By PFAS Authority · Updated August 27, 2026
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Model-based grades, not lab tests. We flunk more than we pass. How grading works
PFAS in Waterproof Boots, Which Brands Grade Best and Worst
Every waterproof boot we've graded in our database, across both La Sportiva and Merrell lines, currently earns an F grade (20/100) for PFAS-related concern based on available materials and public disclosure. That is the honest headline, there is no standout "safe" winner among the models reviewed so far, and anyone shopping for waterproof footwear should treat that as the starting assumption rather than the exception. Waterproof membranes like Gore-Tex have historically relied on fluoropolymers and durable water repellent (DWR) coatings that belong to the broader PFAS chemical family, and that legacy shows up across brands, not just one.
Because none of the graded products clear the bar for "lower concern," this guide focuses on what separates the least-bad options from the rest, what claims brands make versus what's independently verified, and how to shop the category more defensively using our waterproof boots finder. If you're comparing footwear against other PFAS-heavy categories in your home, our general product finder can help you triage where to focus first.
Summary Comparison
| Product | PFAS Grade | Verdict |
|---|---|---|
| La Sportiva TX5 GTX Men's | F (20/100) | Avoid if minimizing PFAS is a priority |
| La Sportiva Women's Nucleo High II GTX | F (20/100) | Avoid if minimizing PFAS is a priority |
| La Sportiva Men's Eclipse GTX Hiking Boots | F (20/100) | Avoid if minimizing PFAS is a priority |
| La Sportiva TX Hike Mid Leather GTX | F (20/100) | Avoid if minimizing PFAS is a priority |
| Merrell Moab 3 8" Tactical Zip Waterproof | F (20/100) | Avoid if minimizing PFAS is a priority |
| Merrell Women's Moab 3 Mid Waterproof | F (20/100) | Avoid if minimizing PFAS is a priority |
| Merrell Men's Moab 3 | F (20/100) | Avoid if minimizing PFAS is a priority |
| Merrell Men's Moab 3 Mid Waterproof | F (20/100) | Avoid if minimizing PFAS is a priority |
Every grade above reflects our model-based estimate built from materials disclosure and public data, not an independent lab test of the finished boot. Scores can change as brands update sourcing or as new third-party testing becomes available.
La Sportiva Lineup, GTX Membranes Across the Board
La Sportiva's technical hiking and mountaineering boots lean heavily on Gore-Tex (GTX) membranes for waterproofing, which is the common thread pulling all four reviewed models down to an F grade.
La Sportiva TX5 GTX Men's pairs a suede and technical fabric upper with a Gore-Tex liner. La Sportiva markets the TX5 as a rugged approach/hiking hybrid, but the brand's public materials do not make a PFAS-free claim for this model. Pros, excellent grip and ankle support for technical terrain. Cons, fluoropolymer-based waterproofing is a known PFAS category, and no independent lab data was available in reviewed sources confirming a PFAS-free construction.
The Women's Nucleo High II GTX follows the same pattern, a synthetic and leather upper wrapped around a Gore-Tex membrane. Pros, lightweight for a mid-height hiker, good torsional stability. Cons, same membrane chemistry concern as the men's TX5, with no verified PFAS-free alternative offered in this line.
Men's Eclipse GTX Hiking Boots are positioned as a lighter-duty day hiker, again built around GTX waterproofing. Pros, more breathable and flexible than La Sportiva's mountaineering boots. Cons, the lighter build doesn't change the underlying membrane chemistry, so the F grade holds.
The TX Hike Mid Leather GTX adds a full leather upper, which some shoppers assume reduces chemical treatment. In practice, the leather is typically still finished with a DWR coating and paired with the same GTX liner, so the leather doesn't meaningfully change the PFAS profile based on available materials.
Merrell Moab 3 Family, Popular, Affordable, Same Chemistry Concern
Merrell's Moab 3 line is one of the best-selling waterproof hiking boot families in the U.S., and all four variants we reviewed carry the same F grade as the La Sportiva models.
Merrell Men's Moab 3 8" Tactical Zip Waterproof is built for tactical and duty use, with a side-zip entry and Merrell's proprietary "M Select DRY" waterproofing system. Merrell's marketing describes the boot as waterproof but does not, in the reviewed sources, make a specific PFAS-free claim for this model. Pros, durable, easy on/off, popular with law enforcement and outdoor workers. Cons, the waterproof membrane technology falls into the same PFAS-associated category as competitors.
The Women's Moab 3 Mid Waterproof and Men's Moab 3 Mid Waterproof are the brand's flagship mid-height hikers, prized for comfort out of the box. Pros, cushioned midsole, wide toe box, budget-friendly relative to technical alpine boots. Cons, same waterproof membrane concern, and no third-party PFAS testing was found in reviewed sources to confirm otherwise.
Merrell Men's Moab 3 (the non-waterproof low-top version referenced in our database) still scores an F, a reminder that grading reflects the full materials picture reported for the product line, not just the membrane, so even variants marketed with less waterproofing emphasis can carry similar underlying material concerns.
What to Avoid
- Unqualified "waterproof" marketing without a PFAS statement. If a listing emphasizes waterproofing but says nothing about the chemistry used, treat that as a signal to dig deeper, not a reassurance.
- Gore-Tex and generic "GTX" membranes without a specific PFAS-free sub-line callout. Gore has introduced some PFAS-free membrane products in recent years, but the boots in our database do not specify use of those newer materials.
- DWR-treated leather marketed as a "natural" alternative. Leather uppers are frequently finished with fluorinated DWR sprays, which can carry the same PFAS-associated concern as synthetic membranes.
- Vague brand sustainability language ("eco-friendly," "responsibly made") that doesn't specifically address PFAS or fluorochemical content.
Our Pick (and Why There Isn't a Clean Winner)
Based on available materials and data, we cannot point to a boot in this database that qualifies as lower concern; every model reviewed lands at the same F grade. That's a useful finding in itself, it suggests the waterproof boot category as a whole is still heavily dependent on fluorochemical membranes and DWR finishes, regardless of price point or brand positioning. If avoiding PFAS is your top priority, the more defensible strategy right now is to consider non-membrane options, such as oiled full-grain leather boots without a waterproof liner, paired with a separate wax-based conditioner you control, rather than assuming any factory-applied "waterproof" boot is automatically better. Check our waterproof boots finder
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