Waterdrop TK-FS
The Waterdrop with fluoride filters in the box. Costs $80 more than the TK-A, which can take fluoride filters as an add-on.
Amazon $239.99$239.99
The Waterdrop TK-FS is the better gravity water filter overall, rated 3.3 to 2.6. The Waterdrop TK-FS leads on value, running cost and certification. The Waterdrop TK-FS costs $127.01 less ($239.99 vs $367).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
Big Berkey
#14 in Up to 2.25 galFull review
The best known countertop gravity filter, sized for a small family. Priced well above lookalikes with the same capacity.
Amazon $367$367
Which should you buy?
- Choose the Waterdrop TK-FS for value ($106.66 per gallon of capacity ($239.99, 2.2 gal) vs $163.11 per gallon of capacity ($367, 2.2 gal)), running cost ($0.012 per gallon filtered ($34.99 per element, 3,000 gal each) vs $0.047 per gallon filtered ($140.94 per element, 3,000 gal each)) and certification (states certification to NSF/ANSI 42, NSF/ANSI 372 vs testing claims only, no certification).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every up to 2.25 gal gravity water filter; a clear win is highlighted. How we rank explains each one.
| Factor weight | Waterdrop TK-FS | Big Berkey |
|---|---|---|
| Overall rating | 3.3/5 | 2.6/5 |
| Value 25% | 53 $106.66 per gallon of capacity ($239.99, 2.2 gal) | 27 $163.11 per gallon of capacity ($367, 2.2 gal) |
| Running cost 15% | 75 $0.012 per gallon filtered ($34.99 per element, 3,000 gal each) | 34 $0.047 per gallon filtered ($140.94 per element, 3,000 gal each) |
| Capacity 15% | 17 2.2 gal tank | 17 2.2 gal tank |
| Certification 20% | 40 states certification to NSF/ANSI 42, NSF/ANSI 372 | 10 testing claims only, no certification |
| Element life 15% | 100 3,000 gal rated per element | 100 3,000 gal rated per element |
| Warranty 10% | 11 1-year warranty | 11 1-year warranty |
Independent tests
Waterdrop TK-FS
No independent test published yet.
Big Berkey
| Tested by | Conditions |
|---|---|
| Water Filter Guru | Reviewers calculated 0.75 gal/hr with two Black Berkey and two PF-2 fluoride elements installed (volume and time not given). Tap Score lab tests of city tap water found aluminum 0 ppm before and 1.44 ppm after at 50 gal, then 0.052 ppm before and 0.069 ppm after in a second test with over 100 gal run through the fluoride filters; no TDS reported. Date is the review update date. |
Specifications
| Waterdrop TK-FS | Big Berkey | |
|---|---|---|
| Capacity and flow | ||
| Tank capacity | 2.2 gal | 2.2 gal |
| Price per gallon of capacity | $106.66 | $163.11 |
| Elements included | 4 | 2 |
| Maximum elements | 4 | 4 |
| Flow, fully loaded | - | 7 gal/hr |
| Filtration | ||
| Element type | Coconut shell carbon filter (black) | Black Berkey carbon-media element (BB9-2) |
| Certified | NSF/ANSI 42, NSF/ANSI 372 | Tested only |
| Certification detail | Listing: system certified to NSF/ANSI 372 and the black carbon filter to NSF/ANSI 42. The listing does not say the fluoride filters are certified. | Berkey states Black Berkey Elements were tested by accredited third-party labs against ANSI/NSF protocols for 200+ contaminants. The elements are not NSF/ANSI certified. |
| Fluoride | Included | Add-on filter |
| Fluoride element life | 1,000 gal | - |
| Running cost | ||
| Rated life per element | 3,000 gal each | 3,000 gal each |
| Replacement element | 35 $ | 140.9 $ |
| Cost per gallon filtered | $0.012 | $0.047 |
| Build | ||
| Material | 304 stainless steel | 304 stainless steel |
| Height | - | 19.2 in |
| Diameter | - | 8.5 in |
| Warranty | 1 year | 1 year |