SLF Water Filtration Comparison · 2026
VIVA21 5-Stage RO
Recommended for shoppers seeking an affordable traditional under-sink RO system with stronger certification positioning than many budget alternatives.
Waterdrop G3P600
A strong pick for households wanting fast, high-capacity RO filtration in a space-saving tankless system.
Waterdrop G3P600
Choose the G3P600 if you want a high-capacity, certified tankless RO system and are comfortable with under-sink installation.
RO Performance & Ownership
Compare RO output, filtration stages, remineralization, contaminant evidence, certifications and ownership cost.
Which Is Right for You?
VIVA21 5-Stage RO
Best for: Budget-conscious households that want a conventional, certified-positioned under-sink RO system with a storage tank and standard-size replacement filters.
Consider if: Budget Under $200, Low Replacement Cost
Waterdrop G3P600
Best for: Households wanting fast 600 GPD tankless reverse osmosis, a smart faucet, and independently certified RO performance.
Consider if: High Daily Output
Our Recommendation
VIVA21 5-Stage RO
A strong budget-oriented conventional RO choice for households that have cabinet space and value certification and standard replacement filters over high output and connected features.
Waterdrop G3P600
A powerful, space-saving RO system for households that want high-capacity filtration and strong contaminant reduction without a storage tank. Best for frequent filtered-water users who can justify the higher upfront and replacement-filter costs.
The Short Answer
Choose the VIVA21 5-Stage for low purchase and maintenance costs; choose the 6-Stage Alkaline version if you specifically want remineralization.
Choose the G3P600 if you want a high-capacity, certified tankless RO system and are comfortable with under-sink installation.
Water Filter Comparison FAQs
Answers are generated from the current SLF product records for these two systems.
Which is better, VIVA21 5-Stage RO or Waterdrop G3P600?
Waterdrop G3P600 is the overall pick for this specific matchup. Choose the G3P600 if you want a high-capacity, certified tankless RO system and are comfortable with under-sink installation.
Which system has the higher daily filtration capacity?
Waterdrop G3P600 has the higher rated output: 600 GPD versus 50 GPD.
Which system offers remineralization?
Both systems are listed as no for remineralization in the current SLF records.
Which system has the lower MSRP?
VIVA21 5-Stage RO has the lower MSRP in the current SLF records at $289.99, compared with $539.00 for the other system.
Do both systems require a plumbing connection?
VIVA21 5-Stage RO: Yes. Waterdrop G3P600: Yes.
Which system is more renter friendly?
VIVA21 5-Stage RO: No. Waterdrop G3P600: No. Check lease and plumbing-modification rules before installing an under-sink system.
What certifications are listed for these systems?
VIVA21 5-Stage RO: Filter United identifies exact model V21RS5S01 as WQA Gold Seal certified to NSF/ANSI 58 for reverse-osmosis system performance and NSF/ANSI/CAN 372 for lead-content compliance. SLF has not independently located the exact model in WQA's searchable public directory, so retain the manufacturer-source qualification until the directory record is captured. Waterdrop G3P600: Exact WD-G3P600 system is documented as IAPMO R&T certified to NSF/ANSI 42, 53 and 58, with NSF/ANSI/CAN 372 for low-lead/material compliance. NSF/ANSI 401 evidence is recorded as third-party tested rather than certified. Exact-model performance data supports verified PFOA/PFOS, chlorine and fluoride reduction.
How do estimated annual filter costs compare?
VIVA21 5-Stage RO: $60.00. Waterdrop G3P600: $144.97. Actual replacement timing and prices can vary.