Review: Clearly Filtered 3-Stage Under Sink Water Filter System

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The 3-Stage Under the Sink Water Filter System by Clearly Filtered provides you with highly pure, safe, and refreshing water right at your kitchen faucet.

The unit is capable of removing up to 99.9% of over 230 different contaminants that might be lurking in your water.

Want to know more? It’s all here!

Clearly Filtered 3-Stage Under Sink Water Filter System

Clearly Filtered 3-Stage Under Sink Water Filter System

Price: $$$
Filter Process: Coconut GAC Pre-Filter, Proprietary Blends
Filter Life: 2,000 Gallons
Flow Rate: Not Specified
Annual Cost: ~$440

Overall Rating: 5.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

Get 10% Off! Use Code: WELCOME10

Clearly Filtered 3-Stage Under Sink Water Filter System – All Specs

  • Model: CF-UTSF
  • Last Price: $550.00
  • Annual Maintenance Cost: $440
  • Filter Media/Process: Coconut Carbon Pre-Filter, Proprietary Blends
  • Filter Stages: 3
  • Flow Rate: Not Specified
  • Filtering Capacity: 2,000 gal
  • WxHxD: 15″x15.4″x3.1″
  • Weight: 6.9 lbs
  • Water Temperature: 38-85 °F
  • Fitting: 3/8″
  • NSF Testing: Standards 42, 53, 401
  • NSF Certifications: Standards 42, 372
  • Warranty: Lifetime (Limited)

Clearly Filtered – Discount Code

You can use our code WELCOME10 to get a 10% discount on any purchase you make on (replacement filters excluded).

Clearly Filtered 3-Stage – Key Features

The sophisticated filtration process of the Clearly Filtered 3-Stage Under Sink Water Filter System has been tested and verified by EPA-accredited laboratories against NSF standards 42, 53, and 401 – with success. The under sink filter has shown to reduce:

  • Chlorine (98.6%)
  • Chloramines (95.3%)
  • Sodium fluoride (90.7%)
  • Aluminum (95.2%)
  • Total arsenic (94.3%)
  • Chromium 6 (99.4%)
  • Lead (98.9%)
  • TTHMs (99.6%), PFOA (99.6%), PFOS (99.8%), and other organic chemicals
  • Dozens of herbicides and pesticides including Glyphosate (up to 99.9%)
  • A bunch of pharmaceuticals (up to 99%)
  • Radiological contaminants
  • More than 100 VOCs and semi volatile compounds (up to 99.9%)

*This is only an excerpt.

Just to clarify, this is some of the most thorough and best testing we have ever seen with a water filter!

How can the Clearly Filtered achieve such outstanding results?

Well, what we know is that filter stage 1 (made in USA) uses coconut shell-based granular activated carbon – which is nothing special really. This is more like a pre-filter that protects the other stages from sediments and that also removes bad tastes and odor as well as some organic chemicals.

All we know about filter stage 2 (made in USA) is that it uses a “special blend” to capture heavy metals, VOCs, pesticides, radiation, and PFAS among other stuff.

Filter 3 applies “Affinity Filtration Technology” to bind fluoride and arsenic. Again, we don’t know much more than that. Clearly Filtered only disclosed that the stage uses proprietary filter media, and that it’s neither activated alumina nor bone char.

Please note: The Clearly Filtered 3-stage won’t take care of any pathogens. Therefore, it’s to be used with tap water or properly disinfected well water.

Alexa’s Video Review

As part of the BOS team, Alexa has installed and tested the Clearly Filtered Under-the-Sink Water Filter System in her own home and with her own hands. She has used the system for several weeks to gather genuine first-hand experience. And most importantly, Alexa has documented the entire process, including her findings and personal opinion, in the video below:

clearly filtered under the sink water filter image 1clearly filtered under the sink water filter image 2clearly filtered under the sink water filter image 3clearly filtered under the sink water filter image 4

I’m going to give this a 5-star because I think that this it is the nicest product you can get for under-the-sink filter. I can’t believe how much different it made my tap water taste coming out of the faucet. (…) on top of that it was super easy to install and I could do it myself.

Alexa Gibbons – BOS Video Content Creator


Clearly Filtered Under Sink Pros

First of all, we appreciate the fact that the under sink system is built in the USA with stainless steel rather than cheap plastic hoses for durability.

Also, it maintains all healthy minerals in the water.

Another plus is the 15-minute non-permanent DIY installation – great for renters and your wallet. By the way, there’s no tank and the unit is only 3 inches thick, so it’s really space-saving.

Maintaining the system is a piece of cake, too. On average, the filters need to be replaced once a year. No tools required here, just twist off the old and screw in the new!

And lastly, the Clearly Filtered under-the-sink filter system comes with a limited lifetime warranty. Plus, you can return it within the first 30 days after purchase in case you are not satisfied and receive a full refund, no questions asked. #PeaceOfMind

What Contaminants Are Being Removed?

The Clearly Filtered 3-Stage under sink water filter system removes a whole lot of contaminants, here are some of them:

  • Sodium fluoride – 90.7%
  • Chlorine – 98.6%
  • Chloramine – 95.3%
  • PFOS – 99.8%
  • PFOA – 99.6%
  • Aluminum – 95.2%
  • Arsenic – 94.3%
  • Cadmium – 96.7%
  • Chromium 6 – 99.4%
  • Lead – 98.9%
  • Inorganic Mercury – 81.8%
  • Gross Alpha (Thorium 230) – 99.5%
  • BPA – 99.0%
  • Estrone – 91.3%
  • Ibuprofen – 95.7%
  • Progesterone – 89.4%
  • DCPA – 99.8%
  • Bentazon – 99.7%
  • Atrazine – 99.9%
  • Butachlor – 99.8%
  • Endrin – 99.8%
  • Diphenylamine – 99.8%
  • Fluorene – 99.8%
  • Diethyl Phthalate – 99.8%
  • Benzene – 99.9%
  • Bromoform – 99.9%
  • Chloroform – 98.4%
  • MTBE – 99.9%

Clearly Filtered 3-Stage Under Sink Water Filter System

The Clearly Filtered 3-Stage – learn more on


Like we said, the Clearly Filtered under sink water filter hooks up in no time without the need for calling a plumber so you can save the extra money.

What’s more, you don’t have to make any permanent changes to your plumbing which is ideal for renters. There’s also no need to drill a hole for an extra faucet or anything.

All you have to do is:

  1. Turn off the water.
  2. Open the faucet to flush out any remaining water.
  3. Disconnect the cold feed water line.
  4. Connect the inlet hose of the filter system to the feed valve and tighten with a wrench.
  5. Connect the outlet hose of the filter system to the faucet inlet hose. Use two wrenches to tighten. 3/8” fittings for both the inlet/outlet hose are already attached.
  6. Turn the water back on.
  7. Flush the system for 5 minutes or as long as it takes for the water to run clear. Done!

You also have the option to mount the system to the side of your kitchen sink cabinet (screws are part of the package).


The Package (Parts)

  • Filter module with mounting bracket and stainless steel hoses
  • 3x filters (already assembled)
  • Mounting screws
  • Instructions


Thanks to their modular design, replacing the filters is super easy (modular meaning there are no housings and you discard of the entire cartridge).

And because there are built-in shut-off valves, you don’t even have to close the feed water supply. You can simply twist off the old filters and twist on the new – no tools required. Then, give the filters a quick flush and you are good to go.

Each cartridge has a filtration capacity of about 2,000 gallons or 12 months. Larger families might have to change filters every 9 months or so, while for a single person they can last as long as 15 months.

Average annual filter replacement cost is pretty high and more than what you pay with the competition: $440.

Tip: If you subscribe to the Clearly Filtered VIP Program you get replacement filters automatically delivered on schedule and save 10% + you get free shipping.


Here is a link to the official manual:

NSF and Other Certifications

The Clearly Filtered under sink water filter is officially certified against two NSF standards – NSF 42 and NSF 372. NSF 42 covers aesthetic chlorine, and taste and odor reduction, while NSF 372 covers the lead content of the filter components.

In addition, the Clearly Filtered has been successfully tested by independent third-party laboratories against NSF standards 42, 53, and 401.

Earlier Product Versions

The CF 3-Stage had an earlier version that looked a bit different, but that’s all — only the looks changed. To our knowledge, all aspects of the filtration process are exactly the same in the previous and current versions.

Clearly Filtered Under Sink Filter Cons

Compared to other under sink water filters on the market, the Clearly Filtered doesn’t come cheap. But that was to be expected. It’s top-notch and not imported from overseas, so of course there is a price difference.

Another minor drawback is the system reducing water pressure by about 25 to 35 percent. To be fair, thorough filtration takes time, and only with sufficient contact time can you ensure that the more stubborn contaminants will be removed from your water. Also, flow rates are usually still fast enough to not become an issue.

Clearly Filtered 3-Stage Review: Our Verdict + Best for

After looking into the Clearly Filtered 3-Stage Under Sink Water Filter System, ordering and testing it ourselves, and reading dozens of customer ratings for it, we are 100% certain that you will be more than happy with what you get. People are particularly happy about the quick, simple install and the clean water taste.

Is it worth the investment? In our opinion, yes. In fact, it’s our go-to under sink water filter. The Clearly Filtered 3-Stage is best for people who want the most effective non-RO under sink drinking water filter in the market. 5 stars!

Our Rating in Detail:

  • Filtration Performance: 5.0/5.0
  • Filter Capacity (Life): 5.0/5.0
  • Purchase Price: 4.0/5.0
  • Annual Cost: 4.5/5.0
  • Overall: 5.0/5.0

Get 10% Off! Use Code: WELCOME10

Comparison to Other Under Sink Water Filters

The Epic Smart Shield Under Sink Water Filter is another popular option in the market; let’s see how the Clearly Filtered 3-stage compares to it.

Epic Smart Shield Under Sink Water Filter

Epic Smart Shield

Price: $
Filtration Process: Activated Carbon Block
Filter Life: 651 gal
Water Flow Rate: 1.25 gpm
Annually: $115

Overall Rating: 4.5/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

Get 20% Off! Use Code: BOSEpic

Clearly Filtered 3-Stage Under Sink Water Filter System

Clearly Filtered 3-Stage

Price: $$$
Filtration Process: Coconut GAC, Proprietary Blends
Filter Life: 2,000 gal
Water Flow Rate: Not Specified
Annually: ~$440

Overall Rating: 5.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

Get 10% Off! Use Code: WELCOME10

The Epic Smart Shield is an inline system (like Clearly Filtered), so you don’t need to install a new faucet. Installation of both systems is easy. But the Epic Smart Shield uses a more simple filtration process featuring just one carbon block. Still, it is NSF-tested/certified to remove 70 contaminants, including lead, mercury, cysts, chloramine, chlorine, turbidity, asbestos, MTBE, VOCs, pharmaceuticals, and BPA.

What’s more, the Epic Smart Shield is more economical to buy and maintain than the Clearly Filtered system. You even get a free replacement filter if you collect and mail back three old filters. Other nice features: A lifetime warranty and satisfaction guarantee.

All in all, we’d say the Clearly Filtered under sink filter system clearly takes the lead with much broader contaminant reduction, but it also costs a lot more. The Epic Smart Shield is cheaper and still effective — a great option if you’re on a budget.

This completes our review of the Clearly Filtered 3-Stage Under Sink Water Filter System. If you have any questions please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment:

Bob says April 6, 2022

Your review states that the Clearly 3-stage filter system removes 99.9% of lead but if you go to the company website ( they state that it removes 98.9% of lead. Please explain this discrepancy.

    Gene says June 15, 2022

    Hi Rob,
    This section was updated. We still had the old reduction rates in our article.

DBS says July 25, 2022

Thanks for a great overview. Can you comment if the Clearly Filtered undersink system removes microplastics, and if so to what extent? Thanks

    Gene says November 22, 2022

    It’s not tested for removing microplastic.

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