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
The 3M Aqua-Pure AP904 is the better whole-house water filter overall, rated 3.1 to 2.6. The 3M Aqua-Pure AP904 leads on certification. The Express Water Essential Pro WH300SCGS-S wins on running cost and flow. The 3M Aqua-Pure AP904 costs $48.81 less ($421.18 vs $469.99).
Express Water Essential Pro WH300SCGS-S
#10 in CartridgeFull review
A tidy, frame mounted three stage system for city water with some grit. Its certification claim is vague.
Amazon $469.99$469.99
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 3M Aqua-Pure AP904 for certification (certified to NSF/ANSI 42 vs no certification in a public listing, no tested to claim).
- Choose the Express Water Essential Pro WH300SCGS-S for running cost ($0.96 per 1,000 gallons ($96.36 every 100,000 gallons) vs $3.47 per 1,000 gallons ($347.15 every 100,000 gallons)) and flow (15 gpm service flow vs 10 gpm service flow).
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 | 3M Aqua-Pure AP904 | Express Water Essential Pro WH300SCGS-S |
|---|---|---|
| Overall rating | 3.1/5 | 2.6/5 |
| Running cost 25% | 0 $3.47 per 1,000 gallons ($347.15 every 100,000 gallons) | 42 $0.96 per 1,000 gallons ($96.36 every 100,000 gallons) |
| Certification 25% | 60 certified to NSF/ANSI 42 | 0 no certification in a public listing, no tested to claim |
| Flow 15% | 50 10 gpm service flow | 100 15 gpm service flow |
| Price 20% | 38 $421.18 | 32 $469.99 |
| Warranty 15% | 100 25-year warranty | 0 warranty not published, scored as none |
Specifications
| 3M Aqua-Pure AP904 | Express Water Essential Pro WH300SCGS-S | |
|---|---|---|
| Filtration | ||
| Capacity | 100,000 gallons | 100,000 gallons |
| Replacement filters or media | $347.15 | $96.36 |
| Running cost | $3.47 per 1,000 gal | $0.96 per 1,000 gal |
| Stages | 1 | 3 |
| Certified | NSF/ANSI 42 | - |
| Chloramine | No | No |
| PFAS | No | No |
| Build | ||
| Flow | 10 gpm | 15 gpm |
| Ports | 1 in | 1 in |
| UV stage | No | No |
| Warranty | 25 years | - |