What to Look for When Buying a Water Filter

What to Look for When Buying a Water Filter

By Marshall Bright

Water Filtration Systems For Your Faucet


There are two reasons to get a water filtration system, explains Rick Andrew of NSF International, a health and safety standards testing company that certifies water filtration systems. Because drinking water in the U.S. is generally very safe, it’s more likely that you’ll want a water filter to improve taste or remove hard minerals and protect your pipes; hard water (i.e., water with high mineral content) can damage pipes and water fixtures with buildup.

However, there are still times when you may want a system that can filter out more dangerous contaminants like lead or man-made chemicals that are increasingly present in our water. If you are on well water, have old pipes, or live in an area with unsafe drinking water, you may need a water filter to remove contaminants like lead or to remove actual particles like sand. 

If you are on city water, you can look at the annual water reports to see what kinds of contaminants are in that water. Even if your municipal water is safe, you may have old pipes that could be leaching contaminants into your water. Adding a water filter can help remove those impurities. Filters certified to remove chlorine, for example, can also encourage hydration by making water more enjoyable to drink.

Independent Certifications 

Because effective filtration is so important (and because it’s so hard to actually be able to tell if it’s working), certification is one of the only ways you can actually be sure your water filter is removing the contaminants its packaging claims it is. The NSF, where Andrew works, is one certifying body. Other certifications to look for are the American National Standards Institute (ANSI) and the Water Quality Association (WQA). There is no one-size-fits-all certification, so it’s important to know what you want removed from your water. For example, the NSF offers certification for removing a certain amount of chlorine and a separate one for removing lead. The more certifications a filter has, the more contaminants it can remove. 

Andrew cautions that you just need to make sure it’s actually certified. Marketing jargon to look out for is things like “filters to NSF standards,” which does not mean it has been independently tested. An earlier version of our list included several water filters that were removed based on similar language that made it unclear whether they were independently tested.


You will also want to consider your household’s water consumption when purchasing a filter. A smaller pitcher for a dorm or apartment, for example, may be fine. But for larger households (or if you want to filter water for cooking as well as drinking), faucet or under-sink filters may make more sense. Refilling a pitcher doesn’t take a huge amount of time, but if you need to do it several times a day, it can be easy to give up on it and simply go back to drinking unfiltered water from the tap. 

Replacement Filters

Filter cost is another thing to consider. A water filtration system is only as good as its filters, so be sure to factor them in, including price, availability, and how often they need to be replaced when deciding on your filtration system.


Water filtration systems can either cost thousands of dollars or, if you’re getting a small pitcher, around $20. The good news is that both systems can effectively remove contaminants from the water. You can get an affordable water filter for personal use without spending much—but make sure to look for certifications. Also, consider the cost of the water filter and how often it will have to be replaced when deciding what you want to spend. 

Types of Water Filters

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When we think of water filters, a pitcher is the first thing that comes to mind, but water filters can be used at almost every point of water’s journey through your home. 

Whole-Home Systems 

Whole-home systems filter all the water coming into your home. The most common kind, says Andrew, is a water softener that will help remove minerals and “soften” your water. Since hard water is bad for pipes and water fixtures, a whole-house filtration system makes the most sense. Because this type of system filters water for the whole house, it’s often expensive and time-intensive to set up. 


If you are filtering for contaminants or taste in your drinking water, a point-of-use filter is also an option. These can be filters that attach to the sink or under the sink where you get drinking water. Andrew emphasizes that whole-house filtration, unless you are on a well, is generally only for softening water, and that these point-of-use systems are sufficient if you’re filtering out contaminants. Under-sink filters are often easier to install than whole-home systems, but are more expensive than faucet attachments or pitchers. 

Faucet Attachments 

Like under-sink filters, faucet attachments offer instant access to filtered water at a place where you would be getting drinking water, such as the kitchen sink. These filters can typically be attached to most standard sinks, though they won’t work with more unique sink setups, like a pull-down faucet with a spray nozzle. A faucet attachment will typically allow you to filter only the water you want to drink, and let unfiltered water come through for things like washing dishes. If your water is safe and you are only filtering it to improve taste, this should be sufficient. This type of system also puts less pressure on the filter by only filtering the water you need. 


Pitchers don’t offer the convenience of a sink filter because they need to be refilled. But, Andrew points out, some people prefer pitchers because they allow you to chill filtered water, which can make it more enjoyable to drink. It’s also the easiest to set up. Furthermore, if you are only filtering water for taste, you may find a faucet filter to be bulky and unnecessary while you do things like wash dishes or your hands at the sink. But, again, this comes down to preference, and both faucet attachments and pitchers are capable of filtering out contaminants. 


Countertop water filtration systems work similarly to faucet filters by diverting water from the sink into a filtration system with its own tap. Other countertop filtration systems need to be filled, acting like water coolers; these can be bulkier than pitchers, but require less frequent refilling. They do offer the advantage of allowing you to place filtered water anywhere in your home, away from a water source. 


Water bottles can also filter water and thus be certified by the NSF and ANSI. They can filter water as you fill the water bottle or as you drink it. Water bottles can be a great option if you want to drink filtered water on the go, and they’re a great alternative to buying water bottles. But many home water filtration brands and filters are designed to remove contaminants from treated water. If you want a water filter for hiking or getting water from sources like creeks and rivers, you’ll need to be extra sure that the filtration system you’re buying can remove bacteria and other organisms found in nature. 

While filters of all types can do a great job of removing contaminants, Andrew adds that no filter can actually remove all contaminants. Any filter that claims it can remove all or 100 percent of contaminants is misrepresenting itself, and no certifying body would verify those claims. The technology just doesn’t exist, says Andrew. 



Nowadays, the term “Brita pitcher” has basically come to mean a filtered water pitcher. Brita’s filters all come with NSF certifications, and its pitchers are popular for their ease of use: drop a filter into the pitcher and you’re good to go. Brita also offers a wide array of pitchers and filtration systems, including faucet filters and water bottles. Brita does not offer under-sink or whole-home filtration systems, however. And not all Brita filters are created equal: Depending on what you want filtered out of the water, make sure to check for those certifications. 


Pur and Brita offer very similar products: basic filters that remove contaminants for taste as well as for mercury and other contaminants, and more expensive filters that can also remove lead and an even higher percentage of contaminants. Pur does offer the most certifications in its basic and more expensive filter. 


APEC offers a whole-house filtration system in addition to countertop filtration systems. The company’s whole-home systems are designed to remove things like odor and chlorine, as well as minerals that can cause scaling on appliances. 


Water filter systems, no matter the size or type, are not a one-and-done purchase. Filters don’t last forever; they’ll eventually stop effectively filtering water. This can have two effects, Andrew says. For starters, the water can start to flow more slowly through the filter itself. More seriously, the filter can also stop effectively filtering water, letting the contaminants stay in the water. Filters all come with a lifespan on them, from a few months to a few years. NSF certifications test to ensure that the filter can continue to remove contaminants for as long as its listed lifespan and even allow for a little bit of time on the end. 

“But, at some point, it’s just not going to work anymore,” Andrew says. Replacing your water filter per manufacturer instructions is just as important as purchasing the right filtration system in the first place. 


As brands try to set themselves apart in the filtration space, different accessories and add-ons have popped up, like Bluetooth capabilities and sensors to monitor filter effectiveness. While these can be appealing bells and whistles, they are not necessary. If you follow manufacturer guidelines on replacing filters, for example, the sensor is unnecessary. Ultimately, what matters is if the filter itself is capable of removing the impurities you want removed. 


Which water filters remove the most contaminants?

While there are a variety of water filtration systems, no one type is inherently better (or worse) at filtering out contaminants. The same types of filters can remove different contaminants depending on how it was manufactured and certified. This is why Rick Andrews recommends knowing what kinds of contaminants you want to be removed, rather than simply looking for a filter that removes a lot of contaminants. If you are unsure of what is in your local water, you can get a water report. 

Do water filters remove bacteria? 

NSF certifies filters that remove bacteria under a standard called P231, says Andrews, but those tend to be designed for activities like camping, when you may need to drink water from a stream. Both city and well water are at relatively low risk of being infected with bacteria. In city water, residual disinfectants like chlorine kill bacteria. Sometimes, damage to pipes can cause bacteria to infect water supplies, leading to a boil water advisory. Boiling water will kill any bacteria, though it won’t remove containments like lead. If you have specific concerns about bacteria in your drinking water, be sure to buy a filtration system certified specifically to remove bacteria. 

Can you filter any type of water? 

In short, absolutely. Water filters can be used for city and well water, and on both soft and hard (high mineral level) water. Just be aware of what you are hoping to remove. A whole-house system specifically designed to remove minerals from hard water, for example, won’t work the same as a pitcher that removes chlorine for flavor. 

Do water filters remove fluoride? 

Fluoride is added to drinking water in most cities in the U.S. to help prevent tooth decay. Some people want filters that will specifically remove it, others may want a filter to remove other contaminants, but leave fluoride. If you have a preference, be sure to check your filter’s certification. 

How long do water filters last? 

Water filtration systems are only as good as the filters within them. Nearly all are designed to be replaced, and all certifications are done with the life of the filter in mind. So, if your filter needs to be replaced every six months, NSF will test each filter to ensure a six-month lifespan. If filters are replaced regularly, the filtration system itself can last for years. 

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