ProOne Big+ 3 Gal
A 3 gal stainless gravity filter that uses ProOne G2.0 filters. A mid-priced option, though the listing publishes little about flow, filter gallons or warranty.
Amazon $229.95$229.95
3 galNSF/ANSI 42
2.9/5
The middle Berkey for a household that drinks and cooks with filtered water. A step up from the Big Berkey without needing much more space.
- 3.2 galCapacity
- Tested onlyCertification
- 3,000 gal eachElement life
- Add-on filterFluoride
Check price at Amazon$408
Price checked November 9, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- 3.25 gal for a household of two to four
- Four-element capacity for a 7 gal/hr maximum flow
Cons
- 23 in tall, so it needs clear room above the counter
- Listing gives no flow rate for the two included elements
The Berkey family
Every Berkey model we rank, smallest first. Ratings compare each against its own capacity.
| Model | Capacity | Rating | Price |
|---|---|---|---|
| Travel Berkey | 1.5 gal | 2.4/5 | $327 |
| Big Berkey | 2.2 gal | 2.6/5 | $367 |
| Berkey Light | 2.8 gal | 2.8/5 | $335 |
| Royal Berkey (this one) | 3.2 gal | 2.9/5 | $408 |
| Imperial Berkey | 4.5 gal | 3.2/5 | $451 |
| Crown Berkey | 6 gal | 3.5/5 | $478 |
How it scores
The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its capacity. How we rank explains each one.
Specifications
| Model number | RB4X2-BB |
|---|---|
| Capacity and flow | |
| Tank capacity | 3.2 gal |
| Price per gallon of capacity | $125.54 |
| Elements included | 2 |
| Maximum elements | 4 |
| Flow, fully loaded | 7 gal/hr |
| Filtration | |
| Element type | Black Berkey carbon-media element (BB9-2) |
| Certified | Tested only |
| Certification detail | 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 | Add-on filter |
| Running cost | |
| Rated life per element | 3,000 gal each |
| Replacement element | 140.9 $ |
| Cost per gallon filtered | $0.047 |
| Build | |
| Material | 304 stainless steel |
| Height | 23 in |
| Diameter | 9.5 in |
| Weight | 8 lb |
| Warranty | 1 year |
Alternatives in this capacity
Boroux Legacy 3 Gal
A Royal Berkey sized 3 gal stainless filter with long-life carbon filters. A fair price, but the filters lack an NSF reduction certification.
Amazon $399$399
3 galNSF/ANSI/CAN 3726,000 gal each
Berkey Light
A lightweight 2.75 gal Berkey for places where a stainless tank is too heavy to move. Pick it for portability, not price.
Amazon $335$335
2.8 galTested only3,000 gal each
Compare
Compare the Royal Berkey with any other gravity water filter →
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