Filter United · VIVA21 collection
Enjoy crisp, refreshing water straight from your kitchen. Filter United reverse osmosis water filter systems combine multi-stage filtration, WQA Gold Seal certification, and lifetime product support for everyday drinking and cooking.
Multi-stage filtration. Dedicated drinking-water faucet. Lifetime product support.
Filter United RO systems
Explore under-sink RO systems for drinking-water treatment. View each model’s filtration stages, operating requirements, and included components.
Five-stage under-sink reverse osmosis water filter with sediment and carbon prefiltration, an RO membrane, and post-carbon filtration. Faucet and storage tank included.
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Six-stage under-sink reverse osmosis water filter with post-RO alkaline remineralization. Combines membrane filtration and mineral media; faucet and storage tank included.
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A reverse osmosis water filter uses pressure to separate water across a semipermeable membrane, reducing total dissolved solids (TDS). Under-sink RO systems combine membrane treatment with sediment and carbon filtration to supply treated water at a dedicated faucet.
The Filter United approach
Evaluate the system behind the specification: certification scope, replacement-filter availability, and support after installation.
VIVA21’s WQA Gold Seal certification adds independent evaluation to your buying decision. Testing to recognized standards helps verify certified performance, material safety, and structural integrity; specific reduction claims depend on the model’s listing.
Replacement sediment filters, carbon filters, RO membranes, and post-filters are available. Select parts matched to your system and maintenance schedule.
VIVA21 includes lifetime support for installation and maintenance. Product pages specify package contents, operating limits, and applicable warranty terms.
Multi-stage water treatment
Prefiltration, membrane separation, and post-filtration perform different treatment functions. The RO membrane is the stage that reduces dissolved salts.
A sediment filter traps suspended particles. Carbon prefilters reduce chlorine and help protect the downstream membrane from chlorine exposure.
Applied pressure produces treated water, called permeate, and a concentrate stream carrying rejected dissolved substances to the drain.
Post-carbon filtration polishes taste before dispensing. Models with a remineralization stage add mineral media after membrane treatment.
TDS reduction: Total dissolved solids describe dissolved substances such as mineral salts. Membrane rejection and individual contaminant-reduction claims are different measurements; a TDS reading alone does not identify which contaminants are present.
Production rate: A gallons-per-day (GPD) rating describes output under specified test conditions, not the faucet’s instantaneous flow. Feed-water pressure, temperature, and dissolved-salt concentration affect membrane performance.
Concentrate water: RO separates feed water into permeate and concentrate. Check the specific system’s recovery or efficiency rating to understand water use; those ratings should not be assumed from the number of filter stages.
System components
VIVA21 combines replaceable filter housings and membrane treatment beneath the sink, supplying a dedicated faucet through a storage tank. Check each listing for dimensions and included components.
Installation requirements
An under-sink reverse osmosis water filter requires a compatible cold-water connection, a drain connection, and a dedicated faucet location.
Follow the model’s installation, flushing, and sanitizing instructions. Use a qualified installer for unfamiliar connections or drilling.
Filtration resources
Go deeper into certification, installation, and water quality.
Identify standards and model-specific reduction claims.
Read the guide InstallationReview system connections before installation.
View installation guide Water educationExplore source water, filtration, and maintenance.
Explore the knowledge libraryTechnical questions, answered
Explore contaminant reduction, output, maintenance, and installation.
Filter United VIVA21 systems combine sediment filtration, carbon filtration, and a reverse osmosis membrane to address suspended particles, chlorine taste and odor, and dissolved solids. This multi-stage approach brings drinking-water treatment to your kitchen faucet. For specific concerns such as lead or fluoride, our team can help you review the exact model’s certified reduction claims before you choose.
VIVA21 uses both technologies because they do different jobs. Carbon prefilters reduce chlorine and help protect the membrane. The RO membrane reduces dissolved salts through pressure-driven separation, while post-carbon filtration polishes the water’s taste before dispensing. Together, these stages support a complete under-sink drinking-water system.
Feed-water pressure, temperature, dissolved-salt concentration, and storage-tank pressure influence RO production. Filter United lists the rated capacity and operating requirements on each VIVA21 product page, so you can check the fit for your home before buying. A gallons-per-day rating describes production under stated conditions, rather than the faucet’s instantaneous flow. Contact us if you need help reviewing your setup.
VIVA21 treats water at its dedicated drinking-water faucet, making it a practical option for drinking and cooking without installing a whole-house RO system. A compatible connection kit may also supply a refrigerator or ice maker, subject to connection and pressure requirements. Our team can help you review the accessories needed for your installation.
Yes. Reverse osmosis reduces many dissolved minerals along with other dissolved substances. For shoppers who prefer remineralized water, Filter United offers a VIVA21 system with an additional post-RO alkaline remineralization stage. This stage can change mineral content and taste. Final pH varies with the water and operating conditions; a fixed pH or additional health benefit is not promised.
It adds independent evaluation behind your purchase. VIVA21 product listings identify WQA Gold Seal certification to NSF/ANSI 58 and NSF/ANSI/CAN 372. NSF/ANSI 58 addresses RO system requirements, including TDS reduction; NSF/ANSI/CAN 372 addresses material lead content. Check the model’s listing for its specific certified reductions. Certification to an NSF standard by WQA is distinct from certification by NSF itself.
Follow the maintenance schedule for your VIVA21 model and each installed filter stage. Source-water quality and household water use affect replacement needs. Filter United offers matching sediment filters, carbon filters, RO membranes, and complete replacement sets, with lifetime product support to help identify the right parts. Shop VIVA21 replacement filters.
VIVA21 is designed for under-sink installation, and Filter United provides an installation guide and lifetime product support to help you through the process. Review the required cabinet space, cold-water connection, drain connection, and faucet opening before starting. Use a qualified installer for unfamiliar plumbing or drilling, then flush the system and inspect every connection as directed in the manual.
A well-water test is the best starting point. Well water can contain sediment, hardness, iron, or microorganisms that call for pretreatment or disinfection before an RO system. Share your results with Filter United so we can help you review VIVA21’s source-water requirements. The system should not be treated as a disinfectant for microbiologically unsafe water.
Filter United · VIVA21
Explore system specifications, filtration stages, and current availability.
