How Safe is Our Water? Key Contaminants & Treatment Methods

How Safe Is Our Water? Key Contaminants & Treatment Methods

Water is essential to human health. Every part of our body needs water to function properly: water carries nutrients and oxygen to our cells, removes waste products from our bodies, and helps to regulate our body temperature. In fact, water comprises over 50-70% of our body weight.

The drinking water in the United States is among the safest in the world, in large part due to the requirements established by the 1974 Safe Drinking Water Act (SDWA), which sets protective standards that limit the presence of certain harmful contaminants in our drinking water. Trusting that these regulations are in place, many Americans don’t consider that their drinking water may be contaminated in one way or another. However, a number of threats to optimal water quality still remain. This article delves into some of the ways in which our drinking water can impact our health.

What’s in Our Water?

Water can contain a range of different types of pollutants that can adversely affect our health. Some examples include microorganisms such as Giardia and Legionella; heavy metals such as arsenic and lead; organic chemicals such as benzene; and byproducts from disinfection such as chloroform. Such contaminants can enter our water supply in a variety of ways, from pollution due to industrial activity to corrosion from the water delivery system infrastructure.

When these pollutants are present in our drinking water, they can cause a wide range of health effects, such as gastrointestinal infections, auto-immune disorders, neurological disorders, developmental delays and disabilities, and even cancer.
Currently, there are two main ways in which water pollutants present concerns in the U.S.: our ability to manage known pollutants that we already regulate, and our ability to deal with newly identified pollutants that we learn are harmful as scientific knowledge advances.

The State of Our Water Infrastructure

Even for the contaminants we know about and regulate, we still struggle to effectively filter them out and meet regulatory standards. Every year since 1982, an estimated 4 to 28% of the U.S. population has been affected by health-based violations of the SDWA. According to one analysis, 18,000 U.S. community water systems – serving almost 77 million Americans – violated at least one SDWA rule in 2015, with more than 80,000 total violations. These failures are largely due to poor maintenance of our aging water infrastructure, lack of water testing at point-of-use, and lack of well water regulation.

Funding Limitations

Funding limitations are one major hindrance to maintaining, repairing or upgrading water distribution and sewer systems that are reaching, or have already reached, the end of their intended operational life. In fact, the Environmental Protection Agency (EPA) estimates that over $743 billion are needed for water infrastructure improvements, and the American Society of Civil Engineers (ASCE) gave the U.S. drinking water infrastructure a “C-” grade in 2021, citing its aging and deteriorating infrastructure.

Testing and Regulations

Regulated contaminants can enter water through distribution systems such as piping, and EPA regulations do not include point-of-use testing. Water pipes are often made from lead, and lead can leach into water if the pipes are corroded. While water mains are sometimes replaced, the piping which connects the water main to the home (known as the service line) is usually difficult and expensive for property owners to replace. One analysis found that in 2015, over 18 million people were served by community water systems that violated the

Lead and Copper Rule. Violations included failure to properly test water for lead or conditions leading to lead contamination, and failure to take measures to prevent corrosion.
Lead exposure has been linked to damage to the central and peripheral nervous system, learning disabilities, and in rare cases even death among children, while exposure may cause hypertension, decreased kidney function, and reproductive problems among adults.

Finally, SDWA protections don’t even apply to all water. Around 10% of Americans drink unregulated water (e.g., from wells) that is not subject to SDWA safety standards. While some state and local governments may regulate water from private wells, these regulations vary widely.

Drinking unregulated water may pose additional health risks, as the water may be improperly treated or disinfected and/or may travel through improperly maintained distribution systems, thereby exposing these individuals to higher levels of water contaminants. Giardia is of particular concern as improperly treated or disinfected water sources are more vulnerable to human and/or animal waste contamination.

Covid-19 and Water Contamination

During the Covid-19 pandemic, many buildings such as gyms, offices, and even primary residences have remained unoccupied. Unfortunately, buildings were not designed to withstand prolonged periods of non-use (be it days, months, or years, depending on the building). When they are left unoccupied for long stretches of time, metals such as lead and copper can enter the building’s drinking water due to pipe corrosion.

Regular water use helps to prevent water stagnation by bringing in new water, along with disinfectant substances. Water stagnation is of particular concern as it can alter the chemistry of the water, making it more corrosive over time. This can lead to using up the corrosion-control chemicals that may have been added to the water, further increasing copper and lead concentrations in the water supply.

Furthermore, stagnant water can increase the risk for growth and spread of Legionella and other harmful bacteria. In August, five schools in Ohio and four schools in Pennsylvania detected Legionella in their water supply, which may have been due to the prolonged shutdown. The EPA’s Maintaining or Restoring Water Quality in Buildings with Low or No Use outlines strategies to help preserve water quality and prevent water stagnation during periods of low-to-no water use.

Contaminants of Emerging Concern (CECs)

While the SDWA covers a variety of chemicals that are known to harm human health, it does not cover all water pollutants that could pose risks to our health. Scientific knowledge about different types of water pollutants and safe exposure levels is constantly evolving, and it’s challenging for regulations to keep pace with the evolution of scientific knowledge.

Generally, the contaminants that we already regulate have been studied for a longer period of time and thus we have more established bodies of evidence specifying what amounts of those chemicals can be harmful to us. But there are also potential concerns related to the many contaminants that we are still learning about and don’t currently regulate on the federal level. In fact, the EPA keeps a list of “candidate” pollutants for SDWA regulation.

Unfortunately, establishing definitive relationships between specific amounts of these contaminants in our drinking water and health effects is very challenging for a number of reasons. For example, contaminants are often present only at very low concentrations, or appear mixed up with other contaminants, or are present over such long periods of time that their effects are difficult to distinguish. These factors make it difficult for scientists to determine with adequate certainty whether a specific contaminant may have caused health effects, but this doesn’t mean that the relationship between a contaminant and a health outcome doesn’t exist.

Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)

An example of a CEC is PFAS, which can be found in industrial and consumer products, such as stain repellents and non-stick cookware coating, and are widespread in our drinking water. In fact, a 2016 study found PFAS in the drinking water of more than 16 million American homes across 33 states.

Research suggests that exposure to high levels of certain PFAS may lead to adverse health outcomes such as decreased vaccine responses in children, higher cholesterol levels, and increased risk of kidney or testicular cancers. In 2016, the EPA established a non-enforceable lifetime health advisory for exposure to two types of PFAS, but on the federal level there are currently no enforceable standards or requirements for water systems to test for or treat PFAS — although some states are taking action. There has been significant legislative activity in regards to PFAS-related issues and several bills are currently pending review. The National Sanitation Foundation (NSF) has also established a voluntary standard to verify the ability of water treatment devices to reduce PFOA/PFOS below EPA health advisory level.

Pharmaceuticals and Personal Care Products (PPCPs)

Another example of CECs is pharmaceuticals and personal care products (PPCPs). This diverse group includes human and veterinary drugs, caffeine, sunscreens, cosmetics, insect repellants, shampoos, fragrances, skincare products, and more. PPCPs are able to persist during wastewater treatment processes and can then be discharged into surface water or groundwater, from which they can enter our drinking water supply.

They have been linked to adverse effects in humans — for example, some PPCPs can act as endocrine disruptors, interfering with hormonal function. There is currently little monitoring or data on their prevalence in drinking water, let alone regulation, although some PPCPs are on the EPA’s most recent list of candidate pollutants for regulation.

What Can We Do To Ensure Safe Drinking Water?

Ensuring that the water we use and consume is safe and clean involves reducing the levels of contaminants at both point-of-entry (POE; meant to treat all the water that comes into the building) and point-of-use (POU; meant to treat water that comes out from a specific location, like a tap).

Types of Water Treatment Methods

In general, different types of water filters or treatment methods reduce different contaminants. For example, some can make your water taste better while others can filter out harmful chemicals or germs. While filtration is one of the most effective treatment methods for mitigating water quality concerns, no single type of filtration technology readily available on the market today can keep every type of contaminant out of your drinking water. Since each technology has its own advantages in removing specific contaminants, a combination of different filtration technologies can be used to reduce a wider range of pollutants in drinking water.

Below we list a few popular water filters and treatment methods and identify the specific contaminants they target:

  • Sediment filters: Reduces visible particulate matter, dirt, sand and dust.
  • Carbon filters: Improves the taste and odor of water and reduces chlorine, chloramine, disinfectant by-products, some pesticides and pharmaceuticals.
  • Reverse osmosis: Reduces suspended solids, microorganisms, dissolved contaminants, common chemical contaminants (metal ions, aqueous salts) including sodium, chloride, copper, chromium, and lead; arsenic, fluoride, radium, sulfate, calcium, magnesium, potassium, nitrate and phosphorous.
  • Ion exchange: Reduces the amount of hardness ions (calcium, iron, magnesium and manganese).

For a more comprehensive list, please refer to this table.

Common NSF Certifications

The NSF is the leading certification body ensuring that certified water treatment products and systems meet rigorous quality, reliability, performance, and health and safety standards. Below are a few common NSF certifications to take into consideration when selecting a water filter. For a full list of certifications, please refer to NSF Standards for Water Treatment Systems.

  • Filters with NSF 42 certification are certified to reduce excess chlorine , as well as improve taste and odor.
  • Filters with NSF 53 certification are certified to reduce contaminants with known health effects (such as lead, chromium, VOCs, etc.).
  • Filters with NSF 401 certification ensure that the water treatment system reduces up to 15 individual contaminants such as prescription drugs, over-the-counter medications like ibuprofen and naproxen, herbicides and pesticides, as well as other chemical compounds like Bisphenol A (BPA).
  • Filters with NSF P231 certification certify that the filters were tested and shown to reduce potentially pathogenic bacteria, viruses and live cysts.
How To Select a Home Water Filter

It is important to remember that the performance of a water filter highly depends on the quality of the filter and the specific claims made by the manufacturer and verified by the third-party testing organization for each filter. Below are some steps to help you determine which filters and/or water treatment methods may be right for you.

  1. Know your water source. If you get your water from a private well, the Centers for Disease Control and Prevention (CDC) recommends having your water tested by a state-certified lab at least once a year. If you get your water from a public water system, consult the annual Consumer Confidence Report (CCR) which reports contaminant levels and drinking-water quality from all public water systems. A water test kit can also be used to test the quality of your water and can be purchased online or at a water filter store.
  2. Determine key contaminants of concern. It is important to select a filter that will address your specific water quality concerns based on your water quality assessment. This NSF website can help you find a filter certified to remove the contaminants you are most concerned about. If your water quality was tested by a professional, consult with them for advice as to which filter might be best for you.
  3. Check the product label. Before purchasing a water filter look for an NSF seal, Water Quality Association Gold seal, or IAPMO R&T seal for added assurance that your filter will actually do what the manufacturer claims.

Clean Water Is Essential for a Healthy Home

You may already know that consuming polluted water can be harmful to your health, however, many of us fail to consider possible water quality issues in our own homes. While some water pollution effects are easy to recognize immediately, others may be more difficult to detect. Ensuring that the water we use and consume is safe and clean means reducing potential contaminants that might be present.
Everyone deserves the peace of mind that comes with access to clean drinking water. Contact us to see how our water quality solutions can help to protect the health and well-being of you, your loved ones, and anyone who steps foot through your door.


Contributors: Yue Xu, MS