Well Water Contamination and Its Symptoms

About 13 percent of Americans receive their drinking water from a private well. Unlike those that receive city-treated water, homeowners that use well water must regularly test their water supply for contamination. Because many contaminants are colorless, odorless, and tasteless, well water may be neglected by homeowners that rely on their senses to detect contamination. However, checking the safety of your well water is critical in ensuring the long-term health of each person in your household. Below you can find information about common well water contaminants, how to detect them, their symptoms, and how to treat water that is contaminated.

Common well water contaminants

The most common contaminants in well water include iron, lead, arsenic, bacteria, volatile organic compounds (VOCs), nitrates, and fluoride. Some of these contaminants are more concerning than others, but all should be dealt with before the water enters your home.


Iron is one of the most common contaminants found in well water in the United States. It enters groundwater by seeping through the earth’s crust and into soil, where it can be dissolved by rainwater. Iron is also the most common element in the earth’s crust, making it particularly troublesome for well owners.

Signs of iron in well water

Iron gives water a dark color, foul odor, and harsh metallic taste. It can also leave red, brown, and orange stains on appliances and fixtures, clog pipes, and discolor skin, hair, dishes, cookware, and laundry. The EPA regulates iron as a secondary contaminant. This category refers to contamination that does not affect a person’s health, but rather the aesthetic qualities of water. The EPA standard for iron in drinking water is 0.3 parts per million, or 300 parts per billion.

Symptoms of iron in well water

Drinking iron at extremely high concentrations can cause side effects, but most levels of iron consumption are not harmful to the body. Symptoms of excessive iron consumption include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Stomach pain

You will notice the physical signs of iron in your home before you suffer side effects in your body. As a result, most homeowners do not suffer from excess iron intake because they treat the iron when it impacts their homes initially.

How to treat iron in well water

There are three types of iron found in water: ferric, ferrous, and bacterial iron. Each of these types requires different treatment, so you will need to discover which type of iron is contaminating your well before deciding on a treatment option.

Ferric iron is iron that is not completely dissolved in water. It makes water appear red or brown when it comes out of your faucet. This type of iron can be reduced by a sediment filter or a reverse osmosis (RO) system. RO systems contain a sediment filter that eliminates iron before it can damage the RO membrane, making RO an excellent treatment option for ferric iron.

Ferrous iron is completely dissolved in water, making it trickier to remove than ferric iron. It does not change the appearance of running water, but it will turn water a red or brown color after standing. The most effective way to remove ferrous iron is with a water softener. Water softeners are often paired with reverse osmosis systems to remove as much contamination as possible, particularly in well water systems.

Bacterial iron is not harmful in itself, but it can create an environment for harmful bacteria to grow. It is normally yellow or brown, but sometimes it does not alter the color of water. The most effective way to remove bacterial iron, as well as any other bacteria, from your well is shock chlorination. This involves adding chlorine to your well to kill any bacteria. This is similar to the process used by city water treatment plants to make water microbiologically safe.


Lead is a toxic metal that is most abundant in the Southeast and Northeast United States. The New England states, Alabama, Georgia, and South Carolina are the country’s most susceptible regions to lead contamination in well water. The least vulnerable states to lead are North Dakota, South Dakota, Wyoming, Montana, Colorado, and Nebraska, but wells in all states have potential for lead contamination.

Signs of lead in well water

Lead can make water appear darker, or it may not change its appearance at all. Lead-contaminated water may also contain small particles visible to the naked eye. Most of the time, however, lead cannot be detected by sight, smell, or taste, so the only way to know if your water contains lead is by testing.

Symptoms of lead in well water

Lead consumption at any level can produce some nasty side effects, including:

  • High blood pressure
  • Joint and muscle pain
  • Headaches
  • Birth defects and miscarriage
  • Fertility issues
  • Abdominal pain
  • Constipation
  • Altered brain development in children

These side effects are symptoms of what is known as lead poisoning. There is no antidote to lead poisoning, so exposed persons should remove the source of lead from their environment and wait for their body to rid itself of the toxin. Lead consumption is particularly dangerous for children as it affects the development of the brain.

How to treat lead in well water

Lead can be removed from water with either a reverse osmosis system or certain types of activated carbon filters. If you need to remove lead from your water, ensure that the activated carbon filter you purchase is NSF certified to remove lead. These filters are specifically designed to treat lead, and other carbon filters will not reduce lead levels in your water.


Arsenic is famous for its poisonous reputation, so its presence in water should not be taken lightly. Arsenic occurs naturally in groundwater and soil in the Southwest, West, Midwest, and Northeast United States. In these regions, the likelihood of arsenic levels exceeding the EPA-recommended 10 parts per billion (ppb) is significant. Arsenic levels below 10 ppb can still cause symptoms over prolonged exposure, so all wells should be tested for arsenic contamination at least once.

Signs of arsenic in well water

You cannot see, smell, or taste arsenic in water. Symptoms often result from exposure to arsenic over a long period of time, so checking your well for arsenic is crucial in preventing these side effects. Vigilantly monitoring your water composition with well water testing kits can provide insight into contaminants like arsenic that otherwise may remain undetected.

Symptoms of arsenic consumption

Arsenic can produce undesirable side effects if consumed in high concentrations or even low concentrations over time. These symptoms include:

  • Increased cancer risk
  • Thickening and discoloration of the skin
  • Nausea
  • Vomiting
  • Diarrhea
  • Numbness in extremities
  • Partial paralysis
  • Blindness

How to treat arsenic in well water

The best treatment option for removing arsenic before it enters your home is a reverse osmosis (RO) filtration system. In addition to reducing arsenic levels in water, RO systems significantly decrease essentially all other contaminants as well.


Bacteria are the most important contaminant to remove from your well water because of their immediate effect on the body after consumption. Not only do they impact the body immediately, but they can also cause severe symptoms in old, young, and immunocompromised individuals.

The most common type of bacteria found in well water is coliform bacteria, which can be broken down into the categories total coliform and fecal coliform. Total coliform is not dangerous in itself, but its presence may mean that fecal coliform has contaminated your water supply. Fecal coliform, whose main species is E. coli, can enter a water supply from yards, farms, pastures, and any other location where animal waste deposits into the ground. Fecal coliform can also be introduced by creatures entering the well or a leaking septic system.

Signs of bacteria in well water

Bacteria are often not detectable in water because they are colorless and microscopic. If fecal coliform levels are high enough, you may detect a slight color change in your water. In most situations, you will not notice bacteria in your water until you get it tested or suffer the side effects of bacteria consumption. To combat bacterial infestation, have your well checked every six months for the presence of bacteria. However, due to their exposure to organic material and the elements, most wells require some form of bacteria pretreatment, like a UV purification system. This ensures that no matter the conditions, the water you bring into your home is safe to consume and free from pathogens, viruses, and other harmful bacteria.

Symptoms of bacteria in well water

If bacteria reside in your well water, you will likely become ill a few hours to a few days after consuming it. Waterborne illnesses often stem from drinking contaminated well water. The symptoms of these illnesses include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal cramps
  • Fever
  • Fatigue
  • Headaches

How to treat bacteria in well water

Bacteria in a well can be treated as it enters your home or in the well itself. Some filtration systems deactivate the bacteria, and others remove them from the water entirely.

To deactivate the bacteria, use a UV water purifier.

To reduce the levels of bacteria in the water, use an ultrafiltration or reverse osmosis system. These should be used as an additional step after UV purification, and should not be relied upon to do the bulk of bacteria neutralization.

To treat the well itself, you will need to perform a process called shock chlorination. It involves adding chlorine to the water and pumping it through the system to eliminate the presence of bacteria.

Volatile organic compounds

Volatile organic compounds (VOCs) are a common industrial groundwater contaminant in California, Florida, Nevada, New England, and mid-Atlantic regions of the United States. VOCs reach groundwater through industrial waste, leaks, spills, or improper disposal of items containing these chemicals. VOCs easily evaporate into a gas and are dangerous to inhale after they vaporize.

Signs of VOCs in well water

VOCs dissolve in water and oftentimes do not alter its color, smell, or taste. As a result, the only way to discover the presence of VOCs is to have your well tested. A well should be tested for VOCs once every three to five years, but consider testing more often if you live near a landfill. Landfills contain products with VOCs that can leak these chemicals into groundwater in high concentrations. If your well water is contaminated with VOCs, do not cook or drink with the water until the VOCs are treated. Because they vaporize in the air, VOCs are particularly harmful when water is boiled and the chemicals are inhaled.

Symptoms of VOC consumption

Exposure to VOCs can lead to some adverse symptoms, including:

  • Damage to the nervous system, liver, and kidneys
  • Eye, nose, and throat irritation
  • Headaches
  • Fatigue
  • Vertigo
  • Nausea
  • Dyspnea

How to treat VOCs in well water

Carbon filters are the most effective treatment option for removing VOCs from water. However, be sure to check that the carbon filter you are installing is rated and tested to remove VOCs, as not all carbon filters are engineered for such purposes. Reverse osmosis systems with a carbon pre-filter or postfilter will remove VOCs and an abundance of other contaminants as well. A whole-house reverse osmosis system will protect your water from VOCs, most bacteria, metals, arsenic, and many other contaminants.


Nitrates are a groundwater contaminant most commonly caused by agricultural waste. Fertilizer and animal manure are the leading contributors to nitrate contamination, meaning it is often a more rural issue than an urban one. Septic system leaks and industrial waste are also contributing factors to nitrate contamination. The four states with the highest groundwater nitrate levels are California, Arizona, Pennsylvania, and New Jersey. Nitrates can be found in any state, so you should test for it regardless of location. The EPA standard for nitrate levels in drinking water is 10 parts per million (ppm), and a well should be tested at least once a year for this contaminant.

Signs of nitrates in well water

Nitrate cannot be detected in water by smell, sight, or taste. Healthy adults oftentimes do not experience side effects from nitrate consumption, so testing your water can protect those vulnerable to the adverse side effects of nitrate contamination.

Symptoms of nitrate consumption

Nitrates affect how the blood carries oxygen around the body. As a result, nitrate consumption is particularly harmful to young children, pregnant women, and the elderly. The symptoms of drinking water with nitrate contamination include:

  • Blue baby syndrome
  • Birth defects
  • Thyroid issues
  • Increased cancer risk
  • High heart rate
  • Fatigue
  • Weakness
  • Vertigo

How to treat nitrates in well water

Reverse osmosis and ion exchange are the two most effective ways to reduce nitrate levels in a whole-home system. The most common ion exchange systems are water softeners, and they are often used in conjunction with a reverse osmosis system. A reverse osmosis system will reduce nitrate levels in your water by about 83 to 92 percent.


Fluoride has long been a controversial additive in city-treated water, but it is also a naturally occurring contaminant in wells across the United States. Fluoride is added to municipal water supplies to aid oral health, and it is beneficial when the optimal amount is consumed. The EPA safe level for fluoride in drinking water is 4 ppm. Consuming water with more than 4 ppm of fluoride can lead to undesirable symptoms.

Signs of fluoride in well water

Fluoride does not affect the taste, smell, or color of water. This makes it a suitable additive to water at safe levels, but it also makes it undetectable by the senses at high concentrations. According to the North Carolina Department of Health and Human Services, fluoride levels should be checked in a well about once every two years.

Symptoms of fluoride consumption

While fluoride is good for your oral health, consuming too much can lead to tooth problems and other ill side effects. Symptoms of consuming too much fluoride include:

  • Tooth discoloration and decay
  • Neurological problems
  • High blood pressure
  • Skin irritation
  • Seizures
  • Weakness in the joints
  • Increased risk of bone fractures

How to treat fluoride in well water

The most effective treatment option for removing fluoride is a reverse osmosis system. Some other common filtration options, such as ultrafiltration systems and activated carbon filters, do not remove fluoride.

How to test well water

To check for most contaminants in well water, a water sample must be sent to a laboratory for testing. The EPA certifies laboratories in each state for accuracy of test results for homeowners who wish to get their water tested. Common contaminants, such as chlorine and water hardness, can be tested by using a simple water test kit. Other contaminants, such as VOCs, fluoride, and bacteria, must be sent to a lab for accurate results.

Contaminants that are a result of agricultural and industrial byproducts should be tested for regularly, while contaminants that are the result of natural deposits do not need to be tested for as often. Arsenic, for example, almost exclusively enters groundwater through natural deposits, so most homeowners only need to test for arsenic in their well once. Nitrates, VOCs, and bacteria, on the other hand, are regularly introduced into groundwater by agricultural and industrial waste, forcing them to be tested for more frequently.


Posted by John Woodard on December 02, 2022

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