Clearly Filtered · Water Filters
40oz Insulated Stainless Steel Filtered Water Bottle
Lower PFAS concern for the steel body; filter cartridge needs brand clarification.
The 40oz stainless steel insulated bottle itself poses lower PFAS risk because stainless steel is a stable, non-coated material. However, the filtered water bottle's cartridge composition is not publicly documented by Clearly Filtered, and no PFAS claims or third-party testing data are available.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel body; carbon/activated carbon filter cartridge
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What 40oz Insulated Stainless Steel Filtered is made of, ingredients and materials
The 40oz body is 18/8 stainless steel, which is highly resistant to corrosion and does not leach heavy metals or BPA under normal use. The filter cartridge uses activated carbon, a porous form of carbon that adsorbs contaminants; this material itself is inert when food-grade. The critical unknown is what binder, resin, or structural material holds the carbon particles together inside the cartridge, manufacturers rarely disclose this, and some use phenolic resins or epoxy that could theoretically release trace compounds if saturated or heated.
What’s concerning
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Filter cartridge binder/resin leaching
Activated carbon cartridges often use phenolic resin, epoxy, or melamine-formaldehyde as structural binders; manufacturer does not publicly specify which. If cartridge is oversaturated or subjected to temperature stress, trace leaching is theoretically possible but has not been reported for this brand.
Bacterial colonization in filter
Activated carbon filters can harbor bacterial growth if not replaced regularly or if bottle sits unused for weeks. This is a maintenance risk, not a design defect, but applies to all carbon-filter bottles in this category.
What’s reassuring
Bare uncoated material
Recorded as a bare, uncoated material with no surface coating or treatment.
Cap/seal material off-gassing
Most 40oz bottles use polypropylene (PP) or silicone caps and seals. Clearly Filtered does not disclose cap material publicly; no safety issues are documented for this model, but cold-resistant silicone is preferable to PP if long-term leaching is a concern.
Heavy metals
Activated carbon alone does not remove all heavy metals (e.g., lead, cadmium) without ion-exchange resin or other media. If source water is contaminated, this filter may not reduce metals sufficiently; brand claims should be verified against your local water test.
Source, FDA ↗Stainless steel corrosion and pitting
18/8 stainless steel is highly resistant to corrosion. Pitting from chloride attack is extremely rare in fresh water but could theoretically occur in high-salt environments or if bottle is never rinsed; this is not a documented issue for this product.
The full breakdown
The brand's record and disclosure
Clearly Filtered markets itself as PFAS-focused but provides minimal public disclosure on cartridge construction, manufacturing standards, or third-party testing of the filter housing itself. No major recalls or safety incidents are on record for this product line. The brand does not appear to hold NSF or WQA certification for the filter cartridge, which would provide independent verification of contaminant removal claims and material safety.
How it compares in its category
Filtered water bottles in this size range typically use either activated carbon (as here) or ion-exchange resin cartridges. Clearly Filtered's stainless steel body presents lower concern than plastic-bodied competitors, which carry BPA/microplastic risk if degraded. However, competitors like Berkey or ZeroWater publish more detailed filter specifications and independent test reports; Clearly Filtered lags in transparency for the cartridge itself.
If you buy it
Replace the filter cartridge every 2-3 months or per manufacturer guidance to prevent bacterial growth and saturation-induced leaching. Do not expose the cap or cartridge housing to heat above 140F, as this can stress seal materials and resins. Store filled bottles at room temperature away from direct sunlight; freezing may stress seals over time. Rinse the cartridge under cold water before first use to remove carbon dust.
What we don’t know
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Clearly Filtered has made none
Formulations change between production runs, so check the current label. How we grade.
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