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

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The 3-Stage Under-the-Sink 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

Clearly Filtered 3-Stage

Filtration Capacity:2,000 Gallons
NSF Standards:42, 53, 401
Annual Cost:$$$

Our Rating

Get 15% Off! Use Code: CFBOS5

Clearly Filtered 3-Stage – Key Features

The sophisticated filtration process of the Clearly Filtered 3-Stage has been tested and verified by EPA-accredited laboratories against NSF standards 42, 53 and 401 – with success. The under sink water filter system reduces

  • 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%) and other chemicals
  • Radiological contaminants
  • Dozens of herbicides and pesticides including Glyphosate (up to 99.9%)
  • 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 testing we have ever seen!

How can the Clearly Filtered achieve such outstanding results? We are not 100% sure to be honest.

What we know is that filter stage 1 (made in USA) uses coconut shell-based granular activated carbon – which is nothing special really.

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

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

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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


CF 3-Stage 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.

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 screw off the old and screw in the new!

And lastly, the Clearly Filtered under-the-sink water filter system comes with a 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
Clearly Filtered 3-Stage

The Clearly Filtered 3-Stage – learn more on


As we said, the under sink unit 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 3 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).


For additional guidance on how to install the system, check out this helpful video tutorial:

The Package (Parts)

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

Filter Replacements

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.

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.


Sorry, there is no manual available online.

CF 3-Stage Cons

Compared to other under sink 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 15 to 25 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.

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

After looking into the Clearly Filtered 3-Stage Under-the-Sink Filter System 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. 5 stars!

The Clearly Filtered 3-Stage is best for people who want the most effective non-RO under sink drinking water filter.

Get 15% Off! Use Code: CFBOS5

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This completes our Clearly Filtered 3-Stage review. If you have any questions please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald has been with BOS since the very beginning. She is head of content creation and has fully immersed herself into the home water treatment industry only to become an expert herself. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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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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