What is DWR? And How to Care For It

If your high tech rain jacket has been feeling a little damp lately it might be time to refresh its DWR coating. 

But, what is DWR and how do you care for rain gear with DWR? 

Keep reading for the answers to these questions and more. 

As always, skip ahead in the table of contents to quickly find what you are looking for; or skip straight to the full summary.

What is DWR?

DWR stands for Durable Water Repellant; a thin chemical layer or coating applied to fabrics to make them more water-repellant. 

The acronym DWR is used as a generic term for Durable Water Repllents that up until 2016 were almost entirely made of long chain perfluorocarbon (PFC) based materials. 

Since the 2016 FDA ban on PFCs in food packaging shed light on how harmful these substances can be, outdoor companies around the world have worked to create viable alternatives. 

More on this below, but important to know is, at the time of this writing, most gear manufacturers use either a shorter chain PFC or non-PFC based materials that are less toxic to both humans and the environment. 

How Does DWR Work?

DWR is made up of tiny pillars that bond with the base fabric, standing up and away from the fibers – like thousands of tiny umbrellas all lined up next to each other.

This decreases surface tension between water and the base fabric, allowing water droplets to maintain their spherical shape when they land on your jacket. 

Without this effect water droplets break apart, spread out, and soak into the material they land on. 

With DWR present, rather than making contact with thread fibers and soaking into your jacket, moisture beads up on top of the tiny DWR pillars, which then allows that moisture to roll off before it can to soak through. 

Have you ever watched water roll off a large leaf in the rain? That’s nature’s DWR. 

In addition, by keeping the spaces between a garment’s threads open and dry, DWR allows more usable surface area for moisture to escape from your body.

For this reason, waterproof jackets will almost always use DWR in conjunction with waterproof-breathable membranes like Gore-Tex or Pertex.

DWR helps keeps moisture from getting into the fabric so that the waterproof-breathable membrane can allow moisture from your body to get out. 

How Long Does DWR Last?

DWR wears out due to abrasion, contact with body oils, dirt and other contaminates, and with time. 

Most manufacturers suggest restoration or reapplication of DWR every 3-6 months when used regularly, but timing depends on both frequency and intensity of use as well as degree of exposure to moisture.

Running in a Seattle drizzle for example, won’t wear out your DWR as quickly as Alpine Climbing in the Rockies or thru hiking the PCT.  

For example, when using gear heavily, Arc’teryx suggests reapplication of DWR every 10-12 days.

When to Restore DWR

As DWR wears out, water doesn’t bead up and roll off your garment as well as it used to. 

This is a strong indication that it is time to restore or reapply your garment’s DWR.

You might notice your gear starting to “wet out,” in high abrasion areas like the elbows, knees, or shoulders. 

Wetting out refers to water pooling or soaking in certain areas rather than beading up and rolling off. 

This means the tiny DWR pillars discussed above have collapsed. Water droplets can now make complete contact with the fabric and soak in between the threads. 

Having a properly functioning DWR layer on your jacket is like keeping the lid closed on a cooler – the gear still works without the DWR or the cooler lid open, but optimal performance is achieved when both are fully optimized.

Restore or reapply your DWR when you notice wetting out, the performance goes down, or after prolonged periods of time and use. 

Additionally, it is good practice to restore DWR before a big trip or as the wet season ramps up in your area. 

When DWR wears out, you have two options: restore the existing DWR (also called reactivation) or reapply a new coat of DWR. 

Restoration vs. Reapplication of DWR

It sounds counterintuitive, but DWR is actually activated (and for our purposes, reactivated) by heat. 

Remember, as DWR wears out, the tiny pillars that should be upright start to collapse or break. 

The process outlined below helps bring those pillars back upright so that they can continue their job of keeping moisture off of and out of your garment’s fabric – ultimately helping you stay warmer and drier. 

Keep in mind, it is ideal to wash your gear before reactivating or reapplying DWR.

You can skip down to washing instructions here.

Restoring DWR

Restoring or reactivating DWR is a quick and easy way to improve a waterproof garments performance. 

Option 1: Tumble dry (preferably in a front loading dryer) your garment on low for approximately 20 minutes. Remove and hang to let it cool down. 

*Always check manufacturer care instructions before washing or drying a garment. Some outdoor gear cannot be placed in driers.

Remember to fully zip all zippers, remove all debris from pockets, release tension on all drawcords or strings, and secure all cuffs. 

Option 2: Iron your garment on low. Place a towel or similar material between the iron and the garment to prevent damage. Do not use steam. 

Remember to zip the zippers and check all pockets. An ironed piece of gum or electrolyte chew is not fun to deal with. 

Allow your garment to cool down then recheck its water-repellency by drizzling a handful of water over its surface. 

Water should bead and run off. If it pools or wets out (as shown in the image above), it’s probably time to reapply a new layer or DWR. 

How to Apply New DWR

Before applying new DWR it is recommended to first wash your waterproof garment. 

Always check the care label on your garment before starting this process. 

When possible, do not wash your waterproof gear with other garments and avoid over stuffing the washing machine (1-2 garments maximum per load).

Unless stated by the manufacturer, any regular liquid detergent is suitable when washing waterproof gear. Ideally, use the most gentle detergent available.

Do not use: powdered detergent, any amount of bleach, or fabric softeners. When possible, run your machine empty through a quick rinse cycle to clear out any residual bleach or other solvents.

If indicated by the product label or by personal preference, gear specific detergents like Nikwax Tech Wash are a readily available and inexpensive. 

3-Steps to Washing a Waterproof Garment

DWR works best when applied to a clean base layer. Follow the quick-clean process below to get your garment ready for a new layer of DWR. 

1. Prepare the Garment:
• Check care label for instructions and precautions.
• Completely empty all pockets
• Remove attached stickers or tickets such as ski-passes
• Fully zip all zippers, loosen draw strings, close flaps, snaps, and cuffs (open zippers or velcro may cause abrasive damage to the garment during washing).

2. Wash:
• Wash with ~30ml/1 ounce of gentle detergent or technical cleaner like Nikwax
• Wash on normal or gentle cycle at ~40 C/105 F (lower temperatures preferred)
• Add extra rinse to cycle if possible
• Use lowest spin setting
• Hang to dry or tumble dry on low
• Allow to dry completely

3. Reactivate:
• Tumble dry low for approximately 20 minutes
• Or, iron on low with a towel between the iron and your garment (do not use steam)

That’s it. Now you’re ready for a new layer or DWR. 

Reapplication of DWR

The process for reapplication of DWR will depend on which particular product you choose. 

Some treatments require heat to activate after application. Others like Nikwax TX.Direct Spray-On do not require heat for activation. 

Whatever DWR product you choose, always follow the manufacturers instructions found on the product label. 

In general, however, the process is as follows:

• Clean and fully dry your garment as per above
• Apply the product evenly to the outside of the garment
• Wait 5-10 minutes
• Pat dry any excess liquid
• Allow to fully dry or activate with heat if indicated

In the video below Gore-Tex runs through the process from washing to application of a new DWR layer. 

Spray-on vs. Wash-in DWR

In terms of performance, there is no real difference between wash-in versus spray-on DWR. 

In general, wash-in provides a bit more coverage as the DWR is able to penetrate seams, zippers, and all accessory material like cords and velcro. 

Wash-in DWR treatments are also less time consuming than spray-on products. You simply throw your garment in the washing machine with the liquid, wash it, and let it dry completely. Simple. 

Keep in mind, for best results, gently pre-wash your garment before applying either the wash-in or spray-on DWR treatment. 

Here are wash-in instruction directly from Nikwax for their TX.Direct Wash-In product: 

Environment, Safety & DWR

If you looked closely at the Nikwax product page above, you will notice it states that its product is contains zero PFCs. 

DWR is made of Perfluorocarbons or PFCs. 

Originally, this chemical compound was bound in a molecular chain sometimes referred to as “C8 long-chain fluorocarbon.”

The first iterations of DWR were extremely effective and durable but, it turns out, were also harmful to humans and the environment. 

One of the main problems with C8 PFCs is that they break down and bio-accumulate in the environment and in the human body. 

This means that over time hazardous effects can compound. 

While there is some controversy around this topic, many studies have shown adverse effects in both humans and other animals associated with increased PFC levels. 

Because of the concerning evidence and relative uncertainty around PFCs and DWR, companies like Nikwax do not use (Nikwax has never used) PFC based DWR. 

You can find a list of studies and resources on Nikwax’s blog page here. 

DWR, PFCs & The Future

As a result of the above findings many companies have been searching for a better water repellant alternative. 

Patagonia has adopted a C6 DWR that is considered less toxic. 

While C6 PFCs are not a complete fix, they are generally regarded as safer to use and manufacture than their C8 predecessors. 

Since 2008, through partnership with Blue Design, The North Face has been committed to more ethical and environmentally responsible product life cycles. 

Since 2017, The North Face has been transitioning their entire waterproof line to non-PFC materials.

All this to say, DWR is an incredible chemical technology that helps us stay drier so we can better enjoy our outdoor adventures. But, it is not without its pitfalls. 

The outdoor industry has recognized the shortcomings of DWR, and fortunately for adventurers like us, they continue to offer better and more responsible products. 

Summary

DWR stands for Durable Water Repellant. 

In the past the term was used generically for PFC (perfluorocarbon) based materials used to create a highly durable water repellant layer that was coated onto base fabrics. 

DWR works by stacking microscopic pillars on a fabric’s surface. These pillars allow moisture to bead up and roll off a garment rather than dispersing and seeping into or between microfibers. 

Overtime due to use – exposure to body oils, dirt, and the environment – DWR can lose its water repellant properties. 

When this occurs, you will likely notice areas of wetting out soaking on your garment. 

Thankfully, DWR can easily be both reactivated and reapplied. 

Here is Craig from ProLite Gear with a quick review of everything DWR:

Now you know what DWR actually is and when you might need to reactivate or reapply DWR to your outdoor gear.

Stay dry out there and keep venturing forward!