S'well Original Bottle
Low risk. S'well does not reveal PFAS use in insulation.
S'well bottles combine stainless steel with a proprietary foam insulation layer. The brand has not revealed whether the insulation includes water-repellent or stain-resistance treatments. No third-party PFAS testing is publicly known.
We flunk more products than we pass. This one earned its grade. How we grade
Material
stainless steel with proprietary insulation layer
Lab data
No public lab test
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What S'well Original Bottle is made of, ingredients and materials
S'well Original Bottles are constructed from 18/8 stainless steel (austenitic grade, chromium-nickel alloy) with a proprietary polyurethane or foam insulation layer sandwiched between the outer and inner walls. Stainless steel of this grade is inherently corrosion-resistant and does not leach nickel, chromium, or other metals into cold or room-temperature beverages under normal use. The insulation layer composition is not disclosed publicly, which is the primary point of uncertainty for this product category.
What’s concerning
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Insulation layer chemical composition (unknown)
The proprietary insulation material is not disclosed; it may contain polyurethane, polyethylene foam, or other polymers with potential additives (flame retardants, blowing agents). Without public disclosure or testing, the presence of PFAS, volatile organic compounds, or other chemicals cannot be ruled out.
Seal degradation and microbial growth
If the double-wall seal fails (due to impact or thermal cycling), moisture can accumulate in the insulation cavity, creating conditions for bacterial or mold growth. This is a maintenance issue rather than a material hazard but requires user vigilance.
Off-gassing from insulation during manufacture or storage
Foam insulation materials may release volatile organic compounds during production or initial use, particularly if the bottle is sealed and heated. No testing data or consumer complaints are on record, but this is a theoretical risk for any foam-insulated product with undisclosed composition.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Nickel leaching from stainless steel
18/8 stainless steel does not leach nickel into cold or neutral-pH beverages under normal conditions. No recalls or complaints of metal contamination have been reported for S'well bottles.
Coating or enamel degradation
S'well bottles are bare stainless steel with no applied coating or enamel; the exterior is stainless steel and the interior is also stainless steel. There is no glaze or ceramic layer to degrade.
How is this PFAS grade calculated?
The brand's record and disclosure
S'well does not publish detailed material safety data sheets, third-party certifications (e.g., NSF, FDA material compliance letters), or statements regarding PFAS or other chemical additives in the insulation layer. The brand has faced no documented recalls related to leaching, coating failure, or contamination. S'well's marketing emphasizes durability and temperature retention but does not address material transparency, a notable gap compared to competitors who voluntarily disclose insulation composition or pursue safety certifications.
How it compares in its category
S'well bottles are premium priced and do not fall into the water-filter category; they are insulated beverage containers. Compared to plastic water bottles (which risk BPA or phthalate leaching), stainless steel is chemically inert for the container itself. However, unlike some competitors (e.g., Hydro Flask, Klean Kanteen), S'well does not publicly disclose insulation safety data, making direct hazard comparison difficult. For true water filtration, this product does not filter; it only stores.
If you buy it
Hand wash rather than dishwasher to minimize thermal stress on the insulation seal; avoid prolonged exposure to temperatures above 60 C (140 F) to preserve the integrity of the foam layer. The bottle is designed for long-term use; no replacement interval is necessary unless visible damage (dents, seal separation, or condensation inside the double wall) occurs. Do not microwave. Store dry to prevent mold growth in the insulation cavity if moisture enters through a compromised seal.
What is not known about PFAS in this product?
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- S'well has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
What are the PFAS-free alternatives to S'well Original Bottle?
- glass bottles, sodium dichloroisocyanurate treatment chemical
- We found no PFAS statement from the brand
- Chemical overdose or misuse
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- Stainless steel housing and spigot
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- Bacterial growth and biofilm if filters not replaced
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- Borosilicate glass pitcher, replaceable activated-carbon filter cartridge
- Bacterial growth in filter cartridge if unmaintained
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More water 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.