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Nylon Water Absorption: Moisture Regain & Real-World Use

What is the water absorbing capacity of nylon?

Nylon can absorb a small but meaningful amount of water compared with truly hydrophobic fibers. In typical apparel and pack fabrics, nylon’s moisture regain (the amount of water it holds from humid air) is commonly cited around 3%–5% by weight under standard conditions. That means nylon doesn’t “soak up” water like cotton, but it can still take on some moisture, especially over time and in high humidity.

When nylon is exposed to liquid water (rain, splashes, puddles), most of the water initially sits on the surface or passes through weave gaps rather than being absorbed into the fiber itself. However, the fiber can slowly absorb water, which may make the fabric feel heavier, slightly less stiff, and slower to dry than polyester in the same construction.

What changes nylon’s water absorption in real-world use?

Several factors can increase or decrease how much water nylon seems to absorb:

Fabric construction: A tight weave (like high-denier pack cloth) reduces water penetration, while looser weaves let water move through more easily.
Coatings and laminations: PU coatings, TPU films, or membrane laminates can block liquid water even if the nylon yarn itself has some moisture uptake.
DWR (durable water repellent): A DWR finish helps water bead and roll off, reducing wet-out and the perception of absorption.
Wear and contamination: Dirt, body oils, and abrasion can degrade DWR and make a nylon surface wet out faster.
Temperature and humidity: Higher humidity increases moisture regain; prolonged exposure gives the fiber more time to equilibrate.

Why does water absorption matter for bags and backpacks?

For backpacks, the practical concern is less about the nylon fiber absorbing a few percent of its weight and more about water getting through seams, zippers, and fabric pores. A nylon bag can still perform very well in wet weather when paired with a water-resistant build (coated fabric, sealed seams where needed, storm flaps, and quality zippers).

For a deeper look at how nylon backpacks handle rain—and what features improve water resistance—see this guide to waterproof nylon backpacks.

FAQ

Is nylon or polyester more water resistant?

Polyester generally absorbs less moisture than nylon, so it often feels less “damp” and can dry faster. In practice, coatings, DWR treatments, and fabric weave usually make a bigger difference than the base fiber alone.