When we turn on the tap, we trust that the water coming out of it is safe, but that’s not always the case.

Everything from agricultural runoff to lead pipes to byproducts of water decontamination can threaten our water’s safety. And the Safe Drinking Water Act that’s supposed to protect our drinking water doesn’t even look for toxic fluorinated compounds known as PFAS chemicals, even though the contaminants have been linked to cancer and birth defects.

That’s why it’s important to understand how these types of contamination happen and what you can do to protect your health and the environment.

Safe Drinking Water Act

The federal government regulates and protects our public drinking water via the Safe Drinking Water Act. The law, which was first enacted in 1974, covers water that comes from public sources, such as rivers, lakes, springs and groundwater wells. It does not cover private wells that provide water to fewer than 25 people.

The Environmental Protection Agency sets national standards for drinking water that include maximum legal limits on more than 90 contaminants. The agency also requires water authorities to perform certain tests for contaminants to ensure the standards are achieved. And it dictates how contaminants should be removed.

States can set their own drinking water standards as long as their standards are at least as strict as the EPA’s requirements. The EPA and states can also take enforcement actions against water systems that violate safety standards.

Types of Contaminants

Numerous types of contaminants can threaten drinking water. They include everything from chemicals to pesticides to animal waste to industrial waste injected into the ground. Naturally occurring substances, such as arsenic, radon and fluoride, can also contaminate groundwater.

Waterborne pathogens, including bacteria, viruses and parasites, can also contaminate water. Between 2013 and 2014, more than three dozen water-related outbreaks were reported to the Centers for Disease Control and Prevention. These outbreaks resulted in more than 1,000 illnesses, 124 hospitalizations and 13 deaths.

According to the CDC, the leading causes of waterborne disease outbreaks are:
  • Giardia
  • Legionella
  • Norovirus
  • Shigella
  • Campylobacter
  • Copper
  • Salmonella
  • Hepatitis A
  • Cryptosporidium
  • E. coli and excessive fluoride (tie)

These contaminants can lead to severe illness, including gastrointestinal upset, neurological problems and reproductive issues. They are especially dangerous to the very young and very old and to those with compromised immune systems.

In recent years, there have also been reports of pharmaceutical drugs in the water supply. Fortunately, the concentrations of these drugs are extremely low and unlikely to cause any considerable health effects, according to a 2012 study by the World Health Organization.

water-related outbreak stat

Causes of Contamination

Agricultural runoff is one of the biggest sources of water pollution and industrial agricultural operations are some of the worst offenders. Crop production and livestock both generate significant amounts of waste and runoff that can seep into water supplies.

Runoff from agricultural operations can contaminate water with:
  • Animal fecal waste containing bacteria, viruses and other pathogens
  • Antibiotics, hormones, salts and heavy metals excreted by livestock
  • Fertilizers, herbicides and pesticides

Water supplies can also be contaminated through the drinking water disinfection process. Water additives, such as chlorine and chloramines, are used to control the growth of microbes. But when levels are too high, they can cause eye and nose irritation, stomach upset and other problems.

Water disinfection can also cause the formation of dangerous byproducts, such as bromates, haloacetic acids and trihalomethanes — all of which can increase your risk of cancer. Other byproducts, such as chlorite, can cause anemia and nervous system problems in babies and children.

Even weather can adversely affect water quality. High temperatures and warmer waters can cause harmful algae blooms. Toxic blue-green algae prefer warm, slow-moving water. They’re also triggered by excessive levels of nutrients, such as nitrogen and phosphorus.

Other potential sources of water contamination include:
  • Industrial activities, such as mining and foundries
  • Runoff from soil, air pollution and automobile emissions
  • Malfunctioning wastewater treatment systems, such as septic tanks
  • Leaking underground storage systems and pipes
  • Landfill leakage
  • Sewer overflows
  • Radiation leaks from nuclear power plants

Water that’s not properly treated or that travels through poorly maintained pipes can also pose a health hazard. If your water is acidic, corrosion of copper and lead pipes can occur and contaminate your water.

That’s what happened in Flint, Michigan in 2014 when city officials decided to start using the Flint River as an alternative water source until a new water pipeline from Lake Huron was built. The new water was cheaper than the water Flint had previously been pumping in from Detroit. But it wasn’t treated with an important anti-corrosive agent to deter lead contamination.

Soon, the city’s water turned brown and consumers began complaining that it was causing skin rashes, hair loss and other problems. Because officials failed to treat the corrosive river water, it was leaching lead out of the city’s aging pipes and sending it through thousands of taps. Studies later revealed that local children’s blood-lead levels had doubled or even tripled in some cases.

What Are PFAS Chemicals?

Perfluoroalkyl and polyfluoroalkyl substances, known as PFAS, are also generating a lot of buzz. The manmade chemicals have been used for decades in everything from non-stick pots and pans to stain protectants on carpets, clothing and upholstery. They are also used in firefighting foams.

The hazardous compounds are sometimes referred to as “forever chemicals” because they don’t break down in nature or in the body. They’ve also been linked to a wide variety of health problems, including several types of cancer, birth defects, endocrine and immune system problems, and elevated cholesterol.

While two common PFAS — perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) — have been phased out by United States industry, they are still used internationally and imported into the country.

A recent study by the Environmental Working Group and Northeastern University’s Social Science Environmental Health Research Institute pinpointed PFAS contamination at locations in 43 states, including drinking water sites serving approximately 19 million people.

Military sites were among those most affected by the problem. The chemicals likely contaminated the environment and groundwater on military bases when flame-resistant firefighting foam was used during training and emergency response exercises.

Communities near manufacturing sites have also discovered high levels of PFAS contamination of their water supplies.

In 2016, the village of Hoosick Falls, New York discovered high levels of the cancer-causing compounds in its public drinking water supply and private drinking water wells. According to the EPA, a person’s exposure level to PFAS, including PFOA and PFOS, in drinking water should not exceed 70 parts per trillion in a lifetime. In Hoosick Falls, some samples detected PFOA levels at 130,000 parts per trillion.

The state of New York has accused two local companies, Saint-Gobain Performance Plastics and Honeywell International, of causing the pollution. Saint-Gobain Performance Plastics was also implicated in a PFOA drinking water contamination near the company’s factory in Merrimack, New Hampshire.

Health Complications of Water Contamination

Contaminated water can cause considerable health problems, ranging from gastrointestinal illnesses to neurological problems to cancer.

In the case of pathogens that cause waterborne disease, the effects are usually noticed rapidly. A person who drinks water containing bacteria or a virus will often develop diarrhea, nausea, vomiting and other acute gastrointestinal symptoms. In severe cases, these symptoms can lead to dehydration and death.

Likewise, ingesting large amounts of copper-contaminated water may cause nausea, vomiting and diarrhea. Extremely high amounts can cause liver and kidney damage and even death.

copper contamination stat

But other types of contamination are more insidious.

Signs and symptoms of lead exposure, for instance, typically won’t appear until dangerous levels have accumulated in a person’s body. The toxic metal can cause lifelong complications. Infants and children exposed to lead may have developmental delays, learning difficulties and behavioral problems.

And the health impacts of PFAS and other contaminants can take years to show up.

Studies suggest that PFAS exposure can lead to:
  • Fertility problems and hormone suppression
  • Pregnancy-induced hypertension and preeclampsia
  • Increased cholesterol levels
  • Immune system problems
  • A disruption of endocrine levels
  • An increased risk of certain cancers, including testicular and kidney cancer
  • Birth defects
  • Liver damage
  • An elevated risk of thyroid disease
  • And increased risk of asthma

Protecting Yourself

If you suspect something is wrong with your tap water, contact your public water utility immediately. You may also wish to have your household water tested. The EPA provides a list of certified laboratories.

Red Flags That Your Water May Be Contaminated
It Looks Funny
Your tap water should always be clear. If it looks cloudy or milky, set it down for a few minutes to see if it clears up. If it does, your water might have just contained trapped air bubbles. If it stays cloudy or foamy, your water could contain elevated levels of heavy minerals or something worse. In that case, it’s time to get your water tested.
It Smells Strange
If your water has an unusual smell, it could be contaminated, but oftentimes contaminants have no smell. A strong rotten egg smell can indicate that your water contains high levels of sulfur. This is usually not dangerous, but it can be unappetizing. Likewise, if your water tastes like a swimming pool, it may contain high levels of chlorine. A water filter may help eliminate excess chlorine and sulfur.
It Tastes Funny
Oftentimes, contaminants have no taste, but in some cases they might. In Flint, Michigan, residents said the water tasted strange, smelled bad and had a brownish color.
contaminated tap water
Your water may be contaminated if it looks, smells, or tastes funny.

According to a 2017 article in the journal Applied Water Science, most contaminants can’t be easily detected and testing is needed to identify them.

If you have reason to believe your water supply is contaminated, switch to using bottled water for cooking, drinking, brushing your teeth and making ice.

In some situations, boiling your water will make it safe to consume. If your water authority issues a boil water advisory, bring your water to a vigorous boil for one minute. This will ensure that all bacteria and other microbes are killed and will make the water safe for drinking, cooking and ice making.

Unfortunately, boiling water won’t get rid of other types of contaminants and may even make the water worse. Boiling water that contains PFAS, for instance, will actually concentrate the chemicals and increase your health risks

On a household basis, there are also a number of things you can do to reduce the pollution of our water.

You and your family can help keep our water supply safe by abiding by the following do’s and don’ts.
  • DO Catch Runoff. Use gravel, paver stones and other porous materials to stop the flow of stormwater around your home before it pours into storm drains.
  • DO Pick Up After Your Dog. Pet waste is laden with bacteria and can easily contaminate storm drains and water supplies. Pick up poop in a recycled bag and put it in your garbage.
  • DO Maintain Your Car. When your car leaks oil, coolant and other fluids, rainwater takes it right into the groundwater. Keep your car in good condition and also wash it in a commercial car wash. It’s better than discharging polluted water down your driveway.
  • DO Shop with Pollution in Mind. Reducing your use of harmful chemicals can also go a long way. When possible, choose non-toxic cleaners and pesticides and opt for phosphate-free detergents.
  • DON’T Use the Toilet as a Trash Can. Don’t flush tampons, baby wipes and other non-biodegradable products. Also avoid flushing old prescription medications and take them to a prescription drug drop-off point instead.
  • DON’T Use the Sink as a Trash Can. Never dump paint, oil or other household chemicals down the drain. This also goes for fat, oil and cooking grease. Instead, keep it in a jar under the sink and dispose of the jar in the garbage when it gets full.

Finally, if you see someone pouring oil down a storm drain or dumping waste in a stream, report them to the authorities. You may first want to try contacting your local government, but if that doesn’t work, you can contact your state environmental agency. The EPA also has an online form where you can report environmental violations.

Last Modified: June 12, 2019

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