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Most Common Drinking Water Contaminants Explained: What are the categories & types?

What are the most common drinking water contaminants


Whether you’re surveying the news or scrolling through social media newsfeed, you come across the headlines of water quality concerns in areas around the country. How often do we believe the massive host of impurities in the tap when drinking water? And, what could be these contaminants or what risk they pose?

A study showed that Over 286 million Americans get their tap water from a community system. This tap water contains million of contaminants, and out of 286 million, you could be the one who has contaminants in your drinking water. So, it’s compulsory to know what your water contains?

In this blog, you’ll come to know what type of most common contaminants are present in your drinking water, their risk, and how to treat them. Keep continuing to read!

Types of Drinking Water Contaminants

Contaminant Candidate List (CCL) and Regulatory Determination of EPA explained categories of Drinking Water Contaminants. Additionally, understanding the drinking water contaminants as Primary, Secondary, and Emerging was included up to safety standards, and treatment methodologies that are enforced by law, implemented to protect public health.

Categories of Drinking Water Contaminants

According to the Safe Drinking Water Act, “A physical, chemical, biological, or radiological substance or a matter present in drinking water is known as a Contaminant.” Drinking water contaminants may be poisonous or dangerous to health if consumed at certain levels in drinking water, while some can be harmless. 

After investigation and lab test analysis, it is found that there are four major categories of contaminants:

Physical contaminants are the contaminants that change the physical property of the water. Examples include sediments and organic materials suspended in lakes, rivers, and streams.

Chemical contaminants are the contaminants that are naturally occurring or artificial. Examples include pesticides, nitrogen, metals, toxins excreted by bacteria, and pharmaceuticals.

Biological contaminants are the contaminants due to organisms in the water. They are also known as microbes for microbiological contaminants. Examples include protozoans, bacteria, viruses, and parasites.

Radiological contaminants are chemical substances with an unstable number of protons & neutrons that make the atom unstable and release ionizing radiation. Examples of radiological contaminants include plutonium, cesium, and uranium.

Primary, Secondary, and Emerging Water Contamination

Here are common primary, secondary, and emerging most common contaminants in drinking water.

Primary Water Contamination

The EPA’s NPDWR has concerned the treatments and standards enforceable by ordinance and planned to control the contaminant levels in drinking water to protect public health. These contaminants could be microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals, radionuclides.

ContaminantsHealth Effects Source
CryptosporidiumGI disturbanceHuman & animal fecal waste
Giardia lambliaGI disturbanceHuman & animal fecal waste
LegionellaLegionnaire’s or pneumonia diseaseNaturally occurring
Total Coliforms  it’s harmful to healthPresent Naturally and fecal and E. coli come from human & animal fecal waste.
Viruses (enteric)GI issuesHuman & animal fecal waste

Contaminant Health Effects Sources 
Bromate cancer riskA byproduct of drinking water disinfection
ChloriteAnemia, Nervous issuesA byproduct of drinking water disinfection
Haloacetic acids (HAA5)Cancer riskA byproduct of drinking water disinfection
Total Trihalomethanes (TTHMs)Liver, kidney disordersA byproduct of drinking water disinfection

ContaminantHealth EffectsSources
ChloraminesEye or nose irritation, stomach issuesWater additive
ChlorineEye/nose irritation, stomach issuesWater additive 

ContaminantHealth EffectsSources
AntimonyIncrease in blood cholesterol; decrease in blood sugarDischarge from petroleum refineries; fire retardants; ceramics; electronics; solder
ArsenicSkin damage, cancer issuesErosion of natural deposits
CopperGastrointestinal distress after short term exposure Liver or kidney damage after long term exposureCorrosion
FluorideBone disease, dental and skeletal fluorosisWater additive,  naturally occurring
LeadDelays in physical or mental development in infants and children Adults: Kidney problems; high blood pressureCorrosion 
NitrateShortness of breath and blue-baby syndrome.Fertilizer 
Nitrite (measured as Nitrogen) Shortness of breath and blue-baby syndrome.Fertilizer

Secondary Water Contamination

The National Secondary Drinking Water Regulations have reported further contaminants not deemed a health risk at certain levels. The EPA set the mandatory water quality standards and, by law, enforced as Maximum Contamination level, which are designated to safeguard public health against the consumption of drinking contaminants. Further, it is given that the EPA has included standard levels for 15 contaminants in the National Secondary Drinking Water Regulations and does not implement these as “Secondary Maximum Contaminant Levels”. 

Even though secondary impurities aren’t supposed to be dangerous, they destroy the water quality. The guidelines for SMCL are to aid public water systems in handling their water for aesthetic concerns, such as taste, color, and odor. These contaminants are not considered to present a risk to human health. Area-wise testing is done for them on a volunteer basis. 

ContaminantsStandard LevelsEffects
Aluminum0.05 to 0.2 mg/Lcolored water
Chloride250 mg/Lsalty taste
Copper1.0 mg/Lmetallic taste
Fluoride2.0 mg/Ltooth discoloration
Foaming agents0.5 mg/Lcloudy appearance
Iron0.3 mg/Lrusty appearance
Manganese0.05 mg/Lblack to brown appearance, our article will help you remove manganese cheaply
Silver0.1 mg/Lskin discoloration
Sulfate250 mg/Lsalty taste
Total Dissolved Solids (TDS)500 mg/Lhardness
Zinc5 mg/Lmetallic taste
According to the EPA, Secondary Drinking Water Standards For Nuisance Chemicals are mentioned in the table

Emerging Water Contamination

Contaminants of emerging concern (CECs) include harmful chemicals in water endocrine disruptors, pharmaceuticals, personal care products, and other combinations that can negatively affect public health. 

  • Pharmaceuticals
  • Personal Care Products (PCPs)
  • Polyfluoroalkyl substances (PFAS)

What are the most common drinking water contaminants? 

The United States is facing a crisis regarding the availability of pure drinking water. As water rushes through streams, rivers, lakes, oceans, and filters across rocks, it comes into contact with all and makes the water contaminated. The truth is that the source of water sources is full of dangerous chemicals. There are various most common contaminants found that is needed to be filtered out.


Nitrates are the most common impurity found in fertilizers, manures, and liquid waste from septic tanks and plumbing systems, particularly in rural areas.

Drinking nitrate water at high levels can be dangerous, particularly for infants, as it can direct to methemoglobinemia or “baby blue” disorder. The safe level for drinking water nitrates is 10 parts per million (ppm), and the above is unsafe.


Lead pipes, faucets, and fixtures are the common sources of lead in drinking water. Environmental Protection Agency (EPA) has reported the lead level in public drinking water is 15 ug/L (15 micrograms per liter). Excess of it can be detrimental. There are so many natural ways to remove lead you can opt for it.


Arsenic is a naturally metallic substance found in minute amounts.

Studies on arsenic have revealed that it can cause health effects such as numbness in the feet or hands, discoloration of the skin, digestive problems, and skin cancers. High arsenic levels are reduced by using the best water filters to remove arsenic

Protozoans, Bacteria, and Viruses

Most bacteria, protozoans, and viruses get into the water and cause different diseases. The common bacteria in drinking water are  Escherichia Coli, Campylobacter Jejuni, Giardia Lamblia, Salmonella, and Legionella Pneumophilia.

Useful Links

The organisms such as E.Coli and Legionella Pneumophilia can damage health. Use our links to remove common bacteria in drinking water such as coliform, amoeba, and other microbes through reverse osmosis.

How To Get Rid of Coliform Bacteria

Reverse osmosis remove amoebas

Reverse osmosis remove bacteria


Fluoride is an organic mineral within the earth’s soil and is reported as a helpful additive for water sources to help against tooth decay. Extreme concentrations can cause fluorosis and many other issues. You can effectively reduce high arsenic levels by using fluoride water filters.

Other Most Common Waterborne Contaminants

Our senses do not notice microbial and organic contaminations. But the water involved in agricultural areas may have harmful microbial and organic contaminants. Chemicals from fertilizers and pesticides increase the risk of diseases.

According to the research, 485 000 diarrhoeal deaths each year are estimated. It is presented as half of the world’s population will suffer from stress areas. Most common waterborne contaminants include Aluminum, Ammonia, Barium, Cadmium, Chloramine, Chromium, Copper, Mercury, Perchlorate, Radium, Selenium, Silver, Bacteria, viruses, and Uranium. Diseases caused by drinking contaminated water such as

  • Diarrhea
  • Cholera
  • Dysentery
  • Typhoid
  • Polio
  • Increase cancer risk
  • Reproductive problems 
  • Impair eye
  • Liver& kidney disorder

Effects of Contaminated Water on Human Health

The US EPA recommended the standards for 80+ contaminants that pose a risk to human health. Acute and chronic are the two effects caused by drinking contaminated water.

When a person takes contaminant for hours or days in a high amount, the effects are “Acute“. Water contamination examples include microbes, bacteria, and viruses. Additionally, when a person takes contaminants level over the EPA’s safety standards for the long term, the effects are “Chronic“. Water contamination examples such as disinfection byproducts, radionuclides, and minerals.

According to research, Thirty-five metals are involved in a hazard to human health. Studies report that 23 out of them are heavy metals, and according to the International Agency for Research on Cancer (IARC), arsenic and cadmium are carcinogenic. Antimony causes heart problems and cholesterol issues. Lead causes anemic diseases, neurological, reproductive, renal, hematopoietic, cardiovascular, musculoskeletal, while Mercury involves liver damage, and Copper was reported for distracting gastrointestinal issues. 

Treating Drinking Water Contaminants

Every problem has a solution. Similarly, the most common contaminants in drinking water are a big issue for the United States and other countries. Contaminants are removed by treating or filtering tap water depending upon the types of contaminated water. The main reason for US water contamination is discharge and chemicals from agriculture as rainwater runs through fields and other water bodies and adds to wells or taps.

If I notice that, why is my well water yellow? I will come to the point that something makes our water yellow. Different microbes, chemicals, iron, and manganese, can be the reason. The most reason for yellow water is iron, and it can be filtered out by using whole house iron water filters. They are reliable and cost-effective to use and install at your homes to get safe, pure, and healthy water.

Microbes, viruses, bacteria, and protozoans can also be treated using reverse osmosis water and UV technology. My best suggestion is to install a Waterdrop RO filter that uses a UV mechanism to eradicate them. 

Removal of heavy metals is an essential part of healthy drinking. Treatment for these heavy metals included chemical precipitation, physical separation, ion exchange, RO membrane, and distillation.

Some contaminants are removed using catalytic carbon filters, while some are removed using the ion-exchange methodology. But if we discuss overall as an expert and my research says that a hundred problems but only one solution is “Reverse Osmosis Filtration”. RO can make the water acidic you can install an alkaline filter to prevent mineral-free water. 

Installing the water filters is not difficult because the technology has grown. You can install these products according to your peace and comfort. Reverse osmosis systems with tankless systems are also available with minimum maintenance.

The renters facing difficulty getting contaminant-free water can benefit from RO water filters for apartments. Moreover, whole home RO filters are also available for well water with RO technology by which you can get purified water from all over the house.


In a verdict, I would like to say, test your water before drinking to determine which impurity it contains. Protect yourself and your family from the exposure. Treat the drinking water with appropriate methods to stay safe. For more information about filters, contact BestFiltersLife.

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