SLF Water Filtration Comparison · 2026
Moen F9900 4-Stage RO
A strong choice for homeowners who prioritize independently certified contaminant reduction over maximum GPD or a compact tankless design.
Waterdrop G3P800
A strong premium choice for larger households that want substantially more output than the G3P600 while keeping a tankless footprint and adding built-in UV sterilization.
Waterdrop G3P800
Choose the G3P800 if you want 800 GPD, UV sterilization and a more efficient 3:1 pure-to-drain ratio; choose a lower-capacity system if price matters more than maximum output.
RO Performance & Ownership
Compare RO output, filtration stages, remineralization, contaminant evidence, certifications and ownership cost.
Certification & Testing
Exact-model evidence recorded in the SLF database.
| Evidence | Moen F9900 4-Stage RO | Waterdrop G3P800 |
|---|---|---|
| NSF/ANSI 42 | Certified / Listed | Certified / Listed |
| NSF/ANSI 53 | Certified / Listed | Certified / Listed |
| NSF/ANSI 58 | Exact System Certified | Exact System Certified |
| NSF/ANSI 401 | Certified / Listed | — |
| NSF/ANSI/CAN 372 | Certified / Listed | Certified / Listed |
| IAPMO | Certified / Listed | Certified / Listed |
| Testing Organization | IAPMO R&T | IAPMO R&T |
Which Is Right for You?
Moen F9900 4-Stage RO
Best for: Homeowners who want a traditional under-sink RO system with unusually strong exact-model certification and contaminant-reduction evidence
Waterdrop G3P800
Best for: Large households, high daily water use, tankless under-sink installations, PFAS concerns, and shoppers wanting UV plus smart water-quality monitoring.
Consider if: High Daily Output, Want TDS Display
Our Recommendation
Moen F9900 4-Stage RO
Strong certified under-sink RO option for homeowners prioritizing evidence-backed filtration.
Waterdrop G3P800
The Waterdrop G3P800 is worth considering for high-use households that want a premium tankless RO system with fast output, UV sterilization and smart monitoring. Its biggest drawbacks are price and the lack of built-in remineralization on the standard model.
The Short Answer
Choose the Moen F9900 if exact-model certification depth and broad contaminant evidence matter more than maximum RO output or low annual filter cost.
Choose the G3P800 if you want 800 GPD, UV sterilization and a more efficient 3:1 pure-to-drain ratio; choose a lower-capacity system if price matters more than maximum output.
Water Filter Comparison FAQs
Answers are generated from the current SLF product records for these two systems.
Which is better, Moen F9900 4-Stage RO or Waterdrop G3P800?
Waterdrop G3P800 is the overall pick for this specific matchup. Choose the G3P800 if you want 800 GPD, UV sterilization and a more efficient 3:1 pure-to-drain ratio; choose a lower-capacity system if price matters more than maximum output.
Which system has the higher daily filtration capacity?
Waterdrop G3P800 has the higher rated output: 800 GPD versus 27.5 GPD.
Which system offers remineralization?
Both systems are listed as no for remineralization in the current SLF records.
Which system has the lower MSRP?
Moen F9900 4-Stage RO has the lower MSRP in the current SLF records at $545.35, compared with $999.00 for the other system.
Do both systems require a plumbing connection?
Moen F9900 4-Stage RO: Yes. Waterdrop G3P800: Yes.
Which system is more renter friendly?
Moen F9900 4-Stage RO: No. Waterdrop G3P800: No. Check lease and plumbing-modification rules before installing an under-sink system.
What certifications are listed for these systems?
Moen F9900 4-Stage RO: Exact F9900 system with F9910, F9920, F9930 and F9940 is certified by IAPMO R&T against CSA B483.1, NSF/ANSI 42, NSF/ANSI 53, NSF/ANSI 58, NSF/ANSI/CAN 372, NSF/ANSI 401 and NSF Protocol P231 for the claims enumerated on the Performance Data Sheet. Waterdrop G3P800: Waterdrop identifies the exact G3P800 system as certified by IAPMO R&T to NSF/ANSI 42, 53 and 58 for applicable reduction claims and to NSF/ANSI/CAN 372 for low-lead material compliance.
How do estimated annual filter costs compare?
Moen F9900 4-Stage RO: $383.75. Waterdrop G3P800: $159.97. Actual replacement timing and prices can vary.