Causes and Effects of Water Contamination: Your Ultimate Guide

Have you ever wondered what causes water contamination where you live?

Are you worried about the effects this contamination might have on you and your family?

Do you feel like you have a lot to learn about water contamination but aren’t sure where to get started?

If you’re in search of information about what causes water contamination and how it can affect you and the world around you, this article is here to help. In the first part of this article, you’ll discover what water contamination is and how you can recognize it. From there, it should be easy to move on to the next two sections, where you can learn about this issue even more in-depth.

As you learn about these problems, keep your eyes peeled for potential sources that might show up in your area. Whether there’s a cause of water contamination in your own home or one in your neighborhood, when you have the right information to help you, you’ll be able to locate these problem areas before they get to be too serious.

While you’re examining the place where you live, remember the potential effects you’ll learn about in this article too. They can range from simple to very serious, and keeping them in mind is a good way to help you remember to take note of problem areas in your neighborhood.

The more you learn about water contamination overall, the better you’ll be able to make some changes for the greater good of the water in your part of the world. Read on to discover more.

What is Water Contamination?

The first step in understanding water contamination causes and effects is learning just how to properly define water contamination in the first place. There are differences between contamination and pollution, and there are a few specifics you need to know in order to continue learning:

cause of water contamination

What is the difference between water contamination and water pollution?

These two words might seem like they mean the same thing, but there’s a slight difference. Water contamination refers to any situation in which water contains something other than water. Only pure water can be considered free of any contaminants. Even when water contains trace amounts of salt or minerals, it’s technically contaminated. As you can see, contamination isn’t always a bad thing, even though the connotation of the term implies that it is. Contamination may be something as simple as hard water in your tap or as significant as E. coli outbreaks.

How much contamination must be present for pollution to occur?

Basically, there is a cutoff point at which water contamination becomes water pollution. It all has to do with the amount and severity of the contaminant present in the water. For example, trace amounts of copper are actually beneficial in water, and many treatment facilities will add this to fresh water to provide some much-needed nutrients to the people who drink it. However, if copper is present at higher levels, it can seriously poison anyone who comes into contact with this water. Only when copper is present in a high enough quantity does it become a pollutant instead of a contaminant.

Which areas are at the greatest risk for water contamination?

Although we all face water contamination regularly, there are some places where it’s more of a concern than others. For example, anywhere unsanitary conditions are present, the water is much more likely to be contaminated with bacteria, parasites, viruses, and more. People who live downstream from factories are more likely to experience contamination from chemicals and waste, while anyone living in a rural community near a lot of farms may be at greater risk for contamination from chemical pesticides.

Now that you have a basic framework of understanding about water contamination, it’s time to move on to learning about its causes and effects. Remember that water contamination is a problem we all face, but that in some parts of the country and the world, you may experience worse contamination situations than you would elsewhere. Keep your eyes open and take notice of potential problems in your area.

Causes of Water Contamination

There are a lot of different causes of contamination of water, and they come from a variety of different sources. Different types of water contamination can cause specific types of problems, and some causes of contamination may also be causes of pollution. However, no matter what aspect of water contamination you’re looking into, you can expect to see some of the same patterns occurring over and over again throughout its many causes.


Groundwater is the most important type of water on the planet. This is a resource we often overuse without realizing it, but it’s one we desperately need to protect. We use groundwater every time we drill a well or pump water from an unseen source for any purpose.

  • Groundwater pollution is often caused by substances that seep through the soil into the water table below. Although many people are unfamiliar with groundwater, it’s actually where we get the vast majority of our fresh drinking water from around the world. This is the water that’s stored beneath the surface of the planet. Although this might sound as though it’s more protected than surface water, the opposite is often true.
  • Groundwater is much more seriously threatened than surface water in the world today.
  • This type of pollution leads to serious complications in much of our drinking water. Because of the hydrologic cycle, groundwater eventually ends up recharging surface freshwater sources with more water. This is what keeps them from running dry, but when groundwater suffers, these surface water sources do too. Unfortunately, this means that whatever pollutants are present in groundwater eventually find their way to our drinking water.

Surface Water

Although surface water isn’t used as regularly as groundwater, it’s still vastly important and needs to be protected as well. Surface water includes both fresh and saltwater sources, but for the purposes of this article, we’ll be focusing mostly on freshwater.

reason for water contamination
  • Surface water pollution is often caused by dumping. Surface water is the opposite of groundwater. It’s any water you can see on the surface of the planet, including lakes, rivers, ponds, streams, springs, and even the ocean. Freshwater pollution affects surface water sources quite a lot, but not as much as it affects groundwater.
  • Surface water isn’t used for drinking very often, but when it is, it’s often contaminated or polluted by substances present in the groundwater that recharges it.
  • This type of pollution leads to further complications down the line. When surface water is polluted or contaminated, it eventually evaporates into the atmosphere as part of the hydrologic cycle. When this happens, it takes the contaminants in the water with it. Clouds form and carry those contaminants across long distances to be deposited on the earth once again as rain. From there, the contaminants soak into the groundwater and the whole contamination situation begins again.


Rainwater is collected in cisterns and used for a variety of purposes. Even when it isn’t collected, it still falls naturally and waters crops, refills surface water sources, and can potentially carry contaminants with it.

  • Rainwater pollution is caused by the evaporation of polluted water as part of the hydrologic cycle. As discussed above, contaminated surface water evaporates and becomes contaminated rainwater. This can be carried for a long time before it falls on a new location. This is also how acid rain is formed.
  • Although we don’t use rainwater for drinking very often, this type of contamination can seriously affect people who do rely on cisterns to get their water. While this is more common in developing countries now than it is in the United States, there are still people in rural communities who use this water for farming, gardening, washing, and even sometimes drinking. More and more factories are beginning to use rainwater for industrial processes as well.


Direct reasons for the contamination of water are those that can clearly be linked to a specific type or instance of contamination. Tracing back a type of contamination may lead to a general problem (“too much lead in the water”), but it may also lead to a specific cause (“a construction site dumping lead-laced wastewater”). These specific problems are direct causes of contamination.

  • Sewage and septic systems – When sewage and septic systems leak or are improperly installed, they can be direct causes of water contamination from human waste. As waste products seep out of these damaged pipes, they end up in groundwater nearby, where they contaminate it with bacteria almost instantly.
  • Construction sites – Construction sites cause a lot of runoff that directly affects both ground and surface water. These sites rarely take precautions against chemical runoff, and unfortunately, this means that every time it rains, they’re contaminating the water in the surrounding area.
  • Leaks and spills – These direct causes of contamination may be accidental, but that doesn’t make them any less troubling. A lot of times, they could have been prevented by better attention to detail, more thorough assessments, and more frequent maintenance. Whatever causes these events to occur, however, they can always be pointed to as a direct cause of any serious contamination issues.


Perhaps not surprisingly, indirect causes of water pollution are those that don’t have specific situations they can be traced back to. These are more general, and while they’re major problems that need to be addressed, they don’t always have clear-cut solutions like direct causes often do.

  • Factory dumping – Factories dump chemicals and wastewater into freshwater sources all the time. This is generally not legal anymore, but it still happens because there are plenty of loopholes and opportunities for them to get around regulations that have been put in place. Although we can usually look at contaminated water supplies and say factory dumping must have caused the contaminants present, we can’t say for sure which factories or when it happened. Therefore, this is an indirect cause of contamination.
  • Agricultural sites – Agricultural sites are like construction sites in that runoff is a huge part of what makes them a contamination cause. However, unlike individual construction sites, it’s harder to pinpoint which farm or even which practice might contribute to contamination in the area. Pesticide contamination is a major problem that affects a lot of rural water sources, but it comes from almost every farm in a given area.
  • Landfills – Runoff occurs at landfills, too, and so does groundwater contamination from plastics, batteries, and other chemical-heavy products that have been improperly disposed of in these locations. It’s crucial to recycle plastics whenever possible and always take batteries of any kind to a recycling facility. Even printer ink can be so full of toxic chemicals that it may build up in landfills over time and lead to chemical contamination of groundwater.


Manmade causes of water contamination are either items that have been created by humans or substances that occur as part of processes performed by humans. If you don’t think you’d come across it in a body of water in the woods, then it’s probably not a manmade contaminant. Anything chemical and anything that ends up in a landfill is a manmade contaminant.

reason for contamination of water
  • Hazardous waste – This can come from just about anything, but it usually comes from industrial processes. Many different types of factories have dangerous waste materials as their byproducts, and unfortunately, they often dump them in surface water or on soil that absorbs them into the groundwater below.
  • Chemical dumping – This is very similar to hazardous waste. Chemicals used in industrial processes as well as in the fuel industry are often dumped in much the same way, which leads to serious contamination problems. Chemical dumping isn’t as rampant as it once was, but we are all still feeling the effects of the past when this was a common activity. Chemicals that were dumped as long ago as the 1940s are still turning up in water supplies today and may even be responsible for some of the worse contamination issues in the country.
  • Road salts – Although salt is a natural substance, road salts are used by humans, which makes them a manmade contaminant. When road salts are used to melt ice on frozen roadways, they are eventually carried into nearby soil and surface water through melting ice. From there, it doesn’t take them long to contaminant these water sources with increased salinity, which can be fatal to freshwater fish and plants.


Natural reasons for water contamination occur whether humans are involved or not. Sometimes they may be removed through water treatment, but other times they may be too severe for simple fixes. Think of natural causes of water contamination as something you might encounter in water from a stream or pond on a hiking, camping, or even spelunking adventure.

  • Heavy metals – These include lead, arsenic, magnesium, copper, iron, and other metals that may be beneficial in some small amounts but can be toxic in larger quantities. These metals are often present in natural rock formations, and even the most organic sources of water may contain trace amounts simply from passing over these metallic rocks. However, in some instances—sometimes due to human intervention and sometimes not—the water becomes more exposed to these metals, which causes it to become severely contaminated.
  • Animal waste – Once again, this is something that’s sure to be present in organic, natural water sources. Any body of water out in the woods has been frequented by several animals who have urinated and defecated in it. This is a type of natural contaminant that can be easily removed by water treatment facilities and usually by portable water filters, too.
  • Nitrates – Nitrate contamination is a major issue in the world today. While nitrates can be introduced into water through agricultural processes, they also occur naturally. Anywhere fish live, nitrate levels will rise simply because of the waste produced by the fish. It’s only when these levels climb that nitrates become a problem. This can happen in some instances naturally, even without the use of fertilizer and pesticides that usually lead to nitrate contamination.
  • Radioactive – Last but not least, radioactive material may occur naturally in some contaminated water. Like heavy metals, substances like radon gas sometimes occur in nature and may find their way into water sources. Like almost every other type of natural contaminant, however, this may also be caused by human interaction with water sources.

Effects of Water Contamination

The effects of water contamination are, for the most part, not quite as extreme as those related to water pollution, but they may be very similar. Contamination does have the potential to cause a lot of serious issues just like pollution does, and it’s in these effects where the two really show their differences. Where pollution is always sure to cause a lot of widespread damage and destruction, contamination’s effects are sometimes subtler than that.


Health effects are by far the most widely-noted problem associated with water contamination. When water contamination issues make the news, they’re almost always associated with health risks. This is just one reason why it’s vital to pay attention to boil water advisories in your area and to avoid your tap water if you’re told to.

  • Bacteria – The bacteria that can be present in contaminated water range from beneficial to deadly, and the severity of each bacterial contamination situation differs from one to the next. Serious bacteria present in water can cause illnesses like typhoid, cholera, dysentery, hepatitis, E. coli contamination, and much more. This is much more common in places where conditions are very unsanitary and water isn’t sent to a treatment facility before it’s used in taps, such as in developing countries. However, in rare instances, this type of contamination can and does occur in the United States, sometimes with deadly results.
  • Parasites – Parasites can easily be found in almost any source of freshwater. They tend to live in water, where they can be easily ingested by humans and animals like. From there, they set up shop in different parts of the body—usually in the digestive system, but not always—and lay their eggs, leading to an infestation of the body in question. Sometimes parasites can exist in human bodies without the slightest indication, but in most situations, they lead to digestive upset, fatigue, fevers, headaches, and sometimes much more serious health effects. Some parasitic contamination can lead to death, especially in young children and in the elderly.
  • Viruses – Viruses aren’t a lot different from bacteria in water supplies, and they can lead to many of the same problems. Widespread illnesses, outbreaks, and epidemics can almost always be traced back to virus or bacteria contamination in water sources. Once again, this is more common in unsanitary conditions than in places where water is treated, but it’s not exclusive to these locations.
  • Heavy metals – When heavy metals are present in drinking water, they can cause anything from an upset stomach to seizures and coma depending on their severity. Most of the time, the results fall somewhere in between, including vomiting, diarrhea, dehydration, and high fever. These substances can also lead to rashes and other types of skin irritation if they’re present in water used for recreational purposes, like swimming pools or lakes where fishing and sports commonly take place.


While pollution usually has more of an effect on the environment than contamination does, there are still several water contamination effects brought about in terms of the natural world. Sometimes, the effects of contamination on the environment may be hard to notice until they’re too extreme to do anything about. This is why it’s crucial for government organizations as well as concerned nonprofit groups to keep a close eye on the quality of water in the environment, even if it’s not water humans will be drinking.

  • Chemicals – When chemicals build up in environmental water sources, they can quickly kill the life that relies on that water to be fresh. Rivers where wastewater and chemical dumping from factories have become the norm see a lot of fish death as a result of this introduction of harsh chemicals into an otherwise natural environment. Of course, when fish die, so do the animals and birds that eat them. In some extreme situations, chemicals have even caused insect populations in nature to suffer, which has an even greater effect on the animals that exist in these areas. Everything is connected, and when the water is contaminated, the creatures that live in and around it will suffer.
  • Runoff – Toxic runoff from factories, agricultural sites, construction sites, and landfills can all cause contamination that seriously damages the environment. This type of runoff can kill plant life very quickly, leaving the ground bare and the trees dead and drying up. Serious runoff contamination in surface water sources can start to kill off fish, insects, and birds as well.
  • Nutrient poisoning – Like runoff and chemical contaminants, nutrient poisoning can cause fish death, too. However, another side effect of nutrient contamination and poisoning is a buildup of these nutrients in fish that continue to survive. While they might not die off, they’ll become contaminated themselves, and then anyone who eats them will suffer from the same type of contamination. This is a huge contributing factor in heavy metal poisoning and toxicity from fish that have been caught in natural locations (as opposed to being raised in fisheries).
  • Nitrates – Nitrates are a very serious problem that many people don’t recognize. Nitrates are a factor of natural waste products, so anywhere waste (be it human or animal) is present in water, that water is bound to have an increased level of nitrates. Many of us have been drinking water contaminated with too many nitrates most of our lives, but young children, the elderly, and immunocompromised people may be the ones feeling the effects most significantly. Nitrates can also cause blue baby syndrome, which is a serious and often fatal condition suffered by young infants.


Water contamination can seriously affect the economy in places where it’s very prevalent. While the widespread effects of contamination may go well beyond the economy, this is one area in which humans will notice these effects the most. Anyone who relies on clean water for work may suffer greatly from major contamination events. Here are just a few of the ways this problem can get out of hand quickly in terms of the economy.

fishing on a polluted water
  • Housing – When water contamination occurs in a given area, that area is sure to see some changes in terms of housing and real estate almost right away. For example, if a serious contamination incident occurs in a city, people are likely to move away from that city if it doesn’t get cleaned up soon. Even if few people leave, no one new will be willing to move in if they know the water is seriously contaminated. Even if the water has been cleaned up, sometimes the stigma associated with a place where contamination caused big problems can be enough to keep new residents away. The value of homes will decrease in this situation, and real estate will suffer.
  • Tourism – Places that rely on their natural or manmade water sources to draw in tourists have a lot to lose when that water gets contaminated. No one wants to visit a lake that’s known to contain high levels of lead, for example, so the economy in the town surrounding it suffers as fewer and fewer people book hotel rooms, visit local restaurants, and buy gas from gas stations in the area. Even water parks can be doomed by contaminants. River Country, a water park once a part of Walt Disney World, even had to close down due to parasitic and bacterial contaminants in the water.
  • Fishing – The fishing industry has already taken a huge hit from pollution and contamination both, and that doesn’t seem to be changing anytime soon. People who fish for a living have found the number of potential fish for them to catch dwindling more and more over the past several years because of contamination in fresh bodies of water. This shift in the economy affects people who buy fish for restaurants, people who eat at those restaurants, the communities surrounding them, and so on.


Now that you’ve finished reading, you should feel a lot better about your understanding of the causes of water contamination and its effects, too. You should have a good idea of what water contamination is (and what it isn’t), as well as how to recognize it when you come across it. You understand the many different problems that you might encounter in your own neighborhood or when traveling throughout the country and beyond. And of course, you now have plenty of knowledge about the effects that you run the risk of encountering on a daily basis no matter where you are.

So what now? This is a lot of information to think about, and it’s an excellent start. However, there’s plenty more to learn about water contamination as well as pollution. If you’re interested in finding out more, there are tons of articles that can help you get started. As you learn, you may feel inspired to start making changes around your home, your community, your workplace, and even around the world. If you feel the urge to improve the quality of water where you live or for people in developing countries, that’s great! There are plenty of ways you can get involved and start making a difference right away.

The effects of water contamination and pollution are felt around the world. When you pitch in to help prevent and clean up these problems, you’re doing something to help everyone—not just yourself.