iSpring WGB22B
#5 in CartridgeFull review
A sensible upgrade on the WGB21B for a family on chlorinated city water, with filters that last longer and cost little per gallon.
Amazon $286.70$286.70
The iSpring WGB22B and the 3M Aqua-Pure AP904 are evenly matched, rated 3.1 and 3.1. The iSpring WGB22B leads on running cost, flow and price. The 3M Aqua-Pure AP904 wins on warranty and certification. The iSpring WGB22B costs $134.48 less ($286.70 vs $421.18).
3M Aqua-Pure AP904
#6 in CartridgeFull review
The AP903 with scale inhibitor added, for city water that is both chlorinated and hard.
Amazon $421.18$421.18
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the iSpring WGB22B for running cost ($0.83 per 1,000 gallons ($82.97 every 100,000 gallons) vs $3.47 per 1,000 gallons ($347.15 every 100,000 gallons)), flow (15 gpm service flow vs 10 gpm service flow) and price ($286.70 vs $421.18).
- Choose the 3M Aqua-Pure AP904 for warranty (25-year warranty vs 1-year warranty) and certification (certified to NSF/ANSI 42 vs tested to NSF/ANSI 42, not certified).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every cartridge whole-house water filter; a clear win is highlighted. How we rank explains each one.
| Factor weight | iSpring WGB22B | 3M Aqua-Pure AP904 |
|---|---|---|
| Overall rating | 3.1/5 | 3.1/5 |
| Running cost 25% | 47 $0.83 per 1,000 gallons ($82.97 every 100,000 gallons) | 0 $3.47 per 1,000 gallons ($347.15 every 100,000 gallons) |
| Certification 25% | 30 tested to NSF/ANSI 42, not certified | 60 certified to NSF/ANSI 42 |
| Flow 15% | 100 15 gpm service flow | 50 10 gpm service flow |
| Price 20% | 61 $286.70 | 38 $421.18 |
| Warranty 15% | 0 1-year warranty | 100 25-year warranty |
Specifications
| iSpring WGB22B | 3M Aqua-Pure AP904 | |
|---|---|---|
| Filtration | ||
| Capacity | 100,000 gallons | 100,000 gallons |
| Replacement filters or media | $82.97 | $347.15 |
| Running cost | $0.83 per 1,000 gal | $3.47 per 1,000 gal |
| Stages | 2 | 1 |
| Certified | - | NSF/ANSI 42 |
| Tested to (not certified) | NSF/ANSI 42 | - |
| Chloramine | No | No |
| PFAS | No | No |
| Build | ||
| Flow | 15 gpm | 10 gpm |
| Ports | 1 in | 1 in |
| UV stage | No | No |
| Warranty | 1 year | 25 years |