What are the most portable countertop water filter systems for small kitchens or apartments?

A compact countertop reverse osmosis carafe purifier that fills a 64 oz glass carafe; uses a 4-stage filtration system including RO membrane and carbon filters to remove fluoride, PFAS, chlorine and other contaminants. It is plug-in, easy to use, and designed for small households or apartments that need high-quality drinking water without plumbing changes.

Compact 1.5 gallon stainless steel gravity-fed filter that includes two Black Berkey elements and a spigot; produces up to 2.75 gallons per hour and accepts optional PF-2 fluoride/arsenic filters. Portable and durable, made from 304 stainless steel and intended for 1-3 people, travel, RVs, or small kitchens. Suits users needing high contaminant removal without electricity.

A coconut-shell activated CTO carbon block filter cartridge rated for up to 50,000 gallons that removes chlorine, tastes, odors and many organic contaminants. Designed for use as the second-stage filter in 10 in x 4.5 in under-sink or whole-house systems, it offers long life and steady flow for households. Suits users wanting a high-capacity carbon block replacement filter to improve taste and reduce chlorine.

A 6-stage countertop reverse osmosis water dispenser with Aquaporin Inside RO membrane, UV-C LED, compressor cooling and instant heating, a detachable 25-cup raw water tank and 7-cup portable filtered jug, and real-time TDS display. Suits users who want hot and cold purified water on demand without plumbing changes.

The RKIN U1 is a countertop 4-in-1 RO system with 5-stage filtration plus UV and hydrogen infusion, offering instant hot, cold, and room-temperature dispense options and app monitoring. It's third-party tested to reduce TDS, fluoride, lead, PFAS and chromium and is designed for renters or users who want a portable, feature-rich water station without plumbing.