How to find out what’s in your water and find the best water filter for your situation.
How to find out what’s in your water and find the best water filter for your situation.
Find a full transcript here.
Other Nutrition Diva episodes mentioned in this episode:
Dirty Dozen - Much Ado About Nothing?
Research mentioned in this episode:
Welcome to the Nutrition Diva podcast, where we take a closer look at nutrition news, research, and trends so that you can make more informed decisions about what you eat. I’m your host, Monica Reinagel, and today’s episode was suggested by Chuck, who wrote:
“I really enjoyed your recent bonus episode on the Environmental Working Group’s ‘Dirty Dozen’ list—it helped me put those ratings in proper perspective. I was also wondering about their ratings on local water quality. How concerned I should be when drinking unfiltered local tap water that has been flagged by EWG?”
In case you’re not familiar with the Dirty Dozen list that Chuck is referencing, this is an annual list put out by the Environmental Working Group of the 12 fruits and vegetables with the highest pesticide residues. Although it gets a lot of media attention every year, it is somewhat misleading, for reasons I explored in the bonus episode that Chuck mentioned.
The EWG’s tap water ratings are not quite as well known as their pesticide rankings but might understandably raise alarms for those whose local water system has been flagged as hazardous. So, today I want to take a closer look at tap water safety in general, as well as EWGs methodology.
Let’s start with the basics: most U.S. tap water is quite safe. Under the Safe Drinking Water Act, the Environmental Protection Agency sets enforceable limits—called Maximum Contaminant Levels, or MCLs—for more than 90 chemicals, from lead to nitrates to disinfection by-products. Every community water system must test its water regularly in certified labs and publish an annual Consumer Confidence Report (CCR) showing how it did. You can usually find your CCR online via the EPA’s CCR Finder by address or ZIP code. And you don’t always need to wait for your annual CCR to get data: many utilities now offer real-time or quarterly dashboards
However, there are still some gaps in this system, which has had to evolve as new hazards are identified. The EPA recently finalized rules for PFAS (“forever chemicals”) but public water supplies have until 2029 to achieve compliance. We don’t yet have standards for microplastics or other more recently surfaced concerns, such as pharmaceutical residues and wildfire by-products.
And, obviously, the enforcement of public health regulations depends not just on laws and rules but also on political will, agency resources, and public trust. And all three have taken some hits.
Starting in 2017, the first Trump administration began rolling back environmental regulations across multiple domains, including clean air, water, and climate. While the Safe Drinking Water Act itself was not repealed or amended, there was a marked decline in the EPA’s enforcement activity. Between 2017 and 2020, both the number of inspections and the penalties issued under federal environmental laws dropped sharply.
Programs aimed at improving water infrastructure—especially for small or rural systems—saw budget stagnation. Meanwhile, state-level enforcement, which plays a big role in carrying out EPA rules, became patchier as many state agencies faced their own resource constraints.
This year (2025), President Trump directed the EPA to roll back certain water-efficiency rules, focused mostly on things like water pressure. However, critics worry that it sends a broader signal that environmental oversight is again being deprioritized. At the same time, staff cuts and shifting priorities within the agency have made it harder to stay ahead of newer threats—like PFAS and microplastics.
All of this has contributed to an erosion of public trust. And understandably so. When we hear that government agencies are being asked to do more with less—or told to back off entirely—it’s hard not to wonder whether anyone is really minding the store. It also opens the door to bridge efforts (or at least monitor) some of those potential gaps by non-governmental organizations like the Environmental Working Group.
The Environmental Working Group’s Tap Water Database draws on publicly available water quality reports—mostly the same ones required by the EPA—but applies a very different set of standards to evaluate safety. Instead of comparing contaminant levels to the EPA’s Maximum Contaminant Levels, EWG compares them to its own internal “health-based guidelines,” which are often set much lower than federal limits.
According to the EWG, these guidelines are based on the most recent independent research and reflect levels at which no adverse health effects are expected, even over a lifetime of exposure. But the result is that many utilities show up in the database as having “exceeded health guidelines,” even when they are fully compliant with federal safety standards.
Critics of the EWG’s approach point out several key issues. First, their thresholds are not subject to public review or stakeholder input the way EPA standards are. Second, the database often lacks context—for example, whether a contaminant was detected just once or repeatedly, or whether it’s a common trace element found in nearly all systems at levels far below known risk thresholds. And finally, their system doesn’t account for how contaminants are treated before the water reaches the tap. That means even a trace detection at the source can trigger an “exceeds guidelines” warning, when the levels in the water that actually reaches the consumer may be undetectable. In fact, because their “health guidelines” are so much more stringent than the legal standards, virtually every water system in the country ends up flagged for something—whether or not the actual risk is meaningful.
In fact, the vast majority of municipal water systems continue to operate well within the legal limits for regulated contaminants. More than 90% of community systems report zero violations in a typical year. That said, there are still gaps—especially in smaller systems that may lack the tools or funding to detect, report, or address problems quickly. And those are the places where additional vigilance might make the biggest difference.
The presence of a flag in EWG’s database may serve as a prompt to dig a little deeper into the data. But it doesn’t necessarily mean your water is unsafe—it may simply mean the EWG has set a bar that’s far higher than current regulatory or scientific consensus.
But at this point, you may well be wondering whether a water filtration system makes sense, so let’s talk about when it might make sense to use a water filter—and what kind.
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For most people served by a municipal water supply, filtration isn’t strictly necessary from a safety standpoint. But there are still plenty of reasons someone might choose to filter their water—ranging from peace of mind to concerns about specific contaminants to, quite honestly, taste. Because even when water is safe to drink it may still carry a faint chemical or mineral flavor that’s not especially appealing. A slight chlorine smell from treatment, for example, or naturally occurring minerals like iron or sulfur, which can give water a rotten egg smell.
In those cases, a simple carbon-filter can do the trick. Whether in a refillable pitcher or faucet-mounted, these inexpensive filters are very effective at improving the taste and smell of tap water. Depending on the brand, they may also reduce certain volatile organic compounds, and/or various heavy metals.
If you are concerned about other specific contaminants, it may be worth investing in a more targeted system. For these, I recommend looking for NSF/ANSI certification. This is an independent testing and verification system that evaluates whether a filter actually does what it claims to do. NSF is the National Sanitation Foundation, and ANSI is the American National Standards Institute—together, they’ve established standards for different types of filtration technologies and the contaminants they’re designed to reduce.
When choosing a filtration system, look for one that is certified to remove the specific contaminants of concern in your water supply. You can usually find this information on the product packaging or on the NSF’s own website, which maintains a searchable database of certified products.
Reverse osmosis systems are capable of removing nearly everything from your water—including beneficial minerals like calcium and magnesium. These minerals give water its characteristic clean, slightly sweet taste, which is why fully demineralized water can often seem flat or bland by comparison. But the absence of minerals can have health implications, as well.
The World Health Organization has raised concerns about the long-term consumption of demineralized water, especially in populations where dietary intake may be low. For that reason, the WHO recommends remineralization of RO-treated water in settings where it's the primary source of hydration—especially for infants, older adults, or those with poor overall nutrition.
And remember to keep up with recommended maintenance schedules. Filters only work if they’re changed regularly and old filter cartridges can actually degrade water quality or become a breeding ground for bacteria.
Finally, a quick note on bottled water. While many people assume it’s cleaner or safer than tap, the reality is more complicated. Bottled water is regulated by the FDA, not the EPA, and testing is generally less frequent. It’s also not subject to the same public reporting requirements. And recent studies have found that bottled water often contains significantly higher levels of microplastics—hundreds of thousands of particles per liter in some cases—compared to tap.
So if you’re drinking bottled water to avoid contaminants, you may be trading one type of concern for another. And in many cases, you’re just paying a premium for filtered municipal water—sometimes from the exact same source that comes out of your tap.
So where does that leave us?
The vast majority of tap water in the U.S. is safe to drink, and most municipal systems meet or exceed federal standards. To find out what’s going on in your neck of the woods, I suggest starting with the EPA’s CCR database. You can also take a peek at the EWG’s Tap Water Database but keep in mind that their ratings often sound more alarming than the underlying data warrants.
If you do decide to filter, use the NSF/ANSI ratings to ensure that your filtration system is appropriate for your specific concerns.
If you have a question you’d like me to answer, you can email me at nutrition@quickanddirtytips.com. If you’d like to find out about having me speak at your next live or virtual event, you can learn more at wellnessworkshere.com
Nutrition Diva is a Quick and Dirty Tips podcast. Holly Hutchings is our Director of Podcasts. Steve Riekeberg is our audio engineer, Morgan Christianson heads up Podcast Operations & Advertising. Thanks also to Nat Hoopes for his support and most of all thanks to you for listening!