20 x 4.5 Inch Replacement Filters
The 20 x 4.5 inch Big Blue cartridge is the standard for high-flow whole house filtration — and this is our complete catalog for the size, with 78+ options across every major filter media type.
If you already know what media you need, our dedicated sub-collections will get you there faster:
- 20 x 4.5" Sediment Filters — spun polypropylene and dual-gradient cartridges (Pentek DGD-5005, DGD-2501) for dirt, rust, and sand removal
- 20 x 4.5" Carbon Filters — GAC and carbon block cartridges for chlorine, chloramine, PFAS, and taste/odor reduction
- 20 x 4.5" Pleated Filters — pleated polypropylene cartridges for higher dirt-holding capacity and longer service life
All cartridges listed here fit standard 20 x 4.5 inch Big Blue housings. If you need a housing rather than a replacement cartridge, visit our Water Filter Housings collection. Can't find what you need? Call 1-800-277-3458.
