WATER FILTER CARTRIDGES

Replacement frequency depends on your water quality, flow rate, and the cartridge type. As a general guideline, replace sediment cartridges in well water applications every 3 to 6 months, or more often if your well has high sediment, iron, or clay content. Carbon cartridges are generally replaced every 6 to 12 months. The most reliable indicator is pressure drop. If you notice reduced flow or pressure at fixtures downstream of the filter, the cartridge is restricting flow and needs replacement. Don't wait for visible discoloration because a cartridge can be fully loaded with fine particles while still appearing clean.

For most residential well water applications, a 5-micron cartridge handles fine sediment effectively and is the most common rating for whole house well filtration. If your well has heavier sand or particulate issues, start with a 20- or 30-micron cartridge to capture bulk sediment and extend the life of a finer downstream stage. If you're running a UV system for disinfection, the UV manufacturer will specify a pre-filter micron rating (typically 5 microns or finer) to ensure particles don't shield bacteria from the UV light. Check your UV bulb system's requirements before selecting a cartridge for that application.

Both types filter sediment, but they do it differently and have different service characteristics. Polypropylene string wound and dual gradient cartridges use depth filtration where particles are captured throughout the thickness of the wound media. They're generally less expensive per cartridge but are single-use and need to be replaced when spent. Pleated cartridges use a folded media that provides more surface area in the same footprint, resulting in lower pressure drop and longer service life. Polyester pleated models are also washable and reusable, which reduces long-term cost in lower-sediment applications. For high-sediment well water, polypropylene dual gradient cartridges typically hold more dirt before restriction becomes an issue. For clean water with occasional fine particles, pleated cartridges last longer between changes.

A dual gradient cartridge, such as the Pentair Pentek DGD Series, is wound with two different micron densities in a single cartridge. The cartridge includes a looser outer layer that captures large particles first, along with a tighter inner core that removes fine sediment as water moves toward the center. This graded construction prevents the outer surface from loading quickly with finer particles by allowing them to pass through to the inner core.The result is higher total dirt-holding capacity and a longer effective service life compared to a single-micron cartridge of the same size. The DGD-5005 (50/5 micron) and DGD-2501 (25/1 micron) are available in both 4"x10" and 4"x20" sizes.

No, cartridges are sized to specific housing dimensions. For example, a 4"x10" cartridge fits a 4"x10" (Big Blue 10") housing, and a 4"x20" cartridge fits a 4"x20" (Big Blue 20") housing. The nominal diameter must match your housing's sump interior. Most Big Blue-style housings from Pentair and compatible manufacturers accept standard 4.5"-diameter cartridges. If you're unsure of your housing model, measure the length and diameter of your current cartridge before ordering. If you need help confirming compatibility, call us at 1-800-252-6665.

Well water doesn't typically contain chlorine, so a granular activated carbon cartridge, which is primarily designed to reduce chlorine and associated taste/odor compounds, is less commonly needed for private well applications than for municipal water. If your well water has a sulfur or organic odor, a carbon cartridge may help, but the source of the odor should be identified first because carbon filtration treats a symptom, not the underlying water quality issue. For well water, sediment filtration is the baseline requirement and carbon filtration is additive based on your specific water test results.

A spin-down filter is a reusable in-line pre-filter installed upstream of your main cartridge housing. It uses centrifugal force to spin sand, grit, and coarse sediment out of the water stream before it reaches your primary cartridge. Because it captures large particles that would otherwise load your cartridge quickly, a spin-down pre-filter significantly extends the life of your downstream cartridges in wells with sand or high particulate output. The Campbell spin-down unit in this collection includes a flush valve that lets you drain collected sediment without removing the filter from the line. To start, check the clear bowl periodically to monitor what your well is producing.

The clearest signal is a drop in water pressure or flow rate at fixtures downstream of the filter. A pressure gauge installed before and after the filter housing makes this easy to monitor. For reference, a differential of 10 PSI or more typically indicates a cartridge that needs replacement. If you don't have gauges, a noticeable reduction in shower pressure or faucet flow is a reliable practical indicator. Some homeowners replace cartridges on a fixed schedule (every 3, 6, or 12 months depending on water quality) to avoid service disruption. For high-sediment wells, scheduled replacement is more predictable than monitoring by feel.