Sub-Zero · Refrigerator Filters
Sub-Zero Refrigerator Water Filter 4204490
Lower-concern filter type; carbon and resin are standard, but Sub-Zero makes no PFAS disclosure.
Sub-Zero's 4204490 water filter uses activated carbon and ion-exchange resin, established filtration media without known PFAS manufacturing links. However, Sub-Zero provides no public statement on PFAS in this product or its manufacturing. No third-party testing or certification is publicly documented.
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activated 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 4204490 uses activated carbon and ion-exchange resin, the industry-standard media for refrigerator filters. Activated carbon removes chlorine, taste, and odor through adsorption; ion-exchange resin softens water by swapping calcium and magnesium ions for sodium or potassium. Neither material sheds into drinking water under normal use, and both are approved food-contact media by NSF International. The filter housing is typically plastic (polypropylene or similar), which is stable at refrigerator temperatures and does not leach under these conditions.
The brand's record and disclosure
Sub-Zero does not publish detailed water filter material disclosures or third-party certifications (NSF, WQA) on the 4204490 product page. The company has no known safety recalls or controversies tied to this filter line. Sub-Zero's silence on PFAS and other contaminant removal claims is typical for appliance manufacturers but limits transparency compared to specialty filter brands. No independent testing of this specific model against contaminants has been publicly documented.
How it compares in its category
Refrigerator filters are among the simplest water treatment products and carry fewer hazard vectors than faucet-mounted or pitcher filters. The 4204490 is not certified by NSF/ANSI standards, which some competing aftermarket filters carry; this means Sub-Zero does not claim tested reduction rates for specific contaminants. Replacement frequency (every 6 months) is standard. As an OEM filter, it is priced higher than generic third-party carbon filters but integrates seamlessly with Sub-Zero units.
If you buy it
Replace every 6 months or per the refrigerator's change indicator; exhausted carbon loses adsorptive capacity and can support bacterial biofilm growth if left in place. Store unused filters in a cool, dry location away from direct sunlight. Do not attempt to clean or regenerate the filter yourself. Flush the line for 2-3 minutes after installation to clear carbon dust. If water tastes of carbon or smells, replace immediately rather than troubleshooting.
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 in exhausted filter
Activated carbon can harbor bacteria if not replaced on schedule, particularly in warm climates or if refrigerator temperature drifts above 40F. Manufacturer does not provide culture data or antimicrobial treatment for the 4204490.
Plastic housing leaching at temperature extremes
Filter housing is exposed only to cold refrigerator water (typically 35-40F). No evidence of leaching at these temperatures. Risk is negligible unless filter is stored or used in a warm location.
Carbon dust in water post-installation
New activated carbon filters shed fine particles if not flushed before use. Sub-Zero does not specify flushing time; industry best practice is 2-3 minutes. Ingestion of small amounts of carbon dust is not toxic but undesirable.
Ion-exchange resin bead shedding
Resin is retained by the filter cartridge design and does not shed under normal flow. No recalls or complaints on record for the 4204490.
Incomplete contaminant removal without disclosure
Sub-Zero does not publish NSF certifications or tested removal rates for lead, cysts, or PFOA/PFOS. Consumers cannot verify whether the filter reduces specific contaminants relevant to their water quality.
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.