Types of Drinking Water Contaminants and How To Remove Them

Posted by
John Woodard on September 04, 2023

No matter where you live or where your water comes from, some form of contamination resides in your tap or well. Whether your water is high in arsenic, bacteria, chlorine, or other impurities, there is a filtration system that will suit your needs. With proper filtration in place, you can experience the health benefits and refreshing taste of clean water. Below you can find information on the types of common contaminants that inhabit water, how they enter water supplies, and how to remove them from your home’s tap or well.

What are the categories of contaminants in drinking water?

The EPA divides contaminants that inhabit drinking water into two main categories:

  • Primary contaminants are detrimental to health. Contaminants included in this category are microorganisms, radionuclides, disinfectants, inorganics, and organics.
  • Secondary contaminants are aesthetically displeasing but not unhealthy to consume. These include fluoride, iron, chloride, aluminum, copper, and manganese.

What is in tap water?

Microorganisms, heavy metals, secondary contaminants, and organic compounds are all regulated in tap water by the EPA, but they are still present in small amounts. However, some contaminants, like heavy metals, can enter tap water between being treated and reaching your home. Old or corroded pipes can cause lead or copper to leach into water and contaminating your tap. To treat microorganisms, chlorine is added to city water and can greatly affect the taste and odor of your tap water. To know exactly what contaminants are in your tap water, you can use a water testing kit.

filling water glass

How do I remove contaminants from drinking water?

You can remove contaminants from drinking water with either a filter or another type of water treatment system. Common filtration systems and other devices for removing contaminants from water include the following:

Each system type specializes in removing different contaminants, and some are best used in conjunction with other systems. Below you can find what systems are best for removing specific categories of contaminants.

Additionally, some contaminants can be reduced by exposure to specialized filter media engineered to reduce and eliminate specific contaminants. For example, anthracite is a coal used to eliminate turbidity and sediment from water, and is often used in conjunction with other media. Template-assisted-crystallization (TAC) media is used in hard water applications to prevent scale. Activated alumina is a filter media used to reduce contaminants like fluoride and arsenic from water.  These contaminant-specific media can often be found in specialty water filter cartridges and water filtration systems.

How to remove microorganisms from drinking water

What are microorganisms?

Microorganisms, as defined by the EPA, are primary contaminants that include bacteria, viruses, and pathogens that can carry waterborne illnesses. Some examples of bacteria and cysts common in water are E. coli, Legionella, Giardia, and Cryptosporidium. Consumption of microorganisms results in symptoms such as diarrhea, vomiting, headaches, fatigue, and death in extreme cases. The EPA sets strict standards for microorganisms in city-treated water, so microorganisms are almost exclusively a concern with well water.

You can remove microorganisms from water with a UV purification system. UV systems, rather than passing water through a filter media, subject water to ultraviolet light that prevents bacteria from reproducing. Since microorganisms are so small, filter media may remove some of them, but many are too small to be trapped by a filter media’s pores. To be effective against most bacteria, a filter media needs a micron rating of .3 or less. A UV filter eliminates all microorganisms from water with UV light, not by passing water through a filter. As a result, you can have peace of mind that bacteria is not slipping through a filter media.

Learn more: What is a UV Water Purifier and How Does It Work?

If you do not have access to a UV water purifier and need to remove microorganisms immediately, you can boil your water. Boiling is effective because it damages structural components of microorganisms that help them thrive. A boil water advisory will be issued in your municipality if there is a pathogen risk in your tap water. If your water contains high levels of other contaminants, such as lead or arsenic, boiling will not make the water safe to drink. In fact, boiling raises the concentrations of these contaminants as water is lost in the form of steam.

Learn more: Boil Water Advisory Procedures

How to remove inorganic compounds from drinking water

What are inorganic compounds in water?

Inorganic compounds comprise of many types of contaminants, and some are best reduced by different filtration systems than others. Common inorganic compounds found in water supplies are:

  • Heavy metals
  • Chlorine
  • Fluoride
Heavy metals in drinking water

Heavy metals refer to any metallic element with both a high density and toxicity. They include mercury, lead, arsenic, and copper. Copper and lead can contaminate water through corroded pipe in old homes. Mercury, on the other hand, most often enters water supplies through rain and snowfall collecting mercury in the air. Arsenic can enter a water supply through natural deposits and agricultural waste. If heavy metals are present in high enough concentrations in drinking water, consuming them causes symptoms such as increased cancer risk, nausea, abdominal pain, and shortness of breath.

The most effective way to filter heavy metals from water is a combination of a water softener and RO system. While RO systems eliminate minerals that cause water hardness, the elements can clog the membrane and make it less efficient. Adding a water softener to a filtration system before the RO system will increase the efficiency and lifespan of the RO membrane.

Learn more: How to Remove Arsenic from Water | How to Remove Copper from Water

Chlorine in drinking water

Chlorine is abundant in city water supplies because it is added to eliminate bacteria. However, chlorine affects water’s taste and odor, and an abundance of chlorine is harmful to your health. Consuming too much chlorine can cause blurred vision, chest tightness, burning sensations, and shortness of breath. To be healthy to drink, water should contain less than 4 parts per million of chlorine.

Chlorine levels are reduced in water by most filtration methods. RO systems, distillers, ultrafiltration systems, and activated carbon filters all reduce chlorine. The easiest and cheapest method of removing chlorine from water is a simply carbon filter like the one found in your refrigerator. If you wish to primarily remove foul tastes and odors from water, an under-sink carbon filter is a great option for you. Whole-house carbon filters and upflow catalytic carbon systems are perfect for you if you wish to reduce chlorine in all water coming into your home. One of the three stages of an RO filter is a carbon core that eliminates chlorine and other odor-causing chemicals. Ultrafiltration systems remove almost the same contaminants as an RO system, but they retain beneficial minerals such as calcium and magnesium in the filtered water. Distillers are a valid option in apartments or other places where you do not have means to add a point-of-use water filtration system.

Learn more: Reverse Osmosis vs. Ultrafiltration

Fluoride in drinking water

Fluoride is added to city water supplies for its oral health benefits. However, there is controversy surrounding the effects that consuming fluoride has on health. The maximum level of fluoride considered safe to drink by the EPA is 4 parts per million, and the optimal level of fluoride in drinking water to prevent tooth decay is 0.7 parts per million. Consuming unsafe levels of fluoride can cause abdominal pain, abnormal tastes in the mouth, headache, and eye irritation.

The most popular ways to reduce fluoride levels in water are reverse osmosis systems and distillers. RO systems are typically point-of-use systems, meaning they attach to a faucet or other single output. Distillers, on the other hand, are countertop filtration systems that require energy to heat the water. While RO systems are faster and require less upkeep, distillers are excellent if you do not have means to add a filtration system to your home or apartment.

Learn more: How to Remove Fluoride from Water

How to remove organic compounds from drinking water

What are organic compounds found in water?

Volatile organic compounds (VOCs) are organic compounds with low boiling points that are present in drinking water and air. They come from both man-made and natural products, such as paint, gasoline, pesticides, cleaning products, and air fresheners. Most VOCs enter water supplies through improper disposal. They then leach through the soil until they reach groundwater.

VOCs are best removed with an activated carbon filter. Carbon filters use adsorption to cling contaminants to the filter media as water passes through it. Since VOCs are organic, they are carbon-based. This makes carbon filters particularly effective at removing VOCs from water. Carbon filters will not only remove VOCs from drinking water, but they will remove foul tastes and odors as well. The EPA sets standards for VOC concentrations in city-treated water, so VOCs are a greater threat to well water than tap water.

Learn more: Activated Carbon Filters 101 | What are VOCs and How Do You Remove Them?

How to remove secondary contaminants from drinking water

What are secondary contaminants?

The category of secondary contaminants refers to multiple elements, and they are best filtered with different methods. Secondary contaminants negatively affect water in three ways:

  • Aesthetically
  • Cosmetically
  • Technically

Aesthetic effects include foul tastes and odors, while cosmetic effects do not pose a health risk but are still not desirable in water. Technical effects of secondary contaminants include damaging machinery and causing filtration systems to be less efficient. Some elements that cause these effects are:

  • Iron
  • Sulfur
  • Aluminum


Iron is one of the most common contaminants found in well water. While it is not unhealthy to consume, it does cause unsightly stains, bad tastes, and inefficiencies in filtration systems. Multiple types of iron inhabit water, and they are all treated differently.

Ferric iron is iron that has not completely dissolved within water. Sediment filters are best for trapping ferric iron as it passes through the filter media. To guarantee that ferric iron will be caught, ensure that your sediment filter has a small enough micron rating.

Ferrous iron is iron that has completely dissolved within water. Water softeners can remove this iron at low levels, but other methods are needed if iron is present in high concentrations. Manganese greensand, KDF filter cartridges, and birm are all alternative methods to water softeners for ferrous iron. Manganese greensand is an oxidizing filter that converts ferrous iron to ferric iron so that it can more easily be removed. Birm oxidizes iron in water with elevated pH levels. KDF filters are not only effective removing iron, but they also remove high levels of chlorine and heavy metals.

Bacterial iron occurs when bacteria has bonded with iron molecules. It most commonly inhabits wells that are poorly maintained or neglected. Bacterial iron can clog the insides of pumps, pipes, and plumbing fixtures if given the opportunity to flourish. It can be reduced by a process called shock chlorination. This process involves introducing high levels of chlorine into the well that eliminate the bacteria bound to the iron. Once the bacteria are gone, a water softener, oxidizer, or sediment filter can reduce iron in the water.

Learn more: How To Remove Iron from Well Water | 5 Benefits to Removing Iron from Water


Sulfur is a pungent element that tarnishes the smell and taste of water. It is most popular for its rotten egg stench and bitter taste. Consuming sulfur is not dangerous except in amounts of 500 parts per million or greater. For most water supplies, the main issue is not the danger of sulfur intake, but rather its unpleasant effects on water.

Sulfur levels can be reduced in water by activated carbon filters, distillers, RO systems, and ultrafiltration systems. Carbon filters’ primary function is to eliminate foul tastes and odors from water. Because of this, most refrigerator filters are activated carbon filters. RO and ultrafiltration systems are both systems that can be attached to your home, making them a hassle-free method of removing sulfur and many other contaminants. Distillers also reduce sulfur levels because the sulfur does not evaporate at the same temperature as water.


Aluminum is a metal that is known for its light weight yet high durability. It is an abundant element in the earth’s crust, so it can be found it many water supplies. Consuming aluminum in moderate levels is not seen as detrimental by the EPA. In concentrations of above 0.2 parts per million, aluminum can cause little discoloration in water, but it will not affect the odor or taste. The most effective ways to reduce aluminum in water are reverse osmosis systems and distillers. Alongside all their other benefits, both RO filters and distillers remove more than 98% of aluminum from water.

water going down drain

How to remove emerging contaminants from drinking water

The most effective ways of removing emerging contaminants from water are reverse osmosis and ultrafiltration. The term emerging contaminants refers to personal care products that manage to contaminate the water supply. This most commonly occurs in the form of runoff, where contaminants enter surface water and eventually flow into groundwater. Emerging contaminants are tricky because products that make their way into water are always changing. The EPA is researching the effects of emerging contaminants and how to prevent them, but for now the effects are mostly unknown. Because of the mystery behind emerging contaminants, RO and ultrafiltration systems are popular because they reduce a vast majority of contaminants from water.

How to remove PFAS from water

PFAS, short for "per-and polyfluoroalkyl substances", are chemicals used in industrial applications, such as packaging, clothing, furniture, and electronics. These chemicals are formed by a bond between carbon and fluorine, one of the strongest combinations possible. Because PFAS are so strong, they resist deterioration and earned themselves the nickname "forever chemicals." The Environmental Working Group determined that over 200 million Americans may have PFAS in their drinking water, and, because PFAS resist deterioration, they are hazardous to the body. Some side effects to PFAS exposure include liver and kidney damage, thyroid problems, increased cholesterol, and cancer.

The safe level for EPAS set by the EPA is 70 parts per trillion (ppt). 70 ppt is a health advisory guideline set by the EPA, so municipalities are not required to eliminate PFAS below this level. Since PFAS is a fairly new issue, the EPA is continuously working to learn more about the effects they have on the human body and how to safely reduce them from water supplies.

The best systems for removing PFAS from water are reverse osmosis, activated carbon, and ion exchange. Reverse osmosis systems are one of the most comprehensive filtration systems available and reduce a vast majority of contaminants. Activated carbon filters reduce PFAS levels by a process called adsorption. The chemicals cling to the carbon core as water is passed through. Finally, ion exchange systems reduce PFAS levels by exchanging negative ions with positive ones via an anion resin.

Is contaminated water safe for uses other than drinking?

Contaminated water may be safe for uses other than drinking, but that ultimately depends on the contaminants in the water and what the water is used for. Some contaminants can soak into skin more easily than others or are dangerous enough that accidental consumption can be hazardous toward health.

Can I shower in contaminated water?

If you wish to shower in the contaminated water, contaminants that do not easily absorb in the skin, such as arsenic, do not pose a threat except in high concentrations (500 parts per billion or greater). Such high concentrations are only a risk if you get your water from a well, not from city water. Bacteria-infested water is safe to shower in as long as no water is consumed, so children are at a greater risk because they are more likely to swallow water in the shower.

Filters designed specifically for showers exist, but they are primarily used to remove chlorine and other components of tap water. These filters prevent chemicals and contaminants from negatively affecting hair and skin health.

Can I garden with contaminated water?

You can garden with contaminated water if the plants are inedible and the contaminants in the water do not harm the plants, but we do not recommend gardening with contaminated water at all. Plants soak up many contaminants from water, so they can spread to you if the plants are edible. Not only is contaminated water detrimental to your health, but plant health suffers as well. Using contaminated water on plants can lead to leaf discoloration, irregular growth, and plant death. Certain plants, such as lettuce leaves and radish roots, can take in E. coli from water and spread it to the consumer.

Tap water contains salts and chemicals that are detrimental to plant health, so using filtered water is a better option. You can test exactly what contaminants reside in your water with a water testing kit. A garden water filtration system will help you water your plants without the burden of contamination.



If you have any additional questions about contaminants or water filtration systems, please don’t hesitate to contact our experts or visit our blog.


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