Waterdrop 3US-AF01 Under Sink Water Filter – Replacement for Filtrete 3US-AF01, AP Easy CS-FF, NSF/ANSI 42 – Pack of 3

Waterdrop 3US-AF01 Under Sink Water Filter – a versatile replacement cartridge

Engineered to replace a range of standard under-sink filtration cartridges, this Waterdrop replacement is designed to slot into compatible systems with minimal effort. It carries the updated model designation WD-W01, reflecting recent refinements while preserving familiar performance.

What sets this cartridge apart is its balanced approach to filtration and flow. It pairs a chlorine-reducing filtration media with lead-free materials certified for safe domestic use, so you can enjoy water that tastes cleaner at the tap without worry.

Filtration performance and materials

NSF/ANSI 42 certification marks that the filter targets chlorine-related taste and odor issues. The materials are lead-free and BPA-free, with IAPMO certification under NSF/ANSI 372, supporting confidence in long-term, in-sink use.

• Removes or reduces Chlorine taste and odor
• Protects the water path with lead-free construction
• Fits a range of standard under-sink filtration setups

Flow, TDS and system notes

Tested full-flow performance sits around 0.75 gpm, providing steady water delivery comparable to your home faucet. The cartridge does not reduce total dissolved solids (TDS) and is designed to be connected to the cold-water valve only. Replacement guidance is straightforward: replace every 6 months or 6,000 gallons, whichever comes first, depending on water usage and conditions.

• 6-month or 6,000-gallon replacement cadence to keep taste fresh
• Simple swap with compatible 3US-AS01/CS-FF systems

In daily use, you might notice crisper-tasting tap water and a more inviting aroma when brewing coffee or tea. The compact cartridge is designed to work in tight under-sink spaces, so you can maintain a clean, efficient kitchen setup without sacrificing performance.