How to Know What’s In Your Drinking Water

TIM: A filter is not going to do anything bad to your water. So you’re not adding to your risk by using one. And if it’s important to you to just know basically that if there are any of the things that this filter is certified for in my water, they will then be gone then go ahead.

CHRISTINE: I’m Christine Cyr Clisset.

CAIRA: I’m Caira Blackwell.

ROSIE: I’m Rosie Guerin and you’re listening to The Wirecutter Show.

ROSIE: Hi friends.

CAIRA: Hi.

CHRISTINE: Hello.

ROSIE: Hello. Today we’re going to talk about water.

CHRISTINE: Water, the essence of life.

CAIRA: Sounds exciting.

ROSIE: Beautiful. I was in Philly last weekend visiting my father-in-law. We went out to dinner. The waiter came over and offered us tap water and he said something snarky like, “Tap is fine. It’s not as good as New York tap water, but Phillies will do.”

CAIRA: I mean, that’s true.

CHRISTINE: That is just like a Philly thing. They’re feeling inferior to New York.

CAIRA: What’s new?

ROSIE: No, it was funny. Because it came perfectly timed to us prepping an episode on water filtration. This is a thing that’s in the news. I mean, we continue to see news reports about microplastics, PFAS, Flint, Michigan, where the lead in the water crisis dragged on for about a decade. Similar issues with water in Newark, New Jersey near where I live. So these are things that come up and they’re big news stories. But I think people have questions about whether or not to filter their water regardless of where they live.

CHRISTINE: Yeah, I think that’s completely right. Water is one of those things you ingest the most during the day, and I think people rightfully wonder how is this impacting my health? How is it impacting the health of my kids? It feels like to me, at least, filtering my water is something that I feel I can actually control. We can’t control a lot of things in life and we’re ingesting water all the time. So for me, I know that I feel like if I filter my water, at least I’ve got a little bit more security, whether it’s a false sense of security or not. But a little bit more security that I’m keeping myself and my family a little bit safer. So I think in general there has just been a growing concern about whether people should be filtering their water at all.

CAIRA: But luckily, you don’t have to just keep wondering. You can actually find out. And we have somebody on staff who can help us cut through that noise. And it’s Tim Heffernan, he’s our senior staff writer who covers air and water filtration. He was actually on the show almost a year ago talking about air filtration, air purifiers. So we thought it would be a good time to have him back on again and talk about water filtration. And he’s just a wealth of knowledge. We love Tim. He’s been testing water filters and water test kits for Wirecutter for almost a decade now. It’s crazy.

CHRISTINE: We’re going to take a quick break and when we’re back we’ll talk with Tim about what you need to know about filtering your water.

CAIRA: Welcome back. With us now is Tim Heffernan, who is a senior staff writer on the home improvement team. He’s been writing for Wirecutter for over 10 years and has been covering water quality for just as long, basically. He was featured on our second episode ever on this podcast and he was chatting about air purifiers. And today, Tim, you’re going to talk to us about water filters.

TIM: I am, thanks for having me.

CHRISTINE: Welcome back, Tim. It’s great to have you.

TIM: Thank you.

ROSIE: Tim, I want to know off the bat, water filtration, water testing. How do you do the testing? What’s the setup like? Paint us a picture.

TIM: The setup is usually my kitchen basically. And I’m largely just going hands-on with the filters, living with them the way that our readers would if they use them, maybe running them a little bit more intensively. I don’t wait three months for the Brita filter to run through its life cycle. I’ll fill it 10 times a day for a week or so. But that’s it, I’m really doing kind of usability, maintenance, ergonomics testing, if you will, in terms of what the filters can actually do, what contaminants they’ll remove from the water. From the start, basically, we’ve relied on NSF/ANSI certification.

ROSIE: And explain what that is.

TIM: Yeah, NSF/ANSI is sort of the standard certification in the United States for a filter’s ability to remove contaminants. For a pitcher, for example, they will run between 120% and 200% of highly polluted water through the filter versus what it’s supposed to last for. And then measure if it meets the actual pollution reduction standard. So basically, they’re making sure that at the very end of the life of a filter, it’s still performing the way that it should be.

CHRISTINE: And you’re not just testing filters, you’re also testing water testing kits, right?

TIM: Yeah, I’ve done that quite a lot in the last few years.

CHRISTINE: Tell us what that is exactly.

TIM: If you’ve been to a hardware store, you’ve probably seen little off-the-shelf kits that you can get where you kind of dip a strip of paper and it changes color and you compare that to a little chart. We have tested those, but then there are a fair number of tests where you actually take a water sample and then send it away to a certified lab to have it tested and we’ve settled on those.

CHRISTINE: And what kinds of contaminants will that show you with a water test kit? What do you get back?

TIM: There’s various test kits. The basic ones tend to look for, I guess, what we would call historic contaminants. Lead is a no-brainer. That’s always going to be on there. Mercury, cadmium, pesticides, industrial compounds, and then you can typically add on other tests that might be specific to PFAS, forever chemicals, and other things.

ROSIE: Can I ask why the send-away test kits pulled ahead of the dip strips?

TIM: Yeah, the dip strips, especially the ones that test for more contaminants are extremely hard to read, basically. You only typically have, I don’t know, 30 seconds or a minute to compare the color of 30 different little contaminant detection things to this chart. And even then it’s very subjective. Are you reading that your lead is 10 parts per billion or is that closer to 20? That’s a pretty significant difference. The lab kits, you’re filling sample bottles, sending them off to a lab, they’re getting accurately analyzed with proper equipment. And the results that you get back are telling you exactly what they found.

CHRISTINE: So stepping back a little bit from test kits and the filters themselves, most municipal water supplies, public water supplies, they are regulated by the EPA. So the water leaving treatment plants must meet certain quality standards. So I guess, I want to know just big picture, why do people filter their water? What are the concerns you hear most often from readers about filtering?

TIM: It sort of breaks into two camps. One what’s called aesthetic concerns, at least by NSF/ANSI, who devised these tests. Aesthetic concerns is basically taste, most of the time that boils down to chlorine in the water. Utilities very often use chlorine compounds to get rid of microbes in the water, and it leads to that swimming pool taste in your water. And most filters will get rid of that, no problem at all.
Then the other half are, I guess, what we can call sort of more serious contaminants that do have health impacts and people are filtering their water because they’re worried about them. It tends to follow the headlines. So the Flint lead crisis and then the Newark lead crisis. Lead was on everybody’s mind. More recently, it’s been microplastics and PFAS. So it’s possible that your water will contain these things It’s also very, very possible that it doesn’t contain them.

CAIRA: So on a really basic level, can you explain how municipalities clean water in the first place?

TIM: Yeah, there’s a number of different ways they do it. I think step one is typically that they add a flocculant to it, which basically makes solids in the water settle out. And then for decontamination, that can include running ozone through the water. It can be UV light treatment and chlorination are really common ones. And then for some things, they will actually filter it in the sense that we understand it, like run it through activated carbon is probably the most common material that they use.

ROSIE: So this is a perfect segue to a personal question, which is do you filter your water, Tim?

TIM: I do not.

ROSIE: And why?

CAIRA: Also, where do you live?

TIM: Right. I live in New York and splitting time between there and the Jersey Shore, I did filter my water for a long time. Part of that was just for Wirecutter reasons, just for long-term testing some of our picks. But I stopped filtering it several years ago after I got the water in New York tested. I’ve had it tested multiple times with send-away kits and I also used some of the little dip strip ones. And it came back extremely clean. There were very, very low levels of a few things found in it. And for me, they were so low that as a health concern, it just wasn’t big enough to make me want to go through the hassle or continue going through the hassle of filtering my water. And then after my wife and I bought this house in New Jersey, had it tested again. And again, very low levels of a few things, very low levels of PFAS, And similarly, I’m comfortable with that risk.

CHRISTINE: That’s a good point about risk. Because everyone kind of has a different tolerance for risk depending on what your personal situation is. So I also live in New York City. I know we have great water. I do filter my water though because I think I have a lower tolerance to risk. Can you talk a little bit about how that plays into water filtration?

TIM: That’s really it. A filter is not going to do anything bad to your water. So you’re not adding to your risk by using one. And if it’s important to you to just know basically that if there are any of the things that this filter is certified for in my water, they will then be gone or greatly reduced after I filter it, then go ahead.

When I began working on the water filter guide, looking back, I think the mere existence of things like Brita pitchers just sort of convinced me that these things are doing something and it’s something that’s quite necessary. And it took a long time and an awful lot of reporting, a lot of it prompted by the Flint and Newark lead crises, and then PFAS and microplastics. Looking into the United States water supply at like the utility scale, like what is actually being done to water before it’s delivered to homes. And through that and through really closely reading the reports on where are these things problems, what levels are truly a health risk. All of that combined to make me comfortable saying, you know what? Actually I think this water is fine and there are other health factors that I can control in my life that are much more important. But that’s a luxury to be able to have 10 years to do that.

CHRISTINE: What’s the first step that someone should take to determine whether they should get a filter? You mentioned water tests. How expensive are those and is that the first place you’d start?

TIM: It’s not the first place I would start. If you’re on a utility, if you’ve got a utility bill or your apartment building gets a utility bill, that utility has to release at least annually what’s called a consumer confidence report. Officially often just called a water quality report. EPA has a site you can go on and if you just type in EPA CCR Consumer Confidence Report, you can go there it’ll tell you who your utility is. Or if you get a physical bill or you pay your bill online, there’s your utility right there and download it and read it. And most of them do a really good job not just of showing what they’ve found in the water, but what it means. They interpret it for you. And that’s a very good, and I think in most cases, sufficient way to know the risk of what is in your water.

CHRISTINE: Is there a step after getting that CCR report that you would want to actually ante up and pay for a test on your home tap water?

TIM: Yeah. The only way to know absolutely what is coming out of your faucet versus what is coming out of the water plant is to get a test that you take at home. If that’s you, we do recommend getting one of these test kits. They tend to cost around $300 for a pretty comprehensive one. That price can go up if you want to look at specific things like forever chemicals. But the report is detailed, the actual analysis is done at accredited labs, and you will know exactly what came out of your faucet.

CAIRA: What if you’re not on a public water supply? I bought a house in a pretty rural area of upstate New York, and it’s on a well system. My understanding is that it’s really up to me to make sure that my water is up to snuff in terms of filtration and drinkability. What do you do in that situation? How do you figure out what’s in your water then?

TIM: Right.So private wells account for, I think, the number is 15%, of US homes. That number surprised me when I learned it. Those are not regulated. So many people who are on well water do get it tested. Some states, their ag extensions will offer well water testing. Lots of people who are on wells live in agricultural areas, so runoff can be a concern. So it’s worth looking to see if your state or ag extension provides testing or subsidizes it. Beyond that, you can get specific well water test kits. We have one in the guide. It’s the simple lab tap score well water test.

ROSIE: Water, one of the building blocks of life. And I think many people have the privilege of feeling confident about their water quality. But there’s real inequity at play for folks who worry about the quality of their water and can’t afford to pay $300 or more to get it tested. What are your thoughts on that and what did you find in your reporting?.

TIM: It’s absolutely true, and it’s also true that it took crises to begin to see some change in that. To see funding and attention being paid, particularly on upgrading lead infrastructure. In that case, a basic pitcher filter that does get lead, some of them will also get forever chemicals is probably the most economical choice. And again, it’s not going to harm your water in any way, and if there are contaminants in it that it’s certified for, it will reduce or eliminate them in the water.

ROSIE: And in smaller communities, I imagine the towns might not be able to afford the heavy hitting filtration systems that, say, a New York State, a New York City can afford. So if you feel concerned, if you’re not sure, if you can’t find the information, find the most economical way to feel the safest?

TIM: And that is a real issue with these new regulations as well from speaking with people in the utilities industry. A whole generation of water engineers is aging out, and they’re having a hard time replacing them. So a utility according to the EPA is any system that serves more than some very small number of homes, I think it’s less than 10. And there are thousands of these very small utilities around the country. And yeah, they many times will not have the money or the expertise to meet the new standards, basically. It’s one of those situations where the economical thing may just be to get a good basic pitcher filter or other type.

CAIRA: Can living in a polluted area affect your home tap water? For example, my parents live by this huge international airport and I’m convinced that their water is terrible. It tastes terrible. It feels terrible to shower in. So is it the airport that’s doing that to their water? Is that a thing?

TIM: That’s a big question. Can it? Yes. Does it? Usually I think the answer is no. Pipes are kept pressurized, not just to make the water flow out of your tap at a nice speed, but to keep anything from getting into the pipes if there is a leak. Airports, of course, set off alarm bells because they are a known source of forever chemicals because of the firefighting foam.

CAIRA: It’s a surprise that you’re saying it’s the firefighting foam that is the assumed risk there. Because I just assumed it was everything else that requires planes to move.

TIM: I mean, they’re probably not good, but yeah, firefighting foam, it turns out that PFAS are extremely good at making foams that will spread over fuel fires. And so airports and military bases have used them for decades. They run frequent testing where they’re spraying the foam. And so, airports and military bases are a known assumed source of PFAS, even if they haven’t tested.

CAIRA: Wow. Okay.

TIM: But you are asking about your folks’ place. Most of the time, what’s in your water comes from the water supply itself and where that water comes from. So it could be a reservoir that’s miles away or it could be groundwater.

CHRISTINE: All right. We’re going to take a quick break and when we come back, Tim’s going to break down the pros and cons of each type of water filter and help us understand how to choose the right one for us. We’ll be right back.

CHRISTINE: Welcome back. Tim, earlier in the show you walked us through the reasons why people may or may not want to filter their water. Now we want to get into the filters that people can buy. You have tested a bunch of them. You have tested pitcher filters, the ones that go under your sink and on your faucet. Let’s break each one of those down. Starting with pitcher filters. What should people know about pitcher filters and is there a type of person that you would recommend these for?

TIM: I guess, the first thing to know is that pitcher filters, and faucet filters, and under sink filters, the standard ones, are basically variations on a theme. But taking the pitcher filter to start with, it’s what’s known as gravity-fed filtration. The filter itself contains activated carbon and ion-exchange resin, which sounds kind of fancy and scary. It’s just a material that will selectively capture metals in the water like lead or mercury, and then it kicks out typically a sodium ion, which is already in your water. That’s what’s in mineral water. And so pitcher filters, why should somebody get them? They’re the least expensive. They generally do a pretty good job. They’re very convenient. And upkeep tends to be fairly simple.

CHRISTINE: And what’s the downside of a pitcher filter?

TIM: I guess, number one, you do have to lift them in and out of the fridge, or at least in and out of the sink. And even a 9 or a 12-cup pitcher, I think that weighs 9 or 10 pounds, right, and so you’ve got to be doing that a lot. The other, I think, main factor is that the filters do have a tendency to clog. Basically the combination of gravity is not a very strong force, so there’s not a lot of force basically pushing the water through the filter. Sediment in the water can clog the filters. And actually a big problem is the little bubbles from your aerator will clog them up. You can avoid that by not blasting the water right into the filter itself.

CHRISTINE: And who would these be best for?

TIM: If I were continuing to filter my water, they’re what I’d use just because of the convenience, I think. In particular, not just pitchers, but many of these filters can also be installed in a dispenser that will go in your fridge, it holds more water. You can actually filter a whole tankful of clean water and then fill the top again with – lets call it dirty water. Keep it in your fridge, and then as you get water out of it, the stuff in the top just filters back down through. So you get a nice, essentially constant supply of filtered cold water.

CHRISTINE: And these are also kind of more affordable than some other options, right?

TIM: Yeah, considerably.

ROSIE: So how about under-the-sink and faucet-mounted filters, Tim. What are those pros and cons, and for whom might they work best?

TIM: The pro really is kind of a mechanical one. They use the water pressure in your pipes to force the water through the filter, and that means that the filter itself can be made more dense, which has the effect of allowing them to remove a wider range of contaminants. So if you look at the list of what even the best pitcher filters are certified to remove versus a faucet or an under-sink, the latter are going to be removing sometimes twice as many contaminants as the pitcher. Downsides are you have to install them. Just taking the faucet-mounted filters, one drawback is that they can’t be installed. If you have a pull-down sprayer, you need to have a standard, I don’t know, solid faucet.

When you install them, you now have this little outboard motor-looking thing hanging on your faucet all the time. In order to get the filter water, you have to flip a little switch or lever so that you’re sending water through the filter and then to get unfiltered water like for washing your dishes, you have to flip it back. That’s not that big an ask. But if you leave it so that the water’s going through the filter and then you accidentally run hot water through it, you can ruin the ion-exchange resin. And now if you have lead or other metals in your water, it’s not going to capture them.

Most, not all, but most under-sink filters go to a separate faucet, so you don’t have to worry about accidentally running the hot water through it because you will only connect it to the cold water line under your sink. The under sink filters tend to have slightly higher certifications. I know that’s true for our picks. It may be kind of marginal, but it’s just because they have bigger filters that mean that the water spends more time in the filter, travels a longer path as it goes through. And it just improves its ability to capture whatever’s in the water.

ROSIE: I imagine a pro is that you’re getting it through your faucet, so it’s on demand, it’s fast. You’re not waiting for the Brita to filter out and get your filtered water six minutes later. It’s instantaneous. Not really?

TIM: I was going to say-

ROSIE: Is it not?

TIM: Well, on demand is the term that they use. I think it’s probably not going to be annoying typically for filling a cup, but if you’re wanting to fill a pot to make spaghetti and you’re getting half a gallon a minute, it takes a long time to fill a pot. The other advantage to both of these to faucet mount and under sink is that because they have these physically larger and more dense filters, they tend to have a considerably longer lifespan. So in the hundreds of gallons versus typically 30 or 40 for a Brita type filter, so you don’t have to replace the filters as often. The filters are considerably more expensive, so it probably kind of washes out in the end, but you don’t have that maintenance nearly as frequently.

ROSIE: So what are the Wirecutter picks for under-the-sink and faucet-mounted filters?

TIM: It’s the Aquasana AQ-5200 for under sink, and the upgrade pick the AQ-5300+. The price fluctuates wildly basically, so that they’re constantly going on sale. But you’re looking at $100 to, I think, sometimes it’ll go up to as much as $180.

CAIRA: But that’s not bad.

TIM: It’s not bad, but like wait around for it to drop again because it will.

CAIRA: Right. It always will.

TIM: Yeah. And then for the faucet mount, it’s the PUR PLUS Faucet Filter. I think it’s $50.

ROSIE: Tim, you’ve also reviewed this popular filter, the Big Berkey. I’ve seen it. What is it and what’s your take on it?

TIM: It’s basically a really large Brita type filter. So it’s gravity-fed, got a big tank in the top. You’ve got some filters, water flows through that, fills in a tank in the bottom. Our take on it is physically they’re very, very big. They take up an awful lot of room. The filters have this exceptional lifespan. I think it’s 3,000 gallons per filter, and they have two. So you’re looking at 6,000 gallons before you need to replace them. The downside of that is that they breed algae and bacteria to the point that this is a known issue. Also, they are not certified. For the Big Berkey itself, I actually spoke with the gentleman who runs a lab in New Jersey who did the testing and he was very open in saying, yeah, we were not able to and did not test them to the NSF standards.

I think for most people, you can get just as good performance for a lot more convenience and not having to clean gunk off your filters constantly with one of our other options.

CAIRA: Can we talk about some more homeopathic water filtration methods? My brother has these weird charcoal sticks just sitting in his water pitchers in the fridge.

ROSIE: Whoa, whoa, whoa. I had those too.

CAIRA: Okay. Well, I’m still going to call them weird. I’m pretty sure they don’t do anything, but I’m not the expert. Can you just talk about some stuff like that.

TIM: Good news on the floating charcoal front, I do plan to actually do some very basic sort of side-by-side testing of that. I think that they likely don’t do anything. Basically because yes, it’s charcoal, but unless the contaminants are actually coming in contact with it, charcoal is not going to do anything and there’s no reason for the water to really be flowing through this solid object or porous object that’s floating in your pitcher. For filters to work the water, in some way needs to be forced through the filter so that any contaminants come in contact with the filter media.

CAIRA: It’s not just going to be drawn to this floating charcoal stick in the water? Just like-

TIM: I don’t think so. I don’t think so. Also, I think if it is doing something, I think a lot of the immediate effects would be on the taste of chlorine, but chlorine off gases from water very quickly anyway.

CHRISTINE: You can just leave a pitcher of water out overnight and most of that chlorine will go away. Right?

TIM: Yeah.

CHRISTINE: So, Tim, for listeners to this episode, if they’re going to walk away with one thing to know about water safety in their home, what do you think it should be?

TIM: I think it’s that you can sometimes just for free really know basically what’s in your water and knowing what’s in it will help you choose the right filter and the right amount of filtration that you need if you decide that you want to filter. Or you may learn that your water is actually fine or fine enough for you and you decide not to filter. It’s really just the not knowing combined with these, frankly, really alarming headlines that keep popping up that concerns me about this. And I just want people to know that they don’t have to be uncertain of what’s in there and what they can do about it.

CAIRA: Well, Tim, we are at our last question. What’s the last thing you bought that you’ve really loved?

TIM: Can I say I think I’m going to love it?

CAIRA: Yeah, let’s see it.

CHRISTINE: Oh yeah, that counts.

CAIRA: Yeah.

TIM: I bought off of Craigslist-

CAIRA: This is going to be good.

TIM: … belt and disc sander on Friday. It’s for sanding wood and metal, and they’re really useful for woodworking projects and good ones tend to be really expensive, but this one was not very expensive. It was a Craigslist deal. And I thought that is worth risking the health of my spine to lug it down to my basement, which I did, and it will never leave.

ROSIE: Love it. Thank you so much, Tim. Shout out to Craigslist. Hope to see you soon.

TIM: You too. This was fun.

CHRISTINE: Bye, Tim.

CAIRA: Thank you.

CHRISTINE: Well, Tim was lovely as always. What did you guys take away from this episode?

CAIRA: I think that I’m going to check my Consumer Confidence Report, aka the Annual Drinking Water Quality Report. And it’s definitely going to say that my water is fine, which means that I am good to go. I am not going to do anything. I’m going to keep drinking straight from the tap.

ROSIE: The confidence.

CHRISTINE: I hope you put it in a glass first, but if you must.

CAIRA: It depends on the day and the night.

ROSIE: Yeah, I think I felt pretty good after that episode. I think I might get a Brita again. I had one years ago, and I think I might reinvest, and what I like about it is that it is a fairly low barrier to entry for folks. So if you do have concerns about your water, the taste of it, what might be in it, it’s a good starting place.

CHRISTINE: Yeah. I am still very much team filter my water, even though I know that the water in New York City is safe to drink. I have an under-sink filter. I love it. One other thing I took away from Tim is that proximity to pollution doesn’t necessarily mean that your water will be polluted. I think I always kind of assumed, similar to you, Caira, that if you live near some kind of very polluted area, like an airport, like your parents, that you might have a problem with your water. But it really comes down to your water source and how the water is treated, so that’s at least something I can feel good about.

ROSIE: Bit of a comfort.

CHRISTINE: Yeah.

ROSIE: Well, if you want to find out more about Wirecutter’s coverage or Tim’s reporting, if you want to check out any of the products we recommended today, check out our website or you can find a link in our show notes. If you listen every week and you like it, we hope you subscribe and we appreciate you listening.

CHRISTINE: Bye.

CAIRA: Bye. The Wirecutter Show is executive produced by Rosie Guerin and produced by Abigail Keel. Engineering support from Maddie Masiello and Nick Pitman. Today’s episode was mixed by Katherine Anderson. Original music by Dan Powell, Marian Lozano, Alicia Baetup, Katherine Anderson, Rowan Niemisto, and Diane Wong. Cliff Levy is Wirecutter’s deputy publisher and general manager. Ben Frumin is Wirecutter’s editor-in-chief. I’m Caira Blackwell.

CHRISTINE: I’m Christine Cyr Clisset.

ROSIE: And I’m Rosie Guerin.

CAIRA: Thanks for listening.

ROSIE: Well, to your point, Christine, too. I don’t know what I just called you. The Britter, Britter… Jesus, I’m so sorry guys. Hang on.