DWR – All the waterproofing technology amounts to nothing without the most important part of the equation: Durable Water Repellent (DWR). DWR is a chemical coating that is treated to the face fabric (the exterior layer) in order to make it completely hydrophobic. Without DWR, the exterior fabric can get “wetted out” and suffer from reduced breathability or even cause a reverse effect in that moisture is “sucked in” to the fabric, causing the garment to get completely soaked inside and out.
DWR is a chemical treatment (usually silicon based) that is applied on the fabric in the factory, but it wears off over time. The main reason for DWR wear is abrasion, so areas that suffer in particular are where straps, harnesses, gaiters and other bits of gear create friction on the fabric. In order to keep the fabric from wetting out, it is important to re-apply the DWR on a regular basis, along with giving the garment a good clean.
For best results remove all non-washable parts and always clean item(s) first with Nikwax Tech Wash®. No need to dry item(s) before waterproofing.