Water Filtration Systems

Water pouring into a small clear glass, blue background.
Photo by Pixabay

In Part 1 and Part 2 of my What’s In Your Water? articles, I explained the problem with contaminants in tap water. I’ve also published a list of Common Water Contaminants. In today’s article, I’ll explore different types of water filters. It isn’t as simple as just buying a water filter pitcher and calling it done; each type of filter, even within individual brands, only reduces or removes certain contaminants.

Remember, check the Environmental Working Group’s tap water database first to find out what’s in your water (link under Additional Resources below).

Water Filtration Types

These are the main types of home water filtration systems:

      • Activated carbon
      • Ion exchange
      • Reverse osmosis
      • Ultraviolet (UV) Technologies
      • Distillation

Most companies use a combination of those to reduce or remove specified contaminants.

Activated Carbon Filters

In general, these are the least expensive types of filters to buy. There are two main types: carbon block and granulated activated carbon. Carbon block is better in that it is more effective, but both types’ effectiveness depends on how quickly water flows through the filter.1 The filters on these do need to be changed according to the manufacturer’s recommendations as bacteria grows on carbon filters after a certain amount of time.

Activated carbon chemically bonds with contaminants as water flows through the filter, thereby removing it from the water we drink. However, their performance widely varies. Some remove chlorine and improve the taste of water, and others reduce – though not remove – contaminants, such as asbestos, lead, mercury, and volatile organic compounds (VOCs). “However, activated carbon does not remove common inorganic pollutants such as arsenic, fluoride, hexavalent chromium, nitrate and perchlorate,” which are very toxic and potentially carcinogenic.2

Ion Exchange

Ion exchange is often used to soften water by reducing calcium, magnesium, barium, and radium, which can build up in plumbing and fixtures. But other contaminants remain in the water. Also, water softeners replace calcium and magnesium with sodium, so people with certain health conditions and/or who want to maintain a low-sodium diet should avoid drinking it. It should not be used for watering plants or gardens, either.3

Reverse Osmosis

Reverse osmosis is the most effective at removing contaminants. These systems usually include one or more activated carbon and sediment filters, and reduce or remove large numbers of contaminants. The Environmental Working Group (EWG) outlined how it works: “The initial activated carbon treatment captures and removes chlorine, trihalomethanes and VOCs. Next, during the reverse osmosis filtration, tap water passes through a semipermeable membrane that blocks any particles larger than water molecules. As a result, reverse osmosis systems effectively remove many contaminants, such as arsenic, fluoride, hexavalent chromium, nitrates and perchlorate.” But these systems waste a lot of water, using five times more water than they make useable. The unused or rejected water is flushed down the drain.4

Another downside to reverse osmosis treatment is that it removes minerals that are essential for health, such as iron, calcium, and magnesium. Some manufacturers recommend the addition of mineral drops for remineralization.

Ultraviolet (UV) Technologies

Ultraviolet treatment is good for killing chlorine-resistant microorganisms, as it destroys 99% of viruses and bacteria in water without chemicals. However, UV is only able to eliminate microorganisms in water. It does not remove any other contaminants from water such as heavy metals, salts, chlorine, or man-made substances like petroleum products and pharmaceuticals. I have not reviewed any UV systems since they are limited in their treatment of water.


Old-fashioned distillation vaporizes water and then condenses the steam back into water. “The process removes minerals, many bacteria and viruses, and some chemicals that have a higher boiling point than water. But it does not remove chlorine, trihalomethanes or VOCs from water.”5 I have not reviewed any distillation systems since they are limited in their treatment of water.

Person holding out a glass of water.
Photo by engin akyurt on Unsplash

Water Filter Testing & Certification

The Environmental Working Group (EWG) advises that filters of the same type “can vary in their capacity to reduce the levels of specific contaminants. To ensure that a filter can significantly lower a particular contaminant, check that it has been certified to do so by an independent third-party certification company.” Though there may not be a third-party certification for every specific contaminant, the type of filter should still at least reduce the levels.6 

The Water Quality Association (WQA) offers certification regarding filters for specific contaminant removal. The NSF International also tests and certifies products. I’ve put a link to both of their sites under Additional Resources below, but I’m not convinced that those are the be-all and end-all. This is because the WQA and the NSF only follow the standards of the Environmental Protection Agency (EPA). While I strongly support the EPA, they are woefully behind in regulating chemicals, especially in regard to water contamination. Elizabeth Royte, author of Garbage Land and Bottlemania, quoted Brita’s research-and-development group manager at the time her book was published in 2008: “We can’t claim to take it out if we don’t test for it, and we don’t test for it if the EPA doesn’t have a standard.”7 

Some companies use different and perhaps more thorough testing methods. Those companies should provide details about their testing methods right on their website. You can also contact the company and ask questions. If they can’t or won’t answer your questions, then they are not a reputable company and you shouldn’t purchase anything from them.

Environmental Working Group’s water filter recommendations

The Environmental Working Group (EWG) provides a handy chart identifying the type of filter required for the removal of specific contaminants. You can find this by entering your zip code on EWG’s tap water database page, then selecting your water utility, and scrolling toward the bottom of the page. You will find a chart similar to this:

Screenshot of water filter options for the various contaminants detected in my water, from the Environmental Working Group.
Click on the chart to enlarge it.

Unfortunately, none of the types of filters above remove everything.

Water Filter Brands

There are different types of water filtration systems, including countertop water pitchers, under-sink filtration systems, and whole home filtration systems. I mainly focus on countertop water pitchers and a few under-sink filtration systems, as whole-home systems are costly, require commitment, and warrant an entirely separate article.

Let’s go through some of the specific brands of water filter systems. Please note: This is not a comprehensive list of all available water filtration systems, as there are just far too many types to review. These are the main ones I have encountered. I do not get paid or earn money as an affiliate for any product in this article.


Brita water filter pitcher, red and clear

First, let me acknowledge that I have used Brita water pitchers for almost 20 years. But I have lost trust in this company and some of the things I discovered about Brita were unsettling.

For example, I learned that Brita is owned by Clorox, a company whose vested interest is in some of the very chemicals that clean and disinfect our homes. Clorox is also used globally to disinfect water. But the chemicals in Clorox’s products contaminate our water systems with toxins that cause or contribute to many diseases. This company has a conflict of interest! They are seemingly making a profit from the pollution, though they are certainly not the only company engaging in such practices.

Brita’s Filters

Brita makes several types of filters that each filter different contaminants. They use activated carbon, ion-exchange beads, and other proprietary methods. The ion-exchange beads may be made of plastic resin, which is derived from oil. Brita filter systems do not treat bacteria or microbes. Unfortunately, none of their filters reduce or remove everything. And none remove hexavalent chromium or PFAS.

While I found Brita’s website somewhat confusing regarding their water filter systems, they do provide a breakdown of what each of their systems filters in the chart below.8 Following is an outline of the details of each filter type.

Chart showing different Brita filter systems and what they reduce or remove from water.
Click on the chart to enlarge it.

Brita’s Pitcher – Longlast Filters (also called Elite filters):

These use “proprietary active filtering agents” (meaning they are not required to share how they work) to reduce the contaminants lead, asbestos, mercury, cadmium, 2,4-Dichlorophenoxyacetic acid, atrazine, benzene, endrin, ethylbenzene, carbon tetrachloride, dichlorobenzene, simazine, and tetrachloroethylene.9

Brita’s Pitcher – Standard Filters:

These combine activated carbon granules and ion exchange. Activated carbon granules absorb some contaminants and reduce mercury, chlorine taste, and odor. These filters also use Ion Exchange Resin to capture copper, zinc, and cadmium. Since I have used the standard filters for so many years, I was surprised to learn that the standard filters do not remove lead. We had our water tested for lead a couple of years ago (and it was not detected), but how many people have access to lead testing?

Brita’s Pitcher – Stream filters:

These seem less common but they filter only the taste and odor of chlorine, some particulates, and tricholorobenzene.

Brita’s Bottle filters:

I was initially really excited about these because they are so convenient – the bottle and filter are all in one. But these reduce the least amount of contaminants, only the taste and odor of chlorine and some particulates. These just aren’t worth the money.

Brita’s Faucet filters:

These remove the most contaminants, as they use a carbon block and reduce lead, chlorine, asbestos, benzene, tricholorobenzene, particulates, and “select pharmaceuticals, pesticides/herbicides, TTHMs and atrazine.”10 Additionally, they remove alachlor, carbofuran, chlordane, carbon tetrachloride, 2,4-Dichlorophenoxyacetic acid, endrin, chlorobenzene, dichlorobenzene, ethylbenzene, lindane, methoxychlor, simazine, styrene, tetrachloroethylene, toluene, toxaphene, trichloroethylene, and a list of volatile organic compounds (VOCs).11


Blue and white PUR water pitcher pouring water.

PUR’s filter systems seem quite similar to Brita’s, as their regular filters reduce roughly the same contaminants. PUR filters use multiple layers of filtration and contain both a proprietary blend of activated carbon and ion exchange materials. Contaminants, such as pesticides and pharmaceuticals, are adsorbed by carbon; heavy metals, such as lead and mercury, are adsorbed by ion exchange materials. PUR claims that they were the first to obtain NSF certification for emerging contaminants, meaning chemicals suspected to cause health or environmental problems that are not yet or have only recently been regulated.12

Also like Brita, PUR’s faucet system reduces far more contaminants than their regular pitchers, especially in the categories of industrial pollutants, herbicides and pesticides, and pharmaceuticals. Here are the ingredients that their faucet filters remove, that their basic filter pitchers do not: chlorobenzene, carbon tetrachloride, DEET, o-dichlorobenzene, styrene, trichloroethylene, TCEP, TCPP, asbestos, volatile organic chemicals (VOCs), 2,4-D, alachlor, atrazine, carbofuran, chlordane, endrin, lindane, metolachlor, simazine, toxaphene, bisphenol A (BPA), and total trihalomethanes (TTHMs).13 

While PUR’s faucet filters reduce a lot of contaminants, note that they do not address contaminants such as hexavalent chromium or PFAS.


3M Under sink Drinking water filter

3M sells under-sink water filters and whole home water filtration systems. But this is another example of a company that I just don’t trust. They are selling us a product that removes contaminants they allowed to contaminate our water, essentially profiting from the pollution they helped create.

Further, 3M (in addition to DuPont) spent decades producing PFOA, PFAS, PFCs, etc., and improperly disposing of them. These carcinogenic chemicals are now in our soil and water supply across the United States. “3M makes water filters that reduce ‘chlorine taste and odor, trihalomethane (THM), lead, sediment, cysts, arsenic, barium, cadmium, chromium (hex), chromium (tri), copper, fluoride, radium, selenium, turbidity, total dissolved solids (TDS), mercury, asbestos, chloramine, MTBE and volatile organic compounds (VOCs).’ No PFCs are mentioned,” despite 3M being one of the major producers and polluters. 14 In fact, when I searched “3m pollution” on Google, I got more than 9 million results. Buyer beware.

Screenshot of a Google search for "3m pollution", and the number of results circled in red.

Invigorated Water

Invigorated Water pitcher, clear and whiteThis brand’s focus is alkaline water. Their filters remove some contaminants such as chlorine, fluoride, and heavy metals using a multi-stage filtration system. They have two Micro-Nets that catch potentially dangerous particles while allowing beneficial minerals through. Next, Zeolite – a variety of minerals that contain alkali and alkaline-earth metals – reduces fluoride, and removes heavy metals, such as mercury, lead, arsenic, zinc, and copper. Coconut shell-activated carbon removes pollutants and chemicals. Last, a ceramic ball and stone blend increases alkalinity.

Invigorated Water filter cross section diagram

However, their website claims that their filters “remove chemicals, toxins, chlorine, fluoride, heavy metals,” but it does not elaborate on specific chemicals and toxins. So I emailed the company to find out more information. Though they made me answer specific questions about my article before they would answer my questions, the company was very responsive. In the end, their filters remove heavy metals (aluminum, arsenic, cadmium, chromium-3, iron, lead, and selenium), and reduce chlorine, nitrate, fluoride, and sulfate. However, their filters do not remove chemicals or volatile organic compounds (VOCs), such as PFAS or hexavalent chromium.

Advocates of alkaline water claim that it improves health and provides better-tasting water. But when I researched alkaline water benefits, I discovered that these claims are controversial. Most of the major online medical websites indicate that there are few studies supporting alkaline water’s health benefits. If you’re interested in alkaline water benefits, I recommend further research.

Enviro Products Alkaline Water Pitcher

Image of Enviro Products Alkaline Water Pitcher packaging

This is also an alkaline home water system, one I discovered at Whole Foods. Their Alkaline pitcher, the one shown at left, filters chlorine only. The Alkaline Plus pitcher filters chlorine and removes lead. But their 10 Stage Plus Countertop Filter System uses multiple filtration types to filter out many contaminants, including a micron pad, activated carbon, and ion exchange. This system removes chlorine, total trihalomethanes, arsenic, heavy metals, pesticides, herbicides, and “many other organic pollutants.” I wanted to know what “other organic pollutants” include, so I emailed the company to ask. Unfortunately, they never responded to me.


Lifestraw home pitcher, white and clear, with water in it

Lifestraw’s purpose began with supporting underrepresented communities globally and fighting water-borne diseases. In 1999, they developed a plastic pipe filter to strain out Guinea worm larva and grew from there. Today, Lifestraw is a Climate Neutral Certified B Corp. They believe “everyone deserves equitable access to safe drinking water” and claim that “for every product sold, a child in need receives access to safe water for an entire year.”15

Today they offer different home systems based on the type of use, including home use, travel, outdoor, emergency, etc. Or, you can shop by water contaminant concern, such as bacteria, viruses, chemicals, lead, etc. This is really useful for someone aiming to solve a specific problem. Lifestraw seems transparent and publishes details on every product and what it specifically reduces or removes. If you are traveling globally, this seems like the type of product you’d need.

Lifestraw’s home pitcher is glass, which is quite different from most other home systems that use plastic. The filters use a combination of processes, including a membrane microfilter, activated carbon, and an ion-exchange filter. Together, this removes the majority of bacteria, parasites, and microplastics; and reduces heavy metals including lead, chlorine, herbicides, pesticides, some pharmaceuticals, and PFAS!

Lifestraw home pitcher data sheet
Click on the chart to enlarge it.

Unfortunately, for me, it does not reduce or remove hexavalent chromium (chromium-6).


Zero Water pitcher with tester on leftZeroWater uses a five-stage Ion Exchange filtration to remove 99.6% of detectable dissolved solids. They claim that their filters produce water that is a similar purity level to the water from a reverse osmosis system.16 They remove antimony, arsenic, barium, beryllium, cadmium, chromium-3, chromium-6 (hexavalent chromium), copper, iron, lead, manganese, mercury, selenium, silver, thallium, zinc, asbestos, chlorine, cyanide, fluoride, nitrate, nitrite, and PFAS.17 The main page of this company’s website claims to be the only filter NSF Certified filter to reduce PFAS. This seems like a good option.


Berkey Filter systems combine three types of water filtration. They use ion exchange, starting “with water going through the filter elements, which are made up of more than six different media types and billions of micropores (aka tiny holes). These holes are so small that harmful materials are unable to pass through. Next, the adsorption process keeps out harmful chemicals that are smaller than the pores. After that, harmful metals are attracted to the media using ion exchange. All of this is slowed using a gravity flow process,”18 which allows water to flow through the filter so slowly that contaminants aren’t able to get through. They do not use chemicals, such as iodine or chlorinating tablets, to purify the water. From their website: “We do not have to use chemicals in our unique ionic adsorption process mated with simple microfiltration. In short, these two methods create a pore structure so minute that contaminants are removed from the water because they simply cannot pass through the charged filtering media.”19 20 But water does retain important minerals that our bodies need.

Berkey filters remove the following (I’ve bolded the toxins in my water highlighted in What’s In Your Water? Part 1); bacteria; microorganisms (like e.Coli); viruses; trihalomethanes including chloroformchloramines; chlorine; chloride; haloacetic acids; heavy metals including lead; vanadiumchromium-6 (hexavalent chromium); manganese; and pharmaceuticals including acetaminophen; caffeine; carbamazepine; ciprofloxacin HCl; erythromycin USP; sulfamethoxazole; trimethoprim; BPA (bisphenol A); diclofenac sodium; 4-para-nonylphenol; 4-tert-octylphenol; primidone; progesterone; gemfibrozil; ibuprofen; naproxen sodium; triclosan.

They also remove (or reduce below detectable limits) so many pesticides (including glyphosate) and volatile organic compounds (VOCs) that I am unable to list them here (link in footnotes). They also remove or reduce arsenic; fluorine; nitrites; PCBs; phthalates; PFAS and PFCs; petroleum products; selenium; thallium; most radioactive substances including radium and strontium; rust; silt; and sediment.21 22 23

The only contaminants Berkey does not remove are nitrates and fluoride, though they offer an additional filter for the fluoride.24 The filters last a long time, through about 6,000 gallons of water, which is potentially several years of use. While Berkey advertises that the cost comes out to just 2 cents per gallon, the initial cost is high – in the $300-$400 range – and one of the most expensive set-ups in this review, but perhaps water free of toxins and carcinogens comes at a cost.

Charcoal sticks

Charcoal stick in a glass bottle with a cork top, sitting on a counter next to a small glass of water.
Photo by Callum Shaw on Unsplash.

Many zero wasters claim that charcoal sticks will purify drinking water, without the plastic waste that comes from all water filtration systems. Here’s how it works: “Binchotan charcoal is activated through extremely high burning temperatures, along with a rapid cooling process. Once the charcoal has been activated, the increased surface area can bind easily and is extremely porous, thus making it extremely useful at absorbing impurities and contaminants.”25 It can absorb metals found in tap water such as lead, mercury, copper, and aluminum.26

From what I can tell, charcoal sticks may remove most contaminants that activated carbon filters remove. But they will not help with volatile organic compounds, chemicals, or pharmaceuticals.

However, they are very affordable and extremely low waste. After 3-4 months of use in water, you can repurpose them. Use the sticks as an air freshener for your refrigerator, or crush them and put them in your garden soil. To ensure quality, I recommend using a well-known brand over an off-brand.


Bluevua countertop reverse osmosis water filtration machineThis company makes a multi-filter and reverse osmosis countertop system and an under sink reverse osmosis filtration system. The countertop model reminds me of a standard coffee maker. It has 4 stages of purification. The under sink version has 6 stages and requires installation, but the company provides instructions.

Reverse osmosis removes many contaminants! But remember, reverse osmosis typically wastes a lot of water. However, this company claims that its system only wastes water at a 1:1 ratio. They declare this to be 300% more efficient than comparable systems. The system also adds back in minerals that reverse osmosis typically removes. This product sounds great! The filtered water goes back into the fill tank.27 One thing that is not clear to me is what to do with the wastewater. The instructions indicate that the wastewater is contaminated and the company recommends “following the instruction of discarding [the] water,” only I did not see instructions on discarding the water either on the website or in the manual.

Note: There are quite a few companies making reverse osmosis systems. I researched just one for this article. AquaTru has been making reverse osmosis systems for a long time, but reviews imply that their systems have issues. Brita Pro has a whole home reverse osmosis system but appears to be only available through an authorized partner company. 

Image of hand holding a glass, getting water, under the kitchen faucet.
Photo by Andres Siimon on Unsplash.


I realize this is a lot of information, and it’s hard to know where to go from here. So let me reemphasize: first, find out what’s in your water, and what contaminants you are most concerned about. I’m most worried about hexavalent chromium (chromium-6), PFAS, VOCs, pharmaceuticals, and many others. It looks like my family will have to purchase a Berkey or ZeroWater system, but Berkey removes the most contaminants. However, it is quite expensive.

My goal is to stop using Brita, simply because it doesn’t filter out much. As soon as I purchase a new system, I’ll update this article and let you know which one we chose. I’ll also write a review on it! Please comment below on what you’re using to filter your water, as well as your experiences with water filtration! Thanks for reading, please share and subscribe!

Additional Resources:

Database, “EWG’s Tap Water Database,” Environmental Working Group.

Page, “Find WQA-Certified Water Treatment Products,” Water Quality Association.

Website, “Certified Products and Systems,” NSF International.

Page, “A Guide to Drinking Water Treatment Technologies for Household Use,” Centers for Disease Control and Prevention,” cdc.gov, reviewed August 4, 2020.


What’s In Your Water? Part 1

Photo of a person pouring water into a glass from a kitchen faucet, with a splash.
Photo by Jacek Dylag on Unsplash

There are many pitfalls when it comes to finding safe, chemical-free drinking water. Like a lot of people, when I was younger I drank my fair share of bottled water, thinking it was cleaner, healthier than soda, and readily available. I even reused the same plastic bottles over and over to try and minimize my use of plastic. In the mid-2000s I became aware of the dangers of chemicals leaching into water from single-use plastic bottles. So I immediately made the switch to tap water and never looked back.

For my home tap water, I’ve almost always used Brita water pitchers for drinking water. I thought I was filtering out whatever harmful chemicals and potential toxins that the water company didn’t filter out, hence making my water even safer to drink.

Only now am I finding out how wrong I was!

A Broken Brita pitcher

Brita filter pitcher with broken handle and orange top.
My broken Brita pitcher.

After beginning my journey toward plastic-free living, I had to address the plasticity of my Brita pitcher and its filters. At the time, I decided that using a home water filtration system was best since I didn’t want to buy bottled water, especially in plastic bottles. Also, I discovered that you can recycle Brita’s plastic filters, pitchers, and even the filter wrappers through a free TerraCycle program.1 I save all the waste and ship it off about once per year.

Our Brita water pitcher cracked at the handle about 3 years ago, probably because the company makes them out of cheap plastic (though Brita does not disclose what type of plastic is used in their pitchers, only that they are ‘BPA-Free’). We did not drop it or bang it on the sink or anything, we simply filled it and poured it. We kept using it because I refused to purchase another plastic pitcher, ‘recyclable’ or not. But now the handle has completely broken off.

Shopping Leads to Discoveries

On a recent shopping trip, I decided to replace my broken water pitcher. In the process, I discovered that there is more than one type of filter for Brita, and they offer different levels of filtration. It turns out that the different levels filter different contaminants. This immediately gave me pause. Was my family, drinking city-treated tap water while trying to avoid plastic, still exposed to toxins and chemicals in our water?

Additionally, there were many brands of water filtration systems, all offering promises of “cleaner” and “safer” drinking water. I soon felt overwhelmed and undereducated about water filtration, so I left the store without purchasing one. I planned to research water filtration systems, purchase one, and share my research with you.

But it’s much more complicated than I thought. And I discovered that our water situation is much worse than I ever knew.

Kitchen sink with faucet running.
Image by Karolina Grabowska from Pixabay

What’s In Your Water?

When I searched online for a comprehensive comparison of home water filtration systems, I kept seeing the same advice over and over again: Find out what’s in your water. Then select a water filtration system based on that. I found my way to the Environmental Working Group’s (EWG’s) Tap Water database, the most ambitious collection of data regarding tap water pollutants. “The database collects mandatory annual test reports from 2014 to 2019, produced by almost 50,000 water utilities in all 50 states and the District of Columbia.”2 The data is comprised of water quality analysis from more than 31 million state water records.

“For too many Americans, turning on their faucets for a glass of water is like pouring a cocktail of chemicals. Lead, arsenic, the “forever chemicals” known as PFAS and many other substances are often found in drinking water at potentially unsafe levels, particularly in low-income and underserved communities…[our database] reveals that when some Americans drink a glass of tap water, they’re also potentially getting a dose of industrial or agricultural contaminants linked to cancer, brain and nervous system damage, fertility problems, hormone disruption and other health harms.”-Environmental Working Group3

My Water

On EWG’s tap water database, I entered my zip code and found my water provider.4 What I discovered was so alarming that I almost cried!

Screenshot of the 7 contaminents found in my local water.

Above are just the contaminants that exceed EWG’s guidelines. My family’s tap water has 13 times the recommended limit on hexavalent chromium, a carcinogen made famous by the Erin Brockovich cases against PG&E since the 1990s. However, though I’d maybe heard of some of the other contaminants, I was not familiar with their toxicity or threats to human health.

“The [Environmental Protection Agency] standards were negotiated based on the technical feasibility and cost of water treatment and did not consider the long-term toxicity of these contaminants.” -Environmental Working Group5

Hexavalent Chromium

Chromium is an odorless, tasteless, metallic element that occurs naturally. Hexavalent chromium compounds are a group of chemicals with properties like corrosion resistance, durability, and hardness. These compounds have been used in the manufacture of pigments, metal finishing and chrome plating, stainless steel production, leather tanning, and wood preservatives. They have also been used in textile-dyeing processes, printing inks, drilling muds, fireworks, water treatment, and chemical synthesis.6 It may even be present at low levels in cement, which is used in concrete, mortar, stucco, and grouts.7

Also known as Chromium-VI, it was commonly used as a coolant and anti-corrosive at natural gas plants and electrical power stations. If not handled or discharged properly, it can seep into the groundwater and poison those who use the water, as was the case in the Erin Brockovich lawsuits. It can be ingested, inhaled, and absorbed through the skin.

It is a known carcinogen, causing stomach cancer, lung cancer, nasal and sinus cancers, kidney and liver damage, malignant tumors, nasal and skin irritation and ulceration, dermatitis, eye irritation and damage.8 It also causes all manner of reproduction problems to both males and females. Worse, it can cause developmental problems in fetuses. Other reported effects include mouth ulcers, diarrhea, abdominal pain, indigestion, vomiting, leukocytosis, presence of immature neutrophils, metabolic acidosis, acute tubular necrosis, kidney failure, and death.

“The EPA’s national survey of chromium-6 concentrations in drinking water revealed that the contaminant was found in more than three-fourths of water systems sampled, which supply water to more than two-thirds of the American population,” or approximately 232 million Americans.9

EPA has a drinking water standard of 100 parts per billion (ppb) for total chromium. This includes all forms of chromium, including trivalent (non-toxic) and hexavalent chromium.10 Based on a 2008 study by the National Toxicology Program, the California Office of Health Hazard Assessment set a public health goal in 2011 for chromium-6 in drinking water of 0.02 parts per billion. However, “the safety review of the chemical by the Environmental Protection Agency has been stalled by pressure from the industries responsible for chromium-6 contamination.”11 In other words, hexavalent chromium is allowed to be in our tap water in great quantities.

“It’s been common knowledge in the scientific community for years that people who inhale hexavalent chromium can contract lung cancer. Is it really so surprising that swallowing it also leads to cancer?” -Erin Brockovich12

Glass of drinking water
Image by Bruno Henrique from Pixabay

Total Trihalomethanes

Total trihalomethanes (TTHMs) refer to a group of harmful contaminants known collectively as disinfection byproducts. They are found in chemically treated water, which includes municipal tap water. These are formed when chlorine or other disinfectants used to treat drinking water react with plant and animal waste in drinking water supplies. But drinking water must be treated to prevent microbial diseases and pathogens. The Environmental Working Group (EWG) asserts that though necessary, “every measure must also be taken to decrease the amount of disinfection byproducts in finished drinking water served at the tap.”13

Four trihalomethanes include chloroform, bromoform, bromodichloromethane, and dibromochloromethane. The EPA’s legal limit for these in tap water is 80.0 ppb. But the healthy limit recommendation is 0.15 ppb, proposed by the California Office of Environmental Health Hazard Assessment (OEHHA) and adopted by EWG. Disinfection byproducts increase the risk of bladder cancer, pregnancy problems (including miscarriage), cardiovascular defects, neural tube defects, change to fetal development, and low birth weight. The EPA classified bromodichloromethane and bromoform as “likely to be carcinogenic to humans.”14 People are exposed to these by using water with these contaminants, whether it is drinking, eating food prepared with it, and bathing or swimming.

Bromodichloromethane is found in 48 states and is in the water of approximately 237 million Americans.15

“The federally regulated disinfection byproducts are just a small subset of a larger group of toxic contaminants that form during water disinfection. Hundreds of other disinfection byproducts form in drinking water and may harm human health.”- Environmental Working Group16

Close up image of a water/drinking fountain.
Image by Jason Gillman from Pixabay

Haloacetic Acids

This is another group of contaminants known as disinfection byproducts. The EPA’s legal limits for these are 60 ppb. But the healthy limit recommendation is 0.10 ppb, proposed by the California Office of Environmental Health Hazard Assessment (OEHHA) and adopted by EWG. In 2018, the National Toxicology Program classified six haloacetic acids as likely carcinogens.17 “Haloacetic acids are harmful during pregnancy and may increase the risk of cancer. Haloacetic acids are genotoxic, which means that they induce mutations and DNA damage.”18

Haloacetic acids are found in tap water in all 50 states and affect the water of approximately 260 million Americans.


Nitrate, one of the most common contaminants in drinking water, gets into water from fertilizer runoff, manure from animal feeding operations, and wastewater treatment plant discharge. “Tap water in agricultural areas frequently has the highest nitrate concentrations. Private drinking water wells in the vicinity of animal farms and intensively fertilized fields, or in locations where septic tanks are commonly used, can also have unsafe levels of nitrate,” even excessive levels.19

The legal limit of 10 mg/L (milligrams per liter, equivalent to parts per million), for nitrate, was set in 1992. “This standard was based on a 1962 U.S. Public Health Service recommendation to prevent acute cases of methemoglobinemia, known as blue baby syndrome, which can occur when an infant’s excessive ingestion of nitrate leads to oxygen deprivation in the blood.” The EWG recommended level of nitrate in drinking water is 0.14 mg/L, which is 70 times less than the federal limit.20 Nitrate is found in the water of 49 states and affects approximately 237 million people.21

Besides the effect on babies, nitrate is associated with thyroid disease, cancers, increased heart rate, nausea, headaches, and abdominal cramps.22 Worse, nitrate converts into other compounds in the digestive system, and they damage DNA and cause cancer in multiple species.23

“Nitrate pollution of U.S. drinking water may be responsible for up to 12,594 cases of cancer a year.”24


Radium is a radioactive element that can occur naturally in groundwater. But coal, oil, and gas extraction activities such as hydraulic fracturing (fracking) and mining can elevate concentrations in groundwater. Radium causes bone cancer; tumors in bone, lungs, and other organs; leukemia; and skin and blood damage. More than a dozen different radioactive elements are detected in U.S. tap water, including beryllium, radon, strontium, tritium, and uranium. But radium is the most common. These affect the water of approximately 165 million Americans. In addition to causing cancers, these may damage the nervous, immune, and endocrine systems. Worse,  radiation can harm fetal growth, cause birth defects, and damage brain development.25

Radium in water is measured in picocuries per liter (pCi/L), which is a measure of radioactivity in water. The current EPA legal limit, not updated since 1976, is 5 pCi/L but the EWG’s recommended limit is 0.05 pCi/L. It is found in the water systems of 49 states and affects approximately 148 million people.26

Other Contaminants in My Water

There were 6 other contaminants detected but under the recommended limits of the Environmental Working Group (EWG). These included chlorate, chloroform, total chromium, manganese, strontium, and vanadium.

Photo of a bird drinking water from a pipe with a green foliage background.
Image by 165106 from Pixabay

Now What?

I was most shocked because, in my area, the water utility we are on is considered one of the best around. It is in compliance with legally mandated federal health-based drinking water standards. So what happened?

As it turns out, almost everyone’s water is contaminated.

But how did the water in the United States get so tainted with chemicals and toxins? More importantly, what can I do about it? Can I filter these toxins out? In my next articles, I’ll explore the different water filtration systems and how our water became so contaminated and polluted. In the meantime, please investigate the contaminants in your own water at EWG’s Tap Water Database. I’ve also compiled a list of Common Water Contaminants. Thank you for reading, please share and subscribe!


Additional Resources:

Article, “Erin Brockovich: the real story of the town three decades later,” bABC News, June 10, 2021.

Article, “Drinking Water Nitrate and Human Health: An Updated Review,” by Ward, Mary H et al. International Journal of Environmental Research and Public Health, vol. 15, No.7, July 23, 2018