The USWF 25 Micron 20x4.5 String Wound Sediment Filter has a 25-micron rating, making it ideal for capturing larger sediment particles such as sand, silt, rust, dirt, and scale from your water supply. Its tightly wound polypropylene cord construction creates a true depth-gradient filtration pattern, trapping contaminants throughout the entire filter body rather than just on the surface. This makes it an excellent choice as a pre-filter for whole-house systems, well water applications, and protecting downstream RO membranes or carbon filters from premature clogging.

This USWF string wound sediment filter measures 20 inches in length and 4.5 inches in diameter (20" x 4.5"), commonly referred to as a "Big Blue" size. It is designed to fit standard 20" x 4.5" Big Blue-style whole-house filter housings, including popular models from Pentek, Pentair, American Plumber, and other compatible 20-inch heavy-duty housings. Always verify your existing housing accepts a 20x4.5 cartridge before purchasing.

The typical service life of this USWF string wound sediment filter is 3 to 6 months, depending on your incoming water quality, sediment load, and daily usage volume. Homes on well water or with heavy sediment may require more frequent replacement, while municipal water users often achieve the full 6-month lifespan. Monitor for reduced water pressure or visible discoloration of the cord as signs it's time to replace the cartridge.

Yes, the USWF 25 Micron 20x4.5 String Wound Sediment Filter is manufactured from 100% FDA-compliant food-grade polypropylene cord wound around a durable polypropylene core. It contains no binders, adhesives, or surfactants that could leach into your water. The all-polypropylene construction is compatible with a wide pH range (1–13) and suitable for both hot and cold water applications up to 145°F, making it versatile for residential, commercial, and light industrial use.

String wound filters like this USWF 25 micron cartridge offer superior dirt-holding capacity compared to spun polypropylene filters of the same size, thanks to their gradient-density winding pattern that captures larger particles on the outside and finer particles toward the core. Unlike pleated filters, they are not reusable, but they excel at handling high sediment loads without rapid pressure drop. This makes the USWF 20x4.5 string wound filter the preferred choice for well water, agricultural, and heavy-sediment pre-filtration applications where maximum particulate capture is essential.