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Our Verdict (Best For)
The Clearly Filtered is an inline under sink water filter that’s pretty easy to set up, use, and maintain, with a long 2000-gallon filter lifespan. The very steep upfront and long-term costs are somewhat offset by the sturdy, high-quality, space-saving design. However, while the filtered water tasted and smelled great, performance in our lab testing was underwhelming, with 4 contaminants showing no or only partial reduction. And while the Clearly Filtered 3-Stage was thoroughly third-party tested to 100% filter life, it holds only 1 actual NSF certification for contaminant reduction (for chlorine and taste/odor). Factor in the notable number of 3rd-party customer complaints about low water pressure – an issue we didn’t experience ourselves – and there are better options out there at this price.
The Clearly Filtered 3‑Stage is an under sink water filter that connects to your plumbing and installs inline, allowing you to keep using your regular kitchen faucet. It’s designed for use as a drinking water filter and can purify both tap water and properly disinfected well water.
As usual, we’ve tested the system with our own hands:
- Hands-on experience: We installed/assembled, used, and maintained it.
- Filtration effectiveness: We sent an unfiltered and a filtered tap water sample to a professional lab for analysis in order to determine real-life contaminant reduction capabilities. Plus, we checked for NSF certifications and other test data.
- More testing: We performed a taste & odor test and a filtration speed test.
- All other product aspects: We considered initial + long-term cost, product warranties, additional features, frequent customer complaints, etc.
Contents
Final Rating: /5.00
Filtration: /5.00
Usability: /5.00
Costs: /5.00
| Type: | Under Sink Water Filter |
| Price (May 5, 2025, No Short-Term Sales): | $550 (Use Code BOS10 for 10% Off!) |
| Yearly Cost for 1,000 gal Based on Rated/Claimed Filter Life (May 5, 2025): | ~$440 (Save 10% With Filter Subscription) |
(Use Code BOS10 for 10% Off!)
Final Rating: /5.00
What We Like Most
- Filtered water tasted and smelled 100% clean.
- Pretty much fully covered by third-party NSF testing for contaminant reduction and to 100% filter life.
- Easy to set up, prime, use, and maintain also thanks to nice instruction booklet.
- Strong enough water flow for everyday use (you keep using your regular faucet).
- Sturdy, high-quality, space-saving design, with braided metal tubing.
- Limited lifetime warranty (2 years).
What We Don’t Like
- Only 2 NSF certifications for contaminant reduction (chlorine + taste/odor).
- Clearly Filtered doesn’t disclose the exact types of filter media used.
- No filter life indicator.
- Very expensive, more than double the average upfront and annual costs of all the under sink water filters we tested.
- Notable chunk of Amazon customers complained about significantly reduced water pressure.
How the Clearly Filtered 3-Stage Compares to…
18 Other Under Sink Water Filters
In this video, Sara highlights our under sink water filter top picks. The Clearly Filtered 3-Stage was included in our testing, but didn’t make the cut.
Please note: Our full guide on the best under sink water filters is available here.
Video Chapters + Comparison Sheet
- Link to Comparison Sheet
- 00:00 – Intro
- 00:34 – How We Tested & Rated
- 01:53 – Our Recommendations
- 03:01 – Best Overall (Cloud RO)
- 15:11 – 2 Best Tankless ROs (Waterdrop G3P600 & X12)
- 27:26 – Best Non-RO Filter (Epic Smart Shield)
- 31:22 – Highest Filtration Score (Aquasana SmartFlow)
- 32:02 – Made in USA (USWS All American & Home Master TMHP-L)
- 32:34 – Budget RO Pick (APEC ROES-50 Essence)
- 32:51 – AO Smith AO-US-200 & Culligan US-EZ-4
- 33:34 – Summary
Full Analysis of the Clearly Filtered 3-Stage
Filtration: /5.00
1. Lab Results: /5.00
Remember that our before vs after lab comparison is not an exact science. It’s informational and subject to variability, inaccuracies, and interferences caused by natural fluctuations in water quality, accidental contamination, human error, instrumentation issues, and more. Furthermore, our lab-testing is limited to those contaminants present in our water supplies and at their respective concentrations. As such, it can only give us a general idea for how effective a certain water treatment product might be.
Lab Results Chart
| Potentially Harmful | Aesthetic Issues | Feed Water Level | Filtered Water Level | Reduction Rate | |
| Water Disinfectants | |||||
| Chlorine (mg/L) | ✖ | ✖ | 1.22 | 0 | 100% |
| Disinfection Byproducts | |||||
| Bromodichloromethane (µg/L) | ✖ | 2.04 | 0 | 100% | |
| Bromoform (µg/L) | ✖ | 1.86 | 0 | 100% | |
| Dibromochloromethane (µg/L) | ✖ | 2.82 | 0 | 100% | |
| Chloroform (µg/L) | ✖ | 1.07 | 0 | 100% | |
| Metals | |||||
| Copper (mg/L) | ✖ | ✖ | 0.04 | 0 | 100% |
| Barium (mg/L) | ✖ | 0.04 | 0.01 | 75% | |
| Boron (mg/L) | ✖ | 0.06 | 0.04 | 33% | |
| Lithium (mg/L) | ✖ | 0.01 | 0 | 100% | |
| Strontium (mg/L) | ✖ | 0.42 | 0.26 | 38% | |
| Salts | |||||
| Nitrate (N) (mg/L) | ✖ | 1.96 | 1.3 | 34% | |
| Fluoride (mg/L) | ✖ | 0.58 | <0.1 | Anywhere Between 83% and 99% | |
| Other | |||||
| Uranium (µg/L) | ✖ | 1 | 0 | 100% | |
| Impurities NOT Detected in Unfiltered Tap Water Sample | |||||
| Cobalt (mg/L) | ✖ | 0 | 0.01 | ||
| Explanation: | |||||
| Full Removal | |||||
| Considerable Reduction | |||||
| Concentration More Than Double of Unfiltered Water Sample | |||||
| Potential Leaching Reached or Exceeded the Strictest Public Health Guideline We Could Find | |||||
*100% means reduction to below the minimum detection level. To learn more about our testing procedures check our editorial guidelines.
Link to Filtered Water Report
Link to Unfiltered Water Report
Usability: /5.00
Costs: /5.00
Please note: This page is still a work in progress. Additional content and details will be added shortly – stay tuned!
Further Reading
About the Author(s)
Sara has been a lifelong home-improvement fan (she’s been hooked on This Old House since she was five) and taught herself any project she didn’t already know by watching YouTube tutorials. She is also an award-winning filmmaker. Armed with this skillset, Sara installs, primes, samples, uses, and maintains nearly every point-of-use water treatment systems we test – then brings her results to life on camera for our YouTube channel.
Raoul has a background in mechanical engineering and has been writing about home water treatment since 2015. He designs our product review processes, analyzes the results, and ties everything together. As editor-in-chief, he tries hard to keep the whole operation running smoothly behind the scenes.