills without moving for a long time, they leach chemicals into the soil. These chemicals find their way into groundwater and can cause serious harm to human and animal life both.
  • Accidents – Of course, accidents happen, but they could be prevented in many situations by increased assessments and stricter regulations on chemical and fuel storage and transportation. When oil, gasoline, or chemicals spill or leak, they reach groundwater quickly and can be impossible to remove completely.
  • Hazardous Waste – Once again, proper storage and upkeep could keep hazardous waste from polluting groundwater in all but the most extreme disaster circumstances. Most of the time, this type of pollution comes from illegal dumping of waste or wastewater. It also comes from waste that hasn’t been stored or disposed of in a safe way.
  • Pipelines – Sometimes, pipelines that haven’t been installed correctly can cause pollutants to seep into groundwater. For example, if a sewage pipeline is installed wrong or becomes worn down over time, human waste can leak out of it into the surrounding soil. This can spread disease, bacteria, and even parasites to the groundwater there.
  • Agriculture – Most agricultural operations contribute to groundwater pollution, even though groundwater makes up the majority of water used for crop irrigation. Pesticides, fertilizers, and even animal waste cause serious groundwater issues in places where agriculture is very common, especially in rural parts of the United States and the rest of the world.

Examples of Groundwater Pollutants

So what are some of the most common types of groundwater pollutants you might come across in your area? You might be surprised at just how serious some of the most mundane of substances can be when they reach groundwater supplies. Check out this list of ten types of groundwater pollutants, and then take a look around your home, yard, and neighborhood. Do you see any ways you could improve the state of groundwater by simply removing some of these items from around your home?

1. Natural Substances

We’ve already talked a little bit about natural substances and how they can affect the groundwater supply in a given area. However, we haven’t yet mentioned lead and arsenic, which are two of the most commonly-occurring of these natural substances that can cause a lot of harm to humans and animals both. In levels that are higher than just trace amounts, both of these substances can lead to poisoning that can, in turn, lead to death.

2. Human or Animal Feces and Urine

In the wild, natural sources of water are often polluted or at least contaminated with animal feces and urine. However, when these contaminants reach higher numbers, they become a serious problem for anyone who might be drinking from these water supplies. These waste products often contain ammonia, bacteria, and parasites that can all negatively impact humans without proper filtration. Luckily, it’s easy to filter these substances out of the water with modern technology. However, this continues to be a problem in developing countries that don’t have access to this technology.

3. Pesticides

Once again, we’ve already talked about how pesticides can affect groundwater. They continue to be one of the biggest problems of groundwater pollution in the world today, in developing and developed countries alike.

4. Oil

Even when oil spills don’t take place, there’s still a big problem of groundwater pollution related to oil. When oil leaks or seeps into the soil, it quickly reaches the water table. However, the frequent use of oil and gasoline both can contribute to air pollution, which in turn leads to water pollution when it rains. When fossil fuels are absorbed into clouds and then deposited later by rain onto soil, that soil becomes polluted with those substances even if it’s far away from the place where the pollution began.

5. Road and Natural Salt

Road salts are used in many large cities to keep drivers safe when the roads are icy and slick. However, when the snow melts and that salt is carried off the roads by trickling water, it frequently finds its way into groundwater sources in the area. Salt is also a problem in places where mining has taken place because natural salt deposits are exposed to fresh groundwater. Although salt in itself isn’t a pollutant, when it is present in high levels in water, it leads to high salinity that affects the environment and makes the water unusable by humans.

6. Battery Acid

You might not realize it, but battery acid is a big problem of groundwater pollution too. Especially in landfills, battery acid leaks into the soil and pollutes groundwater every day. When this happens, the acid is carried to drinking water sources and may even end up in tap water in some circumstances. This is a dangerous substance that harms the environment and can damage human digestive systems if it makes it that far.

7. Radon

Radon comes from nuclear processes, especially near power plants. It shouldn’t be present in water at all, and if it is, that water is very dangerous for human use. It can cause cancer if consumed regularly, and it can seriously deform animals in the surrounding area. Radon is often present in groundwater surrounding places where nuclear processes take place. Some studies have shown that people living in cities and villages where radon pollution is high have a much higher rate of cancer in both children and adults.

8. Household Cleaners

One of the leading causes of groundwater pollution in residential neighborhoods is the overuse of household cleaners. These cleaners are made up of many different types of harsh chemicals, none of which are good for the environment. At the very least, when they leak or are washed into the yard, they can damage your plants and grass and may make your pets sick. However, in many situations, they find their way into groundwater and can even seep into your own home through its individual pipelines. When this happens, the chemicals don’t move through the municipal water treatment facility first, and so your family ends up drinking these harsh cleaners right out of the tap.

9. Bacteria

The general catch-all term “bacteria” refers to the many bacteria and pesticides that can and do affect groundwater daily. Almost every source of groundwater is exposed to bacteria, but in small numbers, they aren’t too dangerous. It’s only when bacteria get out of hand that water becomes polluted. Unfortunately, this happens more often than not, especially in places where fertilizer is used often or animals are allowed to defecate on the land without regular cleanup.

10. Toxic Runoff

Last but not least, toxic runoff can lead to major groundwater pollution issues as well. Factories, agricultural sites, construction sites, and even residential communities all contribute to toxic runoff in some way. Any place that uses chemicals on a regular basis has the potential to cause runoff. When it rains, these chemicals are picked up by the rainwater and carried into the soil. If these sites are very close to surface water sources, the chemicals may be carried directly into the water instead. Either way, they can build up quickly.

Real Effects of Groundwater Pollution

In order to really understand just how serious groundwater pollution is, for both humans and the environment, you should examine some real-world examples of true groundwater pollution stories. Although there are a lot of other situations where groundwater pollution caused widespread problems, these are five that you might not have heard of before. They show just how brutal polluted groundwater can really be, and how impossible it can sometimes be to clean up completely, even after decades.

pollution of underground water


  • Walkerton, Canada – In May of 2000, the city of Walkerton in Ontario, Canada was plagued by a terrible E. coli outbreak that stemmed from groundwater contamination in the area. When dozens of residents of the city suddenly became afflicted with symptoms of E. coli, the water supply was immediately tested and found to contain this dangerous type of bacteria. However, the water was deemed safe, and people kept using it for days. Eventually, seven people died and over two thousand became very sick. The employees of the local water company who claimed the water was safe to drink were found guilty of wrongdoing.
  • Weifang, China – In 2013, Weifang in the Shandong Province of China saw a serious groundwater pollution event come to light as well. It’s no secret that paper mills and chemical production facilities in the area have been pumping wastewater into underground wells, but even though the groundwater is polluted in this part of the country, there’s almost no way to actually catch the culprits in the act. Therefore, although this all came to a head a few years ago, nothing has been done about it as of yet, and residents continue to drink polluted groundwater.
  • Lanzhou, China – Also in China, this time in Lanzhou in the Gansu Province, benzene pollution in groundwater has become a serious problem. As recently as 2014, huge levels of benzene have turned up in water samples in this city. Too much of this chemical in the blood can cause trouble with the production of blood in the body, and it can also lead to cancer. It’s believed that this groundwater pollution came from pipeline leaks that resulted from explosions at a nearby chemical company.
  • Kesterson Wildlife Refuge – In a sad twist of fate, the Kesterson Wildlife Refuge, which was built to be a safe place for threatened and endangered wetland species to survive and thrive, turned out to be a serious pollution disaster that took place in California in the 1980s. This artificially-constructed wetland was irrigated from farms in the area, which unfortunately led to a huge buildup of selenium, a common contaminant that only pollutes water when it’s present in high levels. Animals and fish that lived in this artificial wetland ended up deformed and often died quickly because of selenium poisoning.
  • Merriespruit Mine Slick – In Merriespruit in South Africa, a 1994 groundwater pollution event took place. One of the dams in a mine located in Merriespruit broke, which allowed 2.5 million tons of wastewater tailings to wash into the nearby mining village. Unfortunately, this led to the death of seventeen people and the destruction of almost 300 houses, but it also contaminated the groundwater in the area with heavy metals and toxins found in the mine.

How Groundwater Pollution is Being Addressed

Although all these groundwater disasters might make it seem as though the state of groundwater around the world is pretty hopeless, don’t worry. This issue is being heavily addressed in a lot of different ways in countries around the world. While it’s true that not every country is on board just yet with protecting groundwater sources, more and more are beginning to understand just how important this precious resource really is. Here are just some of the ways groundwater pollution is being addressed today.

examples of groundwater pollution


  • Ground Water Rule – In the United States, the Ground Water Rule was enacted in 2006. This rule comes from the Environmental Protection Agency and focuses on improving the quality of drinking water by preventing and cleaning up groundwater pollution. It specifically focuses on fecal contamination and the spread of disease and parasites through bacteria and microorganisms that might be polluting groundwater sources. Right now, the rule is applicable to public water sources but not necessarily to private wells.
  • Underground Injection Control Program – Also in the United States, the Underground Injection Control Program was first brought about in 1974 as part of the Safe Drinking Water Act. It provides regulations and requirements for waste injection wells. This means that it’s not possible to simply deposit wastewater underground without proper permitting, and doing so illegally can lead to hefty fines and other types of punishments. This type of dumping is only permissible in areas where groundwater contamination isn’t going to take place.
  • Industrial Water Law – In Japan, the 1987 Industrial Water Law regulates the use of groundwater for industrial production and operational processes. Basically, it rations groundwater use and makes it illegal to use groundwater from areas where the water levels are already very low. It also makes it illegal to use groundwater from places where the water is heavily polluted and needs to be cleaned up.
  • Groundwater Daughter Directive – In the United Kingdom, this 2006 act works to protect groundwater and cut back on the amount of pollution taking place throughout several countries. It regulates the frequent assessment of groundwater and enforces testing to be sure chemical and bacteria levels are low enough for human consumption. When pollutants are found in high levels in any water sample, this directive mobilizes efforts to find out why and to take care of the problem as quickly as possible.
  • Pesticide Regulations – In individual states throughout the United States, pesticide regulations are being enforced more and more in order to keep these harsh chemicals from affecting groundwater sources. In California, Groundwater Protection Areas have been identified, and agricultural and other types of processes are strictly regulated in these places. Whenever possible, alternate methods of operations and waste management are encouraged in places where groundwater is protected.


Have you learned a lot about groundwater pollution since we got started? By now, you should be well acquainted with the whole concept of groundwater pollution and just what it means for you and the rest of the world. You’ve learned the definition of groundwater, and you know how to recognize its pollution when you see it. You can even tell the difference between a pollutant and a contaminant in many situations, and you should be ready to get out there and start making a difference if you want to try.

You’ve also learned about some real instances of groundwater contamination and pollution that are still affecting the environment and human beings both around the world. While you’ve been able to read up on some of the ways a few countries are trying to improve the state of their groundwater, you might feel as though the place where you live isn’t doing quite enough yet. That’s a normal feeling, and it’s probably accurate, too.

If you feel like your city, county, state, or even country could be doing more to clean up groundwater and prevent its pollution in the future, don’t be afraid to reach out and start campaigning for changes in your area. It may be a little intimidating the first time you get in touch with a governor, mayor, or president of a company, but after a while you’ll feel so comfortable in your knowledge of groundwater pollution issues that you’ll be ready to address anyone you need to talk to in order to make some changes.


5 Essential Tips to Avoid Groundwater Pollution

  1. Reduce the use of fertilizers and pesticides in agricultural activities, as these can seep into groundwater.
  2. Properly dispose of hazardous materials such as motor oil, paint, and cleaning products to avoid them from entering the water supply.
  3. Avoid dumping any kind of waste into storm drains or streams, as this will eventually end up in groundwater.
  4. Be mindful of what you flush down your toilet. Only human waste and toilet paper should be flushed down the drain.
  5. Check for leaks in your plumbing system regularly to prevent wastewater from entering the groundwater.

ALSO: Consider installing a rain barrel to collect rainwater for use in gardening and other outdoor activities. This will help reduce the amount of water that is drawn from local aquifers!</p

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About The Author

Carolyn Rodriguez
Research Writer
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Carolyn Rodriguez works at AllAboutWaterFilters as a content research writer, specializing in content resources regarding water pollution, contamination, and treatment. She has previously worked as an editing assistant, content production assistant, research assistant, and ghost writer for a range of websites, with a particular concentration on water pollution. She is currently writing regularly for AllAboutWaterFilters as well as her own water safety essays across the web.

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