I became highly conscious of what could be in the water I was drinking while pregnant and breastfeeding. I began to research the specific contaminants in the water in our home and which water filters could mitigate them, all the while growing increasingly alarmed by the state of the nation’s drinking water.
There is a sea of water filtering products on the market, and it can be hard to know where to start in the search for one. While my informal research continues to this day, I’d like to share an approach to selecting a water filter that has helped me, with the hope that it might be helpful to you in your own journey.
- Identify the Contaminants That Exist in Your Drinking Water
I use the EWG (Environmental Working Group) Tap Water Database to see what contaminants are above the recommended threshold in the water supply in my town. You can search for your own town by entering your zip code and selecting your water provider, if there are several listed.
As an example, I learned that my drinking water has 10 contaminants at levels above the recommended thresholds (see image).
The levels of Chromium (hexavalent), PFOAs, and radium concern me. For the other contaminants at high levels in our water, such as trihalomethane and haloacetic acid (disinfection byproducts), it has been easy to find filters to address them. It has been more of a challenge to find the right filter for the aforementioned three contaminants, taking into account the preferences and constraints of my household – factors that I touch on in this blog as part of the overall process for selecting a water filter.
As a first step, I homed in on the three contaminants of concern:
Polyfluoralkyl Substances, or PFAs
PFAS are per- and polyfluoroalkyl substances, synthetic chemicals that can be found in waterproof products, nonstick pans, and fire extinguishing foam, to name a few, and they are contaminating our food, water, household dust, and soil. The list of health effects is long and concerning.
Our town just started tracking PFOA levels (one type of PFA) and the EPA is finally starting to recognize the levels of PFAs in the water across the US as a serious issue. There is currently no legal limit for levels in water and no level safe to ingest. PFAs are becoming a hot topic – I see water filter companies increasingly advertising their product’s abilities to remove them – but it doesn’t appear that all U.S. towns are measuring the presence of PFAs in their water supplies yet.
Radium
Radium, a radioactive substance, can be present naturally in groundwater or produced as a result of oil and gas extraction. According to the EWG, about 45% of the US population has tap water with radium levels above the legal limit – a limit that does not mean one is protected against developing cancer due to radium. Recognizing this issue, California has set a lower limit than that at the federal level.
Chromium-6
The carcinogen Chromium (hexavalent) can occur naturally but is also produced by industry (think Erin Brokovitch). There are no federal limits for chromium-6 currently (only for total chromium, which includes chromium-3), and California again has led the way by setting one, though some say this level should be lower.
I didn’t see Chromium-6 listed in our town’s water quality report published last year, so I called our water supply department and learned something interesting. The city tested for Chromium-6 a few years back as part of an ask from the EPA, but then the EPA discontinued making it a requirement, and testing for it was ceased. From what I’ve read on the online, the EPA was monitoring chromium-6 levels in locations across the U.S. between 2010 and 2015 and studies were being undertaken to better understand the harm to humans. I haven’t yet found information about the federal government’s plans for setting a limit.
These are just the contaminants that I have identified in our town’s drinking water as problematic. When searching other zip codes across the country, I saw alarmingly high levels of contaminants in many locations. Some examples:
- Norman, OK has 1,967x the EWG-recommended level of chromium-6.
- A zip code in Burnet County, CO has 1,150x the legal limit of arsenic.
- Hoosick Falls, NY has 5,166,153x the EWG-recommended levels of PFOAs.
It is definitely worth looking at the EWG website to see what the levels are in your drinking water. Note that the EWG reports may include some contaminants that don’t show up in the current town quality report, so be sure to look at both the EWG database and your town’s water report. (Here in Massachusetts, EWG uses data from the MA Department of Environmental Protection and the U.S. EPA Enforcement and Compliance History database. EWG also sometimes conducts their own testing, such as they did recently for PFAs.)
Lastly, keep in mind that pipes within and leading to your home could introduce other contaminants into your drinking water, such as lead and copper. You likely can get your water tested through your town’s water department, which is what I did to learn that levels of lead and copper in our tap water were not of concern.
2. Consider Your Preferences Around the Filtering Technology and Product Types
As a next step, it may be helpful to understand the main types of filtering technologies found on the market and what types of contaminants each tend to remove effectively. Many filtering products combine use of two or more of these technologies for effective filtering.
- Carbon and activated carbon: Carbon blocks and activated carbon can remove many contaminants, including some heavy metals like lead and mercury, disinfection byproducts like total trihalomethanes, industrial pollutants like benzene and toluene, pesticides, BPA, and some pharmaceuticals. Carbon filters use adsorption, which means it attracts the contaminant molecules, which then adhere to the carbon. But there are many concerning pollutants that it cannot remove, such as arsenic, hexavalent chromium, nitrate, radium, and perchlorate/PFAs. Carbon filtration is used in many types of filtering products on the market, whether countertop, faucet-based, under-sink, or whole house.
- Ion exchange: This technology uses a physical-chemical process to swap out select contaminants (ions) with ions of similar electric charges. It can be used to soften hard water, as well as to remove contaminants like nitrate, arsenic, chromium-6, PFAs, and radionuclides, like radium and uranium. Note that there are several types of ion exchange, and the one used will depend on what you are trying to remove. Many filter products combine ion exchange technology with other filtering technologies, like carbon.
- Reverse osmosis: Reverse osmosis (RO) is a physical method that uses pressure to pass water through a semi-permeable membrane, removing all contaminant ions or particles larger than water molecules. As a result, RO tends to be the most effective at removing a comprehensive range of contaminants. The multiple stages of filtration in RO can include use of carbon and sometimes also ion exchange. However, the downsides are that RO can be a big commitment in terms of cost and installation effort and the process tends to waste a lot of water.
Note that some of these technologies, such as reverse osmosis and the combination of ion exchange and carbon sometimes can filter out most dissolved solids, including healthy minerals that are important for our fundamental bodily functions. This also can result in poor tasting water, because with so many minerals removed, the water is left with an acidic ph. The healthy minerals can be added back in through different mechanisms. However, based on a WHO report from 2003 that investigated the risks of healthy minerals being stripped out of drinking water, it’s not clear that adding them back in gets you the same benefit and, in fact, could potentially pose some risk. Many RO systems will include a remineralization stage to add back in healthy minerals, but it’s unclear as to whether it achieves the same benefit as the healthy minerals that occur naturally in water.
For the contaminants in my family’s water supply, a reverse osmosis product or a filter using carbon and ion exchange would be the best solution. But there are other factors to consider, including investment, installation effort, and whether you want to retain healthy minerals. These can vary quite a bit, so it may help to understand the four main filter product types:
Because my learning about water filters is ever-evolving, my family has not wanted to commit to an under-sink unit just yet, knowing that we could discover new information that causes us to transition to a different product. For instance, I was about to pull the trigger on an under-sink reverse osmosis product, but then learned about the potential issues with removing healthy minerals and the question as to whether remineralization would be effective. So we have mainly gone with products involving less commitment, largely countertop and faucet-based units. I describe what I’ve learned about specific filters we’ve tried in the last section of this post.
3. Select a Water Filter That Is Certified to Remove the Contaminants of Concern
There are an overwhelming number of water filter options out there. As a way to narrow the field of options down in a smart way, it’s best to go with certified filters, as you wouldn’t know otherwise if a product reliably removes the contaminants that it claims to remove. The certification bodies are:
It takes some effort to get to the bottom of what product is truly certified and specifically for what and how well. Here are three things you can do to figure this out:
- Check a list of approved products on the California Water Boards website: California has more stringent standards for products (think of the California Proposition 65 warnings on so many products). For water filters, the CA Water Boards makes available lists of approved products for sale in California, including lists organized by specific contaminants of concern, including chromium-6, arsenic, lead, and nitrate. You could use these lists as a starting point to narrow down your options and identify candidate filters to buy, and then evaluate which one best meets your preferences in terms of contaminants removed and product type (countertop vs under sink vs faucet-based). Or, if you have already identified a product of interest, you could check these lists to determine if it is an approved product in California.
- Find the performance sheet for the product you are interested in, on the company website, to see what contaminants the company claims the product removes. The sheet should also state whether it is certified, and by whom. Sometimes it isn’t clear, though, or is misleading – for example, one product that I saw stated that the third party lab that tested its products is IAPMO certified lab, without explicitly stating that its product is IAPMO certified. So I reached out to IAPMO to find out if it is certified, and it turns out they are not.
- Go to the certification company’s website (if you’ve been able to identify it) and search for the particular brand or product of interest to confirm that it is actually certified. If it shows up, you can usually drill into the specific standards for which they are certified and the specific contaminants. For example, go to the NSF website and search for the name of the product you are considering to see if it has been certified by them and for which specific contaminants.
I’ll use AquaTru Countertop as a an example. You can find their performance sheet on their website. You can see on that sheet that they are certified by IAMPO, so you can then go over to the IAMPO website Product Listing and search for AquaTru, using “Listee” as the search category. Once you get the results, you can click into each line item to see details on the certification for this company, including the specific products certified and the specific contaminants they are certified to remove. I did this and saw that both sources of information were aligned. (I also contacted IAMPO to make sure I was accessing the information correctly, and they sent additional information listing the VOCs that the AquaTru product removed.)
What We Use in Our Home
We’ve been through a lot of filters! It’s been hard to find a filter that meets all of my requirements. They are:
- Certified by a legitimate certification body: This gives me some peace of mind that it’s been tested by a legitimate testing body and has shown to remove the contaminants it claims to remove.
- Registered to be sold in California, which has stringent product safety requirements.
- Countertop unit: My husband is not a fan of installing an under-sink reverse osmosis (RO) filter mainly because I’ve been known to rotate between filters quite often, and under-sink installation is a commitment – you need to have someone come in and install it and also make a hole in our sink for a dedicated faucet (which usually comes with the filter).
- Removes a large number of contaminants of concern without stripping the water of every last mineral, including the good ones (see here for more details)
Note that if the countertop unit requirement were removed, we’d probably have an easier time finding an ideal RO (the Aquasana OptimH2O® Reverse Osmosis + Claryum® Under-sink filter, as described below).
Currently, we are using the Aquasana Clean Water Machine. It mostly fits the bill for what I was seeking:
- It is NSF-certified and registered to be sold in California
- It is a countertop unit
- It is able to remove a wide range of contaminants, including PFOAs/PFOS, without removing healthy minerals
- However, the two contaminants of primary concern in Cambridge water that it doesn’t remove are chromium-6 and radium.
Insights on Filters I’ve Tried
Not Bad, But Leaves Something to Be Desired
Before this unit, we used a series of other filters, most of which were not certified, which always made me feel a little uncomfortable. Here is a rundown of the filters I tried and can comment on firsthand:
- AquaGear: We used their water pitcher. I was initially drawn to their product because they claimed to remove a wide range of known offensive chemicals, including Chromium-6. Initially I thought it was certified, but after digging deeper, I learned that they are in fact not certified. I emailed Aqua Gear to ask about why they wouldn’t get certified and couldn’t get a clear answer. Not only that, but earlier this year I received an email from them saying they were changing their filters so that they no longer will be filtering out Chromium-6 (or fluoride), and instead will be focusing on PFOAs, but I was extremely disappointed a) that they misled consumers on their website in saying they were already doing that, and b) that they’ve decided to no longer filter out Chromium-6. On top of feeling uncertain about its effectiveness and not trusting the company anymore, I don’t love that it’s a plastic pitcher. Oh, and the ink at the top of the container dissolved off and into the water over time. Wonderful.
- Zero Water: It is NSF certified for chromium, lead, mercury, PFOA, PFOS, and chlorine, but the water tasted bad because the filter strips out all total dissolved solids, including the healthy minerals. Also, nearly all of their pitchers are plastic, though they do offer one product that is a large glass container.
- Clearly Filtered: I like their claims of taking out a quite comprehensive range of chemicals, but it isn’t certified either. They say they have had their product tested by a certified lab, but that isn’t the same thing.
- Pur water faucet filter: We have this on our sink and used it as our primary filter for a time. It is NSF-certified for a good number of chemicals, though it doesn’t filter out PFAs, chromium or radium.
Insights on Other Filters I Researched
- Aquasana OptimH2O® Reverse Osmosis + Claryum® Under-sink filter: If we ever decide to do reverse osmosis under sink, this would be my first choice. It is one of the most comprehensively certified products on the market – including the ability to remove Chromium-6, among many other noxious chemicals. The final filtration stage includes remineralization to add back in the healthy minerals, though I’m still unclear about whether or not this achieves the same benefit as being tnaturally found in the water.
- AquaTru Countertop filter: This countertop filter also removes most of the nasty chemicals we know about, including Chromium-6, and is certified by IAMPO. I called the manufacturer to make sure I was reading their records correctly and they do support the claims made by AquaTru, which is good. And it doesn’t need to be installed under our sink. The downsides are that it is another plastic container, and, while it removes everything, it also removes the good minerals that you want to have in your water, such as calcium and magnesium, which may not be a good idea.
- Berkey filters: Although the Berkey filter sounds great, it is not certified, and they seem cagey about their testing results. A Wirecutter review of their products revealed that their own testing of what their filters removed were inconsistent, so I stay away from their products. I know a lot of people who anecdotally love Berkey filters, though, and the range of contaminants they claim to remove on their website sounds pretty good! If they got certified, I’d probably buy one.
Conclusion
The right filter for one family may not be the right one for another. The dependencies are mainly on what chemicals are problematic in your tap water, which chemicals are most important for you to remove, and what your preferences are in terms of usage and installation (under sink, countertop, plastics used, etc,). This post hopefully provides a high level approach to identifying the best filter for your needs.
Photo by Ekaterina on Creative Market