Will it still get wet even if I wear a waterproof jacket? Teach you the difference between "waterproof" and "water-repellent"!

After several days of torrential rain, with periods of on-and-off showers, some have asked: "Why don't the water droplets slide off the surface of my jacket when it rains, and why does it even absorb the water? Does this mean my jacket is no longer waterproof?" This is likely because the DWR (Durable Water Repellent) effect on the outer fabric has weakened, meaning water no longer beads up and rolls off; however, the outer fabric absorbing water does not necessarily mean the inner waterproof membrane has failed. With so many waterproof products on the market, waterproof jackets are no longer exclusive to mountain climbing, camping, or hiking. Living in the city, we face the possibility of rain at any moment. Today, let’s take a look at the differences in various levels of waterproofing!

Water Repellent

TRANZEND Ultra Suit 1.0

Also known as "water-resistant" or "splash-proof," this refers to the hydrophobicity of the fabric. A chemical coating is usually applied to the surface of the garment so that the surface tension of the fabric is lower than the cohesive force of water. When raindrops or moisture come into contact with the outer fabric, they form beads and roll off. This method is called DWR (Durable Water Repellent) treatment. Fabric treated with DWR is not truly waterproof; it only reduces the possibility of the fabric absorbing moisture. If moisture remains on the surface for a long time, it will still penetrate.

However, fabric treated with DWR is not permanent, and the water pressure it can withstand is limited. The water-repellent layer on the fabric will gradually weaken with washing, wear and tear, and prolonged use. Especially when the fabric structure is washed by a strong stream of water, moisture remains on the fabric for too long, or it is covered/penetrated by oil stains, the functionality of the water-repellent treatment will be greatly reduced and eventually fail. This is the reason behind the situation mentioned in the introduction: "Why don't the water droplets slide off the surface of my jacket, and why does it even absorb the water?"

Waterproof

(Ultra Suit 1.0) 

Next is waterproof, where the focus is on the fabric's ability to resist water penetration. Waterproof and breathable fabrics achieve excellent waterproof performance through weaving techniques, materials, and additives. These are generally divided into two types: Coating and Lamination. Coating refers to a layer applied to the fabric, while lamination involves bonding a waterproof membrane to the back. Most commercially available waterproof models are produced using the lamination (membrane) method, bonding a waterproof membrane to the outer fabric through a lamination process to form a composite fabric.

(Ultra Coat's outer layer is treated with DWR, and the middle layer is the AIRMEM™ nano eco-friendly coffee waterproof membrane, with a water pressure resistance of up to 15,000mm, providing highly efficient wind and rain protection while maintaining high breathability.)

The outer fabric of a waterproof jacket is usually also treated with DWR. When the water-repellent effect weakens, the outer fabric may absorb water and become damp, but the inner waterproof membrane can still normally block rain. To judge the protective effect of the entire jacket, one must also look at seams, zippers, openings, and wearing conditions; moisture inside the garment can also come from sweat and condensation, so it cannot be judged solely by whether water beads form on the surface.

Water Pressure Resistance (mmH2O)

(The fabric water pressure resistance for the historic model Ultra Suit 1.0 is 15,000 mm; this data does not apply to other generations or models.)

For test methods, refer to: ISO 811 Hydrostatic Pressure Test, ISO 4920 Surface Wetting Test, AATCC TM22/TM127.

Conclusion

Can you now tell the difference between "waterproof" and "water-repellent"? The waterproof membrane is responsible for resisting water penetration, while DWR helps water beads slide off the outer fabric; they work together. Water-repellent effects are affected by dirt, washing, and wear, and waterproof structures also require proper care. Please clean according to the garment's wash label first, then judge whether it is suitable to reapply a water-repellent treatment based on the care instructions for that model; do not treat all functional jackets with the same spray or heating method.

Thank you all for reading! I wonder if anyone else, like our editor, stops carrying an umbrella once they have a waterproof jacket, thinking it looks cool not to use one in the rain XD. Welcome to comment below and compete!

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