A lower priced three stage big blue system for city water. Running cost is hard to judge without a gallon rating.
Amazon $254.99The Waterdrop WHF3T-PG is the better whole-house water filter overall, rated 3.2 to 3.1. The Waterdrop WHF3T-PG leads on flow and price. The 3M Aqua-Pure AP904 wins on warranty and certification. The Waterdrop WHF3T-PG costs $166.19 less ($254.99 vs $421.18).
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.
The AP903 with scale inhibitor added, for city water that is both chlorinated and hard.
Amazon $421.18Which should you buy?
- Choose the Waterdrop WHF3T-PG for flow (15 gpm service flow vs 10 gpm service flow) and price ($254.99 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 | Waterdrop WHF3T-PG | 3M Aqua-Pure AP904 |
|---|---|---|
| Overall rating | 3.2/5 | 3.1/5 |
| Running cost 25% | 50 filter cost or capacity not published (neutral score used) | 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% | 68 $254.99 | 38 $421.18 |
| Warranty 15% | 0 1-year warranty | 100 25-year warranty |
Specifications
| Waterdrop WHF3T-PG | 3M Aqua-Pure AP904 | |
|---|---|---|
| Filtration | ||
| Capacity | 100,000 gallons | 100,000 gallons |
| Replacement filters or media | - | $347.15 |
| Running cost | - | $3.47 per 1,000 gal |
| Stages | 3 | 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 |
