Key Features

• Disadvantage: Installation and filter replacement require some time and effort. We recommend watching YouTube video 'How to Install iSpring US31 Under Sink Water Filtration System' before purchasing.
• Proven 3-Stage System, Built for PFAS Reduction:The classic 3-stage 2.5" x 10" system—trusted for decades—now upgraded with PFAS-focused filtration media to effectively reduce up to 99% of PFAS (“forever chemicals”), along with chlorine, VOCs, and other contaminants for cleaner, better-tasting water.
• Buy Filter Not Plastic Shell: Reusable housing (pressure hull) lasts 5-10 years—that's why each cartridge uses only 35g of plastic vs. 350g in quick-change twist-on (advantage) cartridges, where the pressure hull with thick walls gets trashed after just one use. What a waste of your money and the environment!
• Physics and Math Never Lie: With reusable housing, each cartridge is nearly full of filtration material: 355g, about 1kg total in 3 stages. That's 7x more filtration material than quick-change filters (only 135g in a single stage).
• Patented Top-Mount Faucet: Installed from above the countertop—just left and twist. No more crawling under the sink.
• What You See Is What's Caught: Clear housing shows captured particles for easy monitoring. We are clear and transparent.
• Tested Where It Matters Most: Not all filters are designed to handle PFAS. The FP15 and FC15 cartridges are NSF/ANSI 58 certified, while the PFAS-targeted filtration media is SGS-tested—built to address “forever chemicals” and deliver cleaner, better-tasting water.
• High capacity with fast flow: up to 10,000 gallons or 12 months of clean water at 5 GPM.
• Healthy Minerals Retained (Does Not Lower TDS): Unlike RO systems, our PFAS/PFOS/PFOA removal filter reduces harmful contaminants while keeping beneficial minerals.
• Lifetime Technical Support: Enjoy a 30-day money-back guarantee, a 1-year limited warranty, and lifetime technical support for ongoing peace of mind and reliable assistance.

Specifications