Water-resistant fabrics do precisely as their name suggests, that is, resist water to lesser or greater degrees. Compared to waterproof varieties of garment, these products are less capable of preventing saturation from rainwater.
Unlike waterproof jackets, the ability of water-resistant varieties to repel moisture relies entirely on a durable waterproof repellent (DWR) coating that is applied to the outer fabric during production. This coating prevents water absorption by a process described in more detail in our guide to DWR waterproof coatings. In a few words, this coating (sometimes also referred to as a “lining”) causes water to bead up on the garment’s surface and run off before saturating the fabric.
- Suitable for light rain showers
- Generally less expensive
- Don’t have taped seams
- Treated with a DWR finish but don’t have a waterproof membrane
DWR ratings are determined by the percentage of fabric with no water sticking to it following a simple spray test. For example, if the DWR rating is 80, then 80% of the fabric was water-free after the spray test. A second figure indicates the garment’s performance in the same spray test after a number of washes. For example, a rating of 90/20 tells us that the fabric maintains a 90-point rating (being 90% water-free in the spray test) after 20 washes.
- 80 points/10 washes — The bare minimum for classification as DWR in most outerwear
- 80 points/20 washes — The typical DWR rating for most water-resistant garments
- 80 points/50+ — Exceptional water repellency, usually used in either very high-end waterproof products or garments which lack a waterproof membrane and rely only on DWR for water resistance
Waterproof garments usually combine a DWR coating on the outer fabric, fully taped seams, and a built-in membrane lining such as those described in our article on waterproof and breathable fabric (Gore-Tex, eVent, HyVent are a few of the most popular varieties).
A membrane lining is an incredibly thin film or sheet of material with literally billions of microscopic holes which are too small for rainwater to penetrate but large enough for water vapor molecules (from sweat) to pass through in an outward direction. This membrane assists breathability and forms a second, more impermeable barrier after the DWR outer.
- Suitable for heavier rain
- Use a waterproof fabric membrane (such as Gore-Tex, eVent, or HyVent)
- Outer layer treated with DWR (Durable Water Repellent) finish
- Taped seams
- Generally more expensive
The waterproof capacity of any garment is quantified by hydrostatic head ratings, which are covered in more depth in our guide What is Hydrostatic Head? The legal minimum hydrostatic head rating for classification as a waterproof garment is 1,500mm, which we’ll take as a starting point for the summary below.
- 1,500mm — 5,000mm = Can deal with only very light rain and, at that, not for sustained periods. Most commonly found in jackets intended for “casual”, everyday use than in performance models.
- 10,000mm = Suitable for light rain showers but liable to leak at pressure points where the straps of your backpack are in contact with the jacket (the shoulders, back, and belt area). Jackets with this rating often focus more on breathability than on waterproofing, as exemplified by Polartec Neoshell.
- 20,000mm = Capable of dealing with heavy rain showers and seen by some manufacturers as the max waterproofing capacity required.
- 30,000mm = Garments with this rating provide solid waterproofing in even the heaviest downpours, but occasionally at a cost to breathability. This HH rating is used in jackets and rain pants for hiking in extreme conditions, such as eVent’s DV Expedition models.