Culligan · Refrigerator Filters
Culligan CUW4 Refrigerator Water Filter
Lower PFAS concern; standard carbon/resin filters are not known PFAS sources, but Culligan makes no public PFAS disclosure.
The CUW4 uses activated carbon and ion-exchange resin, typical filter materials with lower inherent PFAS risk compared to Teflon-family coating coatings. Culligan has not publicly disclosed PFAS testing or claims. No third-party verification is available.
Shop Culligan on Amazon →Material
Carbon and ion-exchange resin filter media
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
No PFAS disclosure
No public statement about PFAS in this product.
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
The full breakdown
What it's made of and why it matters
The CUW4 uses activated carbon and ion-exchange resin to remove chlorine, sediment, and some dissolved minerals from refrigerator water dispensers. Activated carbon is inert once installed and does not leach harmful chemicals into water under normal use. Ion-exchange resin beads are food-contact approved materials that soften water by exchanging sodium or potassium ions; they remain stable inside the filter cartridge and do not migrate into drinking water when functioning correctly.
The brand's record and disclosure
Culligan is a long-established water treatment company with NSF/ANSI certification for many of its products, indicating third-party validation of contaminant reduction claims. The company makes no public disclosure of PFAS testing or removal capacity for the CUW4 specifically, which is typical for basic refrigerator filters in this product class. No major safety recalls or contamination incidents are on record for this model. Culligan's silence on PFAS does not indicate a problem, but reflects the absence of marketing claims around PFAS removal.
How it compares in its category
Refrigerator filters like the CUW4 are among the simplest water treatment devices and carry fewer hazard pathways than pitcher filters, under-sink systems, or reverse osmosis units. Most direct competitors (Maytag UKF8001, Whirlpool EDR3RXD) use nearly identical carbon-resin technology with similar safety profiles. The CUW4 does not claim to reduce PFAS, and neither do most standard refrigerator filters; activated carbon alone has limited PFAS removal unless specifically engineered with resins designed for that purpose.
If you buy it
Replace the filter every 6 months or 300-500 gallons, whichever comes first, to prevent bacterial biofilm buildup inside the cartridge and maintain flow rate. Do not attempt to clean or reuse the filter; it is a single-use disposable cartridge. Ensure the filter is seated fully in the refrigerator housing to avoid bypass leaks. Store unused filters in a cool, dry place and discard if the cartridge shows visible mold, discoloration, or has been exposed to temperatures above 70 degrees Celsius for extended periods.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Bacterial growth from expired or unmaintained filter
If a CUW4 is not replaced on schedule, stagnant water inside the saturated carbon matrix can support microbial colonies. This is a maintenance issue, not a manufacturing defect, and is prevented by timely replacement.
Carbon dust or resin particle release during initial use
Properly manufactured filters are pre-rinsed to flush loose fines, and the CUW4 has no documented cases of visible particle shedding. If particles appear in water, the filter may be damaged or installed incorrectly.
Ion-exchange resin leaching
Resin beads are encased inside the filter cartridge and remain inert under normal cold-water refrigerator conditions. No evidence of resin migration into water has been documented for this product class.
Chlorine byproduct breakthrough after saturation
If the CUW4 is used beyond its rated capacity, the carbon becomes saturated and stops adsorbing chlorine and some volatile organics. This is a loss of filtering efficacy rather than a toxicity hazard, but indicates need for timely replacement.
Housing or seal leachables from plastic refrigerator connection
The filter cartridge itself contains no plastics in direct contact with water; the plastic housing is part of the refrigerator unit. No specific leachate issues are on record for the CUW4 filter media.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 72% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Refrigerator Filters
Kenmore
9690 Refrigerator Water Filter 1-Pack, Nsf/wqa/iapmo Certified, Reduces 99% Chlorine & Odor, BPA-Free, Replacement for 46-9690 469690 Lt700p
activated carbon filter cartridge
Lower-concern water filter; carbon-based design unlikely to contain PFAS, but Kenmore makes no explicit PFAS disclosure.
✓Verified PFAS-free by a third party
Kenmore
Pureline Filter Compatible with Whirlpool Everydrop Filter 1
Activated carbon and fiberglass filter media
Lower concern for PFAS; standard cartridge filter with no known PFAS-bearing materials, but brand offers no transparency.
✓Bare metal or glass, no coating at all
Clearly Filtered
Water Pitcher Replacement Filter 3-Pack
Activated carbon and ion-exchange resin filter media
Lower-concern option; activated carbon filters are standard PFAS-reduction media, but verify pitcher durability and actual tested removal rates independently.
✓Brand claims PFAS-free (unverified)
More refrigerator filters grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.