Product Price Filter Capacity (gallons) Flow Rate (GPM (Gallons Per Minute)) Contaminant Removal Installation Difficulty Warranty (years) Water Pressure Requirement (PSI (Pounds per Square Inch))
Clearly Filtered 3-Stage Under Sink System
US
£369.87 2000 gallons 1.08 GPM 232+ contaminants 100% DIY Limited lifetime Standard residential (~60 psi)

A compact 3-stage under-sink filter using Affinity® filtration to remove 232+ contaminants while retaining beneficial minerals. Suited for homeowners or renters wanting high contaminant protection with DIY installation and annual filter changes.

Waterdrop X12-PRO 11-Stage Tankless RO
US
£939.72 24 months for RO filter (X12-F3); 12 months F1A; 6 months F2-PRO 1200 GPD Reduces TDS, PFOA, PFOS, chlorine, fluoride, arsenic, lead, barium, chromium-VI, microplastics, odors Involved; may require professional plumber for typical install (about 2 hours) 2 years

Tankless under-sink RO with 11-stage filtration and an alkaline remineralization stage. Delivers high-speed 1200 GPD output, dual-flow (purified and filtered) lines, smart faucet with TDS and filter-life display; suited for families or light commercial use needing high throughput.

iSpring RCC7AK 6-Stage Reverse Osmosis
US
£180.82 75 GPD Removes up to 99% of 1000+ contaminants; TDS 97.9%; Lead 98.9%; Fluoride 97.4%; PFAS (includes PFOA and PFOS) reduced DIY installation with basic plumbing knowledge; push-fit quick connectors; online videos and lifetime tech support 1-year limited manufacturer warranty (registration required)

The iSpring RCC7AK is a 6-stage under-sink RO system (includes alkaline remineralization) certified to NSF/ANSI 58 that produces up to 75 gallons per day and restores healthy minerals for better taste. It suits homeowners wanting high contaminant removal and bottled-water taste with a do-it-yourself install.

Frizzlife Frizzlife MK99 Under Sink Water Filter
US
£44.82 1600 gal 2 GPM @ 60 psi lead chlorine taste odor particulates tool-free, 3 minute setup 1 year (register for extended) 20 psi min 80 psi max

Two-stage under-sink system with a 0.5 micron cartridge offering high flow and tool-free, quick-change installation; certified to NSF/ANSI 42/53 for common contaminants and suited for households wanting fast, filtered drinking water without complex plumbing. Replacement cartridges are inexpensive and the unit fits 3/8 and 1/2 cold water lines.

Waterdrop Waterdrop 15UA Inline Under-Sink Filter
US
£46.32 16000 gallons 0.75 GPM PFAS PFOA PFOS lead chlorine heavy metals chemicals sediment taste and odor Easy push-to-connect, install in minutes 24 months 10-125 psi

Multistage inline under-sink filter certified to NSF/ANSI 42 and 53 that delivers up to 16,000 gallons with a 0.75 GPM flow rate. It reduces PFAS, lead, chlorine, heavy metals and improves taste; suited for households wanting a simple, fast-install filtration without a separate faucet.

Aquasana Aquasana OptimH2O Under Sink Reverse Osmosis + Claryum (3-stage)
US
£142.89 265 gallons 0.5 gpm Removes up to 99.99% of 78 contaminants including chlorine PFAS lead fluoride arsenic Easy to install with step-by-step guides and videos; no plumber required for filter replacements Limited Warranty (details on product page) Not specified

High-efficiency under-sink RO + Claryum system combining RO membrane, carbon and Claryum filtration with a remineralizer for better taste. Suited for households wanting broad contaminant removal (including fluoride and arsenic) with retained beneficial minerals.

APEC APEC ROES-50 Essence Series 5-Stage Reverse Osmosis System
US
£149.40 large capacity block filters (no liters specified) 50 gallons per day @ 60 psi removes up to 99% of contaminants including chlorine, lead, fluoride, arsenic, chromium, heavy metals, bacteria, virus easy DIY with provided hardware and instructions 2 year extended manufacturer warranty with registration 40-85 psi

Five-stage under-sink RO system delivering up to 50 gallons per day, WQA Gold Seal certified, includes 4 gallon tank and designer faucet. Suits households wanting high contaminant removal and DIY installation at an affordable price.

APEC Water Systems APEC ROES-50 Essence Series 5-stage Reverse Osmosis System
US
£172.60 4 gallons tank 50 gallons per day @ 60 psi Removes up to 99% of contaminants including chlorine, lead, fluoride, arsenic, chromium Easy DIY with provided hardware and instructions 2 year with registration 40-85 psi

Five-stage under-sink RO that produces up to 50 gallons/day, includes designer faucet and 4 gallon tank. Suited for households wanting high contaminant removal and DIY installation at home.

APEC Water Systems ROES-50 Essence Series
US
£172.60 50 gallons per day @ 60 psi, 30 gallons per day @ 50 psi 50 GPD Removes up to 99% of contaminants including chlorine, lead, fluoride, arsenic, PFAS, VOCs, bacteria, viruses Easy do-it-yourself installation with quick connection fittings and color coded tubing 2 year with registration 40-85 psi

The APEC ROES-50 Essence Series is a 5-stage under-sink reverse osmosis system that produces up to 50 gallons per day and removes up to 99% of common contaminants. It includes a 4 gallon tank and a designer faucet and suits households wanting high contaminant removal and a DIY-friendly install.

Waterdrop Waterdrop G3P600 8-stage Reverse Osmosis System
US
£320.55 2200 gallons RO filter; 6 months CF; 12 months CB 600 GPD Reduces TDS, PFAS, fluoride, arsenic, lead, chlorine and more (NSF/ANSI 42, 58, 372) DIY install in about 30 minutes (requires under-sink power) 1 year

Tankless 8-stage RO delivering up to 600 gallons per day with a 2:1 pure-to-drain ratio, NSF certifications, built-in TDS monitor and smart faucet. Suits households wanting high-capacity, space-saving, high-performance RO filtration and willing to use an under-sink powered unit.

Waterdrop G3P600 (8-Stage)
US
£320.55 600 GPD 600 GPD TDS, PFOA, PFOS, Fluoride, Chlorine, Arsenic, Lead, Chromium-6, PFAS DIY install, about 30 minutes 1 Year

The Waterdrop G3P600 is a tankless under-sink reverse osmosis system with 8-stage filtration and a 0.0001μm RO membrane that delivers fast on-demand purified water (about 8 seconds per cup). It suits households wanting high-capacity RO performance in a compact, tankless design and who are comfortable with a DIY under-sink installation.

Clearly Filtered Clearly Filtered 3-Stage Under Sink System
US
£369.87 2000 gallons 1.08 GPM 232+ contaminants 100% DIY Limited lifetime warranty ~60 psi

Three-stage under-sink system using Affinity filtration to target over 232 contaminants while retaining beneficial minerals. Filters last about one year (≈2000 gallons) and suit homeowners or renters wanting high contaminant removal without a separate faucet.

Cloud Water Cloud RO Under-Sink Reverse Osmosis System
US
£447.57 80 GPD membrane; tank 2.8 gallons 0.625 GPM faucet flow Removes PFAS, lead, fluoride, VOCs, disinfectant byproducts, heavy metals; 98% TDS rejection 30 minute install; DIY-friendly but requires basic plumbing (faucet hole and drain hookup) 10 year system life stated (no specific warranty period found) Outlet pressure 40-45 psi

Cloud RO is a compact under-sink RO system with a built-in pump, remineralization stage, app monitoring, and a 1:1 waste ratio. It suits households wanting high contaminant removal with faster refill times and app-based maintenance reminders.

Cloud RO Cloud RO Under-Sink Reverse Osmosis System (tank-based)
US
£447.57 3.2 gallons (tank) 80 GPD TDS, THMs, lead, fluoride, copper, barium, VOCs, pesticides, pharmaceuticals, PFAS (varies by test) Requires basic DIY plumbing; 30-60 minutes for typical install null null

Cloud RO is a 4-stage under-sink reverse osmosis system with a 3.2 gallon tank, built-in remineralization, battery-powered pump, app monitoring, and NSF/ANSI 58 certification for TDS reduction. It suits households wanting high contaminant reduction with smart monitoring and those comfortable with under-sink installation.

Waterdrop Waterdrop G3P800 Tankless Under Sink Reverse Osmosis System
US
£502.61 2200 gallons 800 GPD Removes PFAS fluoride lead chromium heavy metals chlorine TDS (NSF/ANSI certified) DIY under-sink, approximately 30-60 minutes 1 year 60 PSI

Tankless under-sink RO that produces up to 800 GPD with a smart TDS-display faucet, UV sterilization, and multi-stage filtration removing PFAS and many regulated contaminants. Suits households that want high-flow, tankless RO performance and space savings with DIY installation.

Cloud RO Cloud RO Tankless Under-Sink Reverse Osmosis System (compact model)
US
£560.40 3.2 gallons 0.05 GPM TDS reduction; removes up to 99% of contaminants (manufacturer claims) Requires DIY plumbing knowledge; moderate difficulty 50 PSI (tested at 50 PSI)

Compact tank-and-unit design fits under most sinks, includes remineralizer and battery-backed pump, and produces high-purity water with about 1:1 waste ratio. Suited for small households wanting compact RO performance and app monitoring.