Waterproof jackets and other outdoor gear often rely on per- and polyfluorinated chemicals known as PFASs to repel moisture, and as you move around outdoors these chemicals migrate from your clothing into soil and streams where they can be taken up by plants and animals – including yourself!

Understanding how rain jackets are waterproofed can help you select gear that suits your individual needs and preferences.

Breathable membranes

Breathable membranes (also called waterproof breathable membranes, or WBMs) are key to creating jackets and pants that offer both rain protection and ventilation. They’re usually attached to an outer face fabric in terms of density, thickness and durability – protecting it from potential damage while simultaneously helping the membrane wick away sweat away from your body so you don’t end up sweating in it all day long!

Gore-Tex is one of the best-known waterproof/breathable membranes available, often enclosed within 2- or 3-layer fabrics encasing it to provide extra breathability and protection from sweat and oils that could clog its microscopic pores, leading to garments feeling sticky in wear.

Dermizax, made of hydrophilic Dermizax membrane material fabricated from polyurethane and fully recyclable, is another breathable membrane available, used by outdoor brands such as Rab and Montane, while electrospun membranes from The North Face’s FUTURELIGHT boast higher tensile strength for greater durability.

Water-repellent coatings

Water-repellent coatings are applied to fabrics after their initial textile waterproof agent finishing process to produce more functional fabrics that can withstand rain and oil, while still allowing sweat from our bodies to escape, thus preventing it from building up inside garments.

The coating contains microscopic geometry of pillars which deprive water of any solid surface to settle on, forcing it off of the material surface and away. This technology has been in use since 1960 when first employed on automobile bodies and windshields.

Montbell’s Versalite rain jacket uses DWR coating as one of its key ingredients, providing exceptional breathability and weather protection for around $250. This jacket combines Gore Windstopper fabric, nylon ripstop material, minimal seams plus seam taping plus seam taping along with DWR treatment to withstand moderate rainfall conditions. Care instructions call for tumble drying with heat treatment in order to reactivate its DWR properties and stay ready for the next rainfall shower.

Maintenance

Durable Water Repellent (DWR) surfaces on all waterproof jackets, pants and tents require regular care in order to function optimally. Without frequent washing of them, dirt may accumulate and damage their membrane or fabric material causing holes, jammed zippers or leakage issues.

As well as washing your gear as detailed above, re-waterproof it with products such as Revivex Wash-in or Nikwax TX Direct Spray-On. Be sure to select products which do not contain PFAS chemicals which have been identified by Ecology as harmful.

Repairing or reproofing old clothing and equipment is an economical alternative to buying new gear, while keeping more items out of landfills for reuse by other outdoor enthusiasts. Repairing or reproofing is much better for the environment than discarding something with plenty of life remaining; don’t let tears or wear prevent you from exploring!

Storage

Waterproofing technology found in outdoor apparel is essential to your comfort and safety on hiking trails or mountain summits. Without it, sweat can seep through and cause chills or hypothermia in extreme cases – which in turn affects performance by slowing your pace down or making you uncomfortable.

Non-breathable waterproof fabrics remain popularly used for low intensity activities in extreme weather conditions; however, most high performance jackets and trousers today use breathable membranes that allow sweat vapor from within to escape and thus keep both external water as well as your own moisture vapor out – thus keeping you dry from both sources of moisture vapor. PFAS chemicals (such as 3M’s Scotchgard) used in treatments like these have since been classified as dangerous substances so manufacturers have developed safer solutions.

Routine cleaning and reapplication of DWR treatments will keep your waterproof clothing performing at its peak level of rain protection. Should it wear off through friction, abrasion, or excessive use, simply use a DWR reactivator spray according to manufacturer recommendations and you’re back in action!