DWR: What It Is, How It Works, and Why You Should Care When Choosing Outdoor Gear

What Is DWR (Durable Water Repellent)?

DWR, or Durable Water Repellent, is a chemical treatment applied externally to technical fabrics used in backpacks, tents, and outdoor apparel. Its primary function is to repel water, preventing the outer fabric from becoming soaked and preserving the performance of the equipment. Water forms small droplets that slide off the surface instead of being absorbed.

It’s important to understand that DWR is not the waterproof layer that prevents water from entering. The waterproof function is usually provided by internal membranes, such as Gore-Tex, event, or other technical materials. DWR acts as a first line of defense, preventing the outer layer from becoming saturated, which could reduce breathability and comfort.

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How Does DWR Work and Why Is It Essential?

When DWR is active, it prevents the outer layer of the fabric from absorbing water, keeping the equipment lightweight, breathable, and comfortable. If the outer layer becomes soaked (a phenomenon called “wet-out”), the internal membrane will still protect against water, but breathability is compromised, and the user may feel discomfort due to the sensation of dampness.

In backpacks and tents, DWR prevents water accumulation, avoiding extra weight and the development of mold, since these items are often stored while still slightly damp. In waterproof clothing, it enhances thermal comfort and helps maintain insulation efficiency.

Durable but Not Permanent: DWR Requires Regular Maintenance

Despite the term “durable,” DWR does not last forever. Friction, sun exposure, dirt, and frequent washing degrade its effectiveness. When this happens, water starts to be absorbed by the outer fabric, reducing protection and performance. To avoid this problem, regular maintenance is necessary:

• Proper cleaning: Use specialized products like Nikwax Tech Wash or Grangers Performance Wash to remove dirt and oils that affect DWR performance.
• Heat reactivation: After washing, many DWR-treated fabrics can be reactivated with heat from a dryer or a low-temperature iron. This process helps reorganize the treatment molecules, improving water repellency.
• Reapplication when necessary: If heat reactivation is insufficient, reapply DWR using sprays (such as Nikwax TX.Direct Spray-On) or wash-in solutions (Grangers Performance Repel Plus).

Important note: Nikwax products do not require heat reactivation, unlike many conventional treatments.

The Environmental Issue: The Dangers of PFCs

Historically, DWR treatments have been made with chemical compounds known as PFCs (Perfluorocarbons), including PFOA and PFOS. These compounds provide excellent water and oil repellency, but are extremely harmful to the environment. They do not break down easily and accumulate in nature, contaminating soil, water sources, and even humans and animals.

Studies have linked PFCs to health issues, including hormonal disorders and reproductive system damage. For this reason, many leading brands, such as Patagonia, Arc’teryx, The North Face, and Deuter, have transitioned to PFC-Free treatments, developing effective and environmentally safe solutions.

Nikwax and Grangers: Sustainable Solutions for DWR Maintenance

Two brands stand out in the international market for their sustainable and PFC-free solutions:

Nikwax

Specialized in water-based cleaning and maintenance products that do not require heat reactivation. Solutions like Tech Wash (cleaning) and TX.Direct (DWR reactivation) is highly effective. Nikwax also created the brand Páramo, which develops technical clothing without membranes, using only DWR. Among its products, I highlight the Alta III jacket, which I have been using for years in my outdoor activities, and I can confirm that it performs excellently in harsh conditions.

Grangers

With over 80 years of history, Grangers offers products such as Performance Wash and Performance Repel Plus, which clean and reactivate DWR in a single step. Their formulas are PFC-free and designed to maximize outdoor gear performance.

Practical Tips to Maintain Water Repellency

• Regular cleaning: Wash your gear using specialized detergents, such as those from Nikwax or Grangers. Do not use regular detergents, as they may remove the DWR.
• Avoid unnecessary washes: Only wash gear when needed to prolong DWR effectiveness.
• Reactivate with heat (when applicable): After washing, use a dryer on low heat or an iron as per the manufacturer’s recommendations.
• Reapply when necessary: If the fabric no longer repels water even after reactivation, apply a new DWR treatment.

Conclusion: Choose Responsible Brands and Preserve Your Gear

DWR is essential for outdoor gear performance, but choosing sustainable technologies is also as important.

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