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Is Your Tap Water Safe to Drink? Here’s How to Find Out — and What To Do About It

The Bioregulatory Medicine Institute

tap water being poured into a glass

A few years ago, I relocated to rural New Hampshire with high expectations of having amazing drinking water. The area I now call home boasts pristine surroundings characterized by minimal industrial history, as the land was primarily used for farming and logging. The landscape is breathtaking, featuring dense forests, imposing mountains, meandering streams, and picturesque lakes. Why wouldn’t the drinking water, which is sourced from five aquifers, be wonderful?

The Environmental Working Group’s (EWG) Tap Water Database

To my disappointment, the water supply, sourced from a small private community utility which serves 3,000 residents, doesn't taste particularly good. After entering my zip code on the Environmental Working Group (EWG) website, I discovered that my tap water contains a whopping 12 contaminants, with 9 of them exceeding the EWG’s recommended levels (which are stricter than the legal limits, but not necessarily safe). Seven out of the nine contaminants were from disinfection byproducts — some of which are “contaminant groups” of harmful substances. Surprising, right?

Confused by such startling contaminants, I compared it to my previous utility (in RI, serving 51,000 residents), which reported 26 total contaminants with also 9 exceeding the EWG recommendations. So, NH was sort of an improvement, but not really.

We promptly purchased a popular countertop water filter device for drinking and cooking and just accepted this as the norm. However, I couldn't help but wonder whether this step alone provides sufficient protection. I’d like to share with you what I’ve learned since then. The answer’s a little complicated; first, you’ll need a little background…

Sub-Par Water

Eighty-six percent of the U.S. population is like me and relies on a utility to provide, test, and maintain the water supply (the other fourteen percent use private wells). But why, in this day and age, is the drinking water so sub-par?

Outdated Regulations Are Mostly to Blame for Why Our Tap Water Isn't Safe

The answer to that lies with the Environmental Protection Agency (EPA), which has not done enough to update stricter safety limits, enforce regulations, and support communities to ensure healthy water for all of us. In fact, half of all contaminants found in tap water surprisingly do not have a regulatory limit. “Forever chemicals” (PFAS) are not currently regulated in the U.S. drinking water supplies, and it’s been at least 20 years since legal limits have been updated.

Perhaps you could say that the EPA made an effort when it enacted the federal Safe Drinking Water Act, or SDWA, in 1974. This act established EPA standards for some contaminants, such as arsenic, copper and lead, but that was quite a few years ago, as it hasn’t been updated since 1996. Safety limits for PFAS (the forever chemicals), hexavalent chromium, and more than 160 other unregulated contaminants that taint our tap water haven’t been updated in over 50 years.

Thankfully, as I mentioned earlier, the EWG is truly working to improve everyone’s drinking water. Their website shows you what’s in your drinking water and what you can do about it.

The Environmental Working Group’s Standards

The EWG has established health-protective standards for drinking water contaminants where the EPA has not. The majority of the EWG’s guidelines have been established by scientists in the California Office of Environmental Health Hazard Assessment, who constantly examine and update water quality standards. According to the EWG, “A California public health goal is [to establish limits for] ‘the level of a chemical contaminant in drinking water [so that it] does not pose a significant risk to health’ when consumed for a lifetime.”

The EWG also communicates cancer risk levels for drinking water contaminants in their guidelines. They source this information from the EPA Integrated Risk Information System (IRIS), which identifies credible health hazards associated with exposure to a chemical and evaluates the relationship between the amount of exposure and the probability of an adverse health effect.

There are still limitations to EWG’s guidelines. however, since it takes time to see the lifelong impacts of disinfectants and their byproducts on the human body.

The Problem with Treating Water with Chlorine

Disinfection byproducts are a common problem. Water treatment facilities often add chlorine (or other disinfectants) to the water to control microbial pathogens, but unfortunately, chlorine interacts with the organic matter naturally present in tap water and forms a class of halogenated chemicals known as “disinfection byproducts.” There are currently around 600 identified disinfection byproducts and perhaps another 600 unidentified ones. All of these disinfection byproducts, identified or not, are considered “emerging contaminants.” Some of these byproducts have little to no toxicity, while others have been associated with cancer and reproductive and developmental issues, at least in laboratory animals. Please note that “emerging contaminants” also refers to pharmaceuticals, detergents, and other newly discovered human toxins.

Here’s How to Clean up Your Tap Water

Here is the link to get started: Follow these steps:

1.) Enter your zip code, choose your utility, and scroll down to see what contaminants are in your water. Look at the information about the potential effect of the contaminant, how much it exceeds EWG’s guidelines, and whether there is a legal limit. This database is extensive, but some utilities are not included. If that’s the case for you, you can contact the utility for more information.

2.) Click on the “details” button to learn more about the contaminants in your tap water and what type of filter is best for removing your specific contaminants.

3.) Consider reading EWG’s “WATER FILTER GUIDE” to learn about the different types of filters, such as activated carbon, reverse osmosis, and ion exchange.

4.) Try to choose a filter that has third-party certification. This means that the filter system has been tested by an unbiased organization such as the Water Quality Association (WQA) or National Sanitation Foundation (NSF). Also, consider reading about the different filtration standards used by the NSF (see the next section). Choose a NSF certification (or another third-party certification company) that matches the standard you wish to address. (As a forewarning, there are many, many filters out there!) Note that some products will say that they are certified TO NSF standards; it is best to instead purchase products that are listed as NSF-certified, as this ensures that they truly meet or exceed NSF standards. However, not all companies choose to pay for third party certification since it is expensive, so if you are considering purchasing a filter without this seal, be sure to look carefully at their performance data sheet first.

Some of the Most Common NSF’s Certification Standards

Here are the standards used by the NSF when certifying drinking water systems. Use this to find the correct filter for your needs. For example, for filtering out disinfection byproducts from chlorine, NSF/ANSI 42, 53, & 401 certification would be the most appropriate, and you should look for a filter with this standard.

  • NSF/ANSI 42 Filters are certified to reduce aesthetic impurities such as chlorine and taste/odor. These can be point-of-use (under the sink, water pitcher, etc.) or point-of-entry (whole house) treatment systems.

  • NSF/ANSI 53 Filters are certified to reduce a contaminant with a health effect. Health effects are set in this standard as regulated by the U.S. Environmental Protection Agency (EPA) and Health Canada. Both standards 42 and 53 cover adsorption/filtration which is a process that occurs when liquid, gas or dissolved/suspended matter adheres to the surface of, or in the pores of, an adsorbent media. Carbon filters are an example of this type of product.

  • NSF/ANSI 44 Water softeners use a cation exchange resin that is regenerated with sodium or potassium chloride. The softener reduces hardness caused by calcium and magnesium ions and replaces them with sodium or potassium ions.

  • NSF/ANSI 55 Ultraviolet treatment systems use ultraviolet light to inactivate or kill bacteria, viruses and cysts in contaminated water (Class A systems) or to reduce the amount of non-disease causing bacteria in disinfected drinking water (Class B).

  • NSF/ANSI 58 Reverse osmosis systems incorporate a process that uses reverse pressure to force water through a semi-permeable membrane. Most reverse osmosis systems incorporate one or more additional filters on either side of the membrane. These systems reduce contaminants that are regulated by Health Canada and EPA.

  • NSF/ANSI 62 Distillation systems heat water to the boiling point, and then collect the water vapor as it condenses, leaving behind contaminants such as heavy metals. Some contaminants that convert readily into gases, such as volatile organic chemicals, can carry over with the water vapor.

  • NSF/ANSI 177 Shower filters attach directly to the pipe just in front of the homeowner’s showerhead and are certified to only reduce free available chlorine.

  • NSF/ANSI 244 The filters covered by this standard are intended for use only on public water supplies that have been treated or that are determined to be microbiologically safe. These filters are only intended for protection against intermittent microbiological contamination of otherwise safe drinking water. For example, prior to the issuance of a boil water advisory, you can be assured that your filtration system is protecting you from intermittent microbiological contamination. The standard also includes material safety and structural integrity, similar to other NSF/ANSI drinking water treatment unit standards. Manufacturers can claim bacteria, viruses and cysts reduction for their filtration system.

  • NSF/ANSI 401 Treatment systems for emerging contaminants include both point-of-use and point-of-entry systems that have been verified to reduce one or more of 15 emerging contaminants from drinking water. These emerging contaminants can be pharmaceuticals or chemicals not yet regulated by the EPA or HealthCanada.

  • NSF P231 Microbiological water purifiers are certified for health and sanitation based on the recommendations of the EPA’s Task Force Report, Guide Standard and Protocol for Testing Microbiological Water Purifiers (1987) (Annex B).

A Solution for Now

My current “popular pitcher-style water filter” might not effectively reduce the disinfection byproducts from my water because it’s certified by the WQA only for NSF/ANSI standards 42 and 53, and the performance data sheet is very limited. To address the specific contaminants in my household’s water and the volume we use, We will be best off with a filter that addresses NSF/ANSI standards 42, 53, 401 for now. I was able to find a replacement filter for our refrigerator, the UltraClarity Pro Water Filter Cartridge, which is indeed certified for NSF/ANSI standards 42, 53, 401.

Choosing the right filter can be challenging—but even a small upgrade in your water filter is a step in the right direction.


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