Purewell 3-Stage PW-OB
A low-priced, certified-filter 2.25 gal system for chlorine, taste and sediment. Fluoride needs a different model.
Amazon $145.99$145.99
The Purewell 3-Stage PW-OB is the better gravity water filter overall, rated 3.5 to 2.6. The Purewell 3-Stage PW-OB leads on value, certification and capacity. The Purewell 3-Stage PW-OB costs $203.01 less ($145.99 vs $349).
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.
Boroux Compact 1.8 Gal
#13 in Up to 2.25 galFull review
A small stainless gravity filter for one or two people with long-life filters. It costs more per gallon of tank than larger rivals.
Amazon $349$349
Which should you buy?
- Choose the Purewell 3-Stage PW-OB for value ($64.88 per gallon of capacity ($145.99, 2.2 gal) vs $193.89 per gallon of capacity ($349, 1.8 gal)), certification (states certification to NSF/ANSI 42, NSF/ANSI 372 vs states certification to NSF/ANSI/CAN 372) and capacity (2.2 gal tank vs 1.8 gal tank).
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 | Purewell 3-Stage PW-OB | Boroux Compact 1.8 Gal |
|---|---|---|
| Overall rating | 3.5/5 | 2.6/5 |
| Value 25% | 84 $64.88 per gallon of capacity ($145.99, 2.2 gal) | 16 $193.89 per gallon of capacity ($349, 1.8 gal) |
| Running cost 15% | 74 $0.012 per gallon filtered ($36.99 per element, 3,000 gal each) | 71 $0.013 per gallon filtered ($79.50 per element, 6,000 gal each) |
| Capacity 15% | 17 2.2 gal tank | 7 1.8 gal tank |
| Certification 20% | 40 states certification to NSF/ANSI 42, NSF/ANSI 372 | 10 states certification to NSF/ANSI/CAN 372 |
| Element life 15% | 100 3,000 gal rated per element | 100 6,000 gal rated per element |
| Warranty 10% | 0 warranty not published, scored as none | 0 warranty not published, scored as none |
Specifications
| Purewell 3-Stage PW-OB | Boroux Compact 1.8 Gal | |
|---|---|---|
| Capacity and flow | ||
| Tank capacity | 2.2 gal | 1.8 gal |
| Price per gallon of capacity | $64.88 | $193.89 |
| Elements included | 2 | 2 |
| Maximum elements | 2 | - |
| Flow, as shipped | 4 gal/hr | - |
| Filtration | ||
| Element type | Black carbon composite: 0.01 micron UF membrane, silver ion membrane and carbon block | Boroux Foundation Black carbon element, 9.5 in |
| Certified | NSF/ANSI 42, NSF/ANSI 372 | NSF/ANSI/CAN 372 |
| Certification detail | Listing: the black carbon filter passed NSF/ANSI 42 certification and the system passed NSF/ANSI 372. | Filter listing (maker copy): NSF/ANSI/CAN 372 certified by WQA, a lead-free materials standard, not a contaminant reduction certification. System listing: filters tested and independently verified by third-party accredited laboratories, none named. |
| Fluoride | - | Add-on filter |
| Running cost | ||
| Rated life per element | 3,000 gal each | 6,000 gal each |
| Replacement element | 37 $ | 79.5 $ |
| Cost per gallon filtered | $0.012 | $0.013 |
| Build | ||
| Material | 304 stainless steel | 304 stainless steel |
| Height | 20 in | 17.5 in |
| Diameter | 8.9 in | 8 in |
| Weight | 8.5 lb | - |