EWS RO4 & RO4-UV – Four-Stage Under Sink Reverse Osmosis Drinking Water Systems
The EWS RO4 is a high-performance reverse osmosis system that delivers pure, safe, and great-tasting water right at your tap. Featuring four advanced stages of filtration, the RO4 removes or reduces chlorine, lead, fluoride, arsenic, nitrates, PFAS, and more. For added protection, the RO4-UV variant includes an integrated UV disinfection stage, safeguarding your family against bacteria, viruses, and other microorganisms.
Why Choose the EWS RO4 or RO4-UV?
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Complete 4-Stage Filtration — sediment pre-filter, advanced carbon pre-filter, RO membrane, and carbon block post-filter ensure maximum contaminant reduction.
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UV Protection (RO4-UV) — adds an ultraviolet disinfection lamp that kills 99.99% of bacteria, viruses, and cysts for total peace of mind.
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Removes a Broad Range of Contaminants — chlorine, chloramine, nitrates, lead, arsenic, fluoride, heavy metals, PFAS, VOCs, THMs, and more.
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Compact Design — just 5" D × 16" L × 16" W, fits neatly under most sinks.
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High Purification Efficiency — delivers up to 50 gallons per day (GPD) of purified water.
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Safe & Compliant — all components are food- and beverage-grade; meets California No-Lead Standards.
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Easy Maintenance — filters and membrane are replaced annually with F.SET.RO4 or F.SET.RO4-UV.
- City or Well Water
Filtration Stages
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Stage 1 – F.INLINE (5 Micron Pre-Sediment): Removes dirt, rust, and silt to protect downstream filters.
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Stage 2 – F-GAC (Advanced Carbon): Reduces chlorine, chloramine, VOCs, THMs, PFAS, and improves taste/odor.
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Stage 3 – F-MEM (RO Membrane): Strips water of fluoride, arsenic, nitrates, lead, heavy metals, and dissolved solids.
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Stage 4 – F-GAC-B (Carbon Block Polishing): Improves taste, odor, and clarity before water reaches your faucet.
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Optional Stage 5 – F-LAMP (UV Disinfection, RO4-UV only): Ultraviolet light inactivates bacteria, viruses, and microorganisms for added protection.
Technical Specifications
| Model # |
RO4 (standard) / RO4-UV (with UV protection) |
| System Flow Rate |
<10 GPM (typical output up to 50 GPD) |
| Operating Pressure |
40–75 psi |
| Operating Temperature |
40°F – 100°F (4°C – 38°C) |
| Dimensions |
5″ D × 16″ L × 16″ W (allow 4″ clearance for filter changes) |
| Shipping Weight |
≈18 lbs |
| Replacement Filter Sets |
F.SET.RO4 (standard) / F.SET.RO4-UV (with UV lamp) |
| Service Life |
Replace filters, membrane, and UV lamp annually (do not exceed 1 year) |
*Performance and filter life may vary depending on water quality and usage.
What’s Included
- RO4 or RO4-UV system with 4-stage (or 5-stage with UV) filtration
- Storage tank (3.2 gallon capacity, other sizes available)
- Dedicated faucet/dispenser (finish options available)
- Color-coded tubing and fittings for installation
- Instruction and installation manual
Applications
- Residential kitchens and wet bars
- Homes seeking removal of heavy metals, fluoride, nitrates, PFAS, and other contaminants
- RO4-UV: ideal for added disinfection against bacteria and viruses
- Perfect for households seeking pure, safe drinking and cooking water directly at the tap
*WELL WATER WARNING Well water is required to have independent, complete and proper testing of your well water to determine the proper course of action in order to specify the correct system(s).
Water Hardness Caution: Physical conditioning can have a limited effectiveness with water hardness up to 500mg/l or 30 grains and greater. Similar to issues with softeners and ion-exchange, conditioning can be adversely effected by abnormal levels of pH, alkalinity, and/or silica. Please consult with your sales associate or EWS, Inc. to establish proper aesthetic expectations, helpful household hints, or a combination of product and your best alternatives.
Model # F.SET.RO4 / F.SET.RO4-UV
Includes
F.SET.RO4: F-INLINE, F-GAC, F-MEM, F-GAC-B
F.SET.RO4-UV: F-INLINE, F-GAC, F-MEM, F-GAC-B, F-LAMP
Replace filters annually or as needed for reliable performance
