Is Nylon Waterproof

Picture this: you’re caught in a sudden downpour, wearing your favorite nylon jacket. At first, the rain beads right off. You feel invincible. But ten minutes later, you’re soaked through. What happened?

That experience captures the nylon waterproofing debate perfectly — and the answer is more layered than a simple yes or no.

What “Waterproof” Actually Means

Before judging nylon, it helps to understand what the word waterproof genuinely means. The fabric industry uses three distinct terms that most people blur together:

Calling nylon “waterproof” without context is like calling a screen door “windproof.” It slows things down — but it won’t hold forever.

So, Is Nylon Waterproof?

The straight answer: nylon is not inherently waterproof, but it is naturally water-resistant.

Raw nylon fabric has a tight weave that slows water absorption significantly better than cotton or wool. Water beads on its surface initially rather than soaking straight in. But nylon is a hydrophilic fiber — meaning at the molecular level, it actually attracts moisture. Given enough time or pressure, water wins.

The good news? Nylon responds exceptionally well to waterproof treatments, which is why it dominates the outdoor gear and rainwear industries.

The Science Behind Nylon and Water

Nylon is a synthetic polyamide polymer, first developed by DuPont in the 1930s. Its molecular structure contains amide bonds that carry a slight electrical polarity — and water molecules are polar too. This is why untreated nylon absorbs roughly 4–8% of its weight in water, depending on the specific type.

Compare that to cotton, which can absorb 25–27% of its weight, and nylon looks impressively water-smart. But compare it to polyester, which absorbs less than 0.4%, and nylon starts looking thirsty.

Think of nylon’s relationship with water like a popular café on a rainy day — it can handle the crowd for a while, but given long enough, everyone gets through the door.

Why Nylon Still Performs Well Despite Being Hydrophilic

• Tight weave density physically blocks water droplets from passing through
• Smooth fiber surface causes water to bead rather than wick inward immediately
• Fast drying time — nylon releases absorbed moisture quicker than most natural fibers
• Low absorbency compared to natural fibers means less soggy weight when wet

Types of Nylon and How Each Handles Water

Not all nylon is built the same. The performance gap between types is significant, especially in wet conditions.

Nylon 6 vs. Nylon 6,6

Ripstop Nylon

Ripstop nylon is woven with a reinforcing crosshatch pattern. It’s lighter, stronger, and — when coated — one of the most water-resistant fabrics available. It’s the backbone of tents, rain flies, and ultralight backpacking gear for exactly this reason.

Coated Nylon

When manufacturers apply coatings to nylon — polyurethane (PU), silicone (silnylon), or thermoplastic polyurethane (TPU) — the result crosses from water-resistant into genuinely waterproof territory. A silicone-coated ripstop nylon used in a quality tent rainfly, for example, can withstand a hydrostatic head of 1,500–3,000mm, meaning significant water column pressure before any leakage.

Nylon vs. Other Fabrics: The Wet-Weather Comparison

Nylon punches well above its weight class compared to natural fibers. Against technical fabrics like Gore-Tex, untreated nylon doesn’t compete — but treated nylon comes remarkably close at a fraction of the cost.

What Actually Happens When Nylon Gets Wet

Understanding the process makes the fabric’s limitations clearer.

Stage 1: Initial Water Contact

Water droplets hit the surface and bead. The tight weave and smooth texture resist penetration. This is where nylon shines and earns its water-resistant reputation.

Stage 2: Sustained Exposure

As rain continues or the fabric faces pressure (sitting against a wet surface, for example), water begins forcing through the weave gaps. This is wetting out — the point where resistance fades.

Stage 3: Absorption

The hydrophilic amide bonds in nylon start drawing in moisture. The fabric feels damp and heavier. Performance degrades.

Stage 4: Drying

Here’s where nylon redeems itself. It releases moisture much faster than cotton or wool, thanks to low fiber absorption and smooth structure. On a breezy day, wet nylon can feel dry within 30–60 minutes of leaving the rain.

How to Make Nylon More Waterproof

If you need nylon to perform in serious wet conditions, these methods genuinely work.

DWR Treatment (Durable Water Repellent)

DWR coatings are the most common solution. Applied at the factory or via spray-on products like Nikwax or Grangers, DWR causes water to bead aggressively on the fabric surface. Over time and washes, DWR degrades — but it’s easy to reactivate.

To restore DWR on nylon gear:

1. Wash the item with a technical fabric cleaner (avoid regular detergents)
2. Tumble dry on low heat for 20 minutes — heat reactivates existing DWR
3. If beading doesn’t return, apply a spray-on DWR treatment while the fabric is still damp
4. Let dry flat or hang dry

PU and Silicone Coatings

For gear rather than apparel, polyurethane or silicone coatings applied directly to nylon create a waterproof barrier. Silicone-coated nylon (silnylon) is ultralight and nearly impermeable — ideal for tarps, tent footprints, and stuff sacks.

Seam Sealing

Even perfectly waterproof nylon fabric leaks through needle holes at seams. Seam-sealing tape or seam sealant eliminates this weak point in tents, rain jackets, and dry bags.

Waterproof Laminates

High-end products bond a waterproof membrane (like ePTFE in Gore-Tex) directly to nylon fabric. The result combines nylon’s strength and abrasion resistance with true waterproofing. This is the gold standard in performance outdoor gear.

Best Applications for Nylon in Wet Conditions

Nylon’s water behavior — resistant but not proof, fast-drying, durable — makes it ideal for specific uses.

Excellent choices:

• Backpacks and day bags — water-resistant enough for most conditions, lightweight
• Swimwear and board shorts — dries rapidly, holds shape when wet
• Tents and rain flies (coated) — waterproof when properly treated and seam-sealed
• Rain jackets with DWR — highly effective for moderate rain
• Dry bags and stuff sacks — when coated, fully waterproof
• Umbrellas — nylon’s smooth surface sheds rain cleanly

Poor choices for water exposure:

• Uncoated nylon as sole protection in heavy, sustained rain
• Nylon base layers in cold-wet environments (wet nylon touching skin draws heat away)

Key Takeaways

• Nylon is water-resistant, not waterproof — it slows water penetration but doesn’t stop it indefinitely without treatment.
• Nylon is hydrophilic at the molecular level, meaning it eventually absorbs moisture, unlike polyester which largely repels it.
• Coatings and treatments transform nylon into a waterproof material — PU coatings, silicone, DWR spray, and waterproof laminates all dramatically improve performance.
• Nylon’s best waterproof advantage is its fast-drying speed — even when wet, it recovers quicker than most fabrics.
• Seam construction matters as much as fabric — waterproof nylon gear still needs sealed seams to prevent leaks.

Frequently Asked Questions (FAQ)

Can nylon be used in heavy rain without any treatment?
Untreated nylon handles light to moderate rain for short periods reasonably well, but it will eventually soak through under sustained heavy rain. For reliable protection in serious downpours, always look for DWR-treated or PU-coated nylon products.

What is the difference between water-resistant and waterproof nylon?
Water-resistant nylon repels surface water and slows penetration but isn’t sealed against sustained water pressure. Waterproof nylon has a membrane or coating (like silicone or polyurethane) that creates a physical barrier water cannot cross, even under pressure. The distinction matters enormously for outdoor gear selection.

How do I know if my nylon jacket has lost its waterproofing?
The clearest sign is water no longer beading on the surface — instead, it spreads out and soaks into the fabric (called “wetting out”). Washing the jacket and tumble-drying on low heat often restores existing DWR. If that fails, a spray-on DWR treatment will refresh the coating.

Is nylon or polyester more waterproof?
In their untreated forms, polyester is slightly more water-resistant because it’s hydrophobic — it repels moisture at the fiber level. Nylon absorbs slightly more water. However, when both are treated with the same coatings, performance is nearly identical, and nylon typically offers better abrasion resistance.

Why does nylon feel wet even when it “repels” water?
This usually happens because the DWR coating has worn down through use and washing. The outer fibers start absorbing water, making the fabric feel damp even though water isn’t fully penetrating. Restoring the DWR coating solves this immediately.

Can you waterproof nylon at home?
Yes, effectively. Products like Nikwax TX.Direct, Grangers Performance Repel, and Rust-Oleum NeverWet apply easily at home via wash-in or spray-on methods. Wash-in formulas work better for garments, while spray-on products give more precise coverage for bags and gear.

How long does waterproof nylon last before it needs retreating?
Under regular use and washing, DWR treatments on nylon gear typically last 10–20 wash cycles or one to two seasons of active outdoor use. Higher-end laminates (Gore-Tex bonded to nylon) last significantly longer — often 5–10 years with proper care — before performance noticeably degrades.