Waterproof Explained

Explanation to the different levels to something been classed as waterproof.

Waterproofing is the sliding scale of how much water a fabric can endure before it lets any moisture through. Wait… what? Surely a fabric is either waterproof or it isn’t? Uh, you’d think so, but no. Anything about 3,000mm and above is rated as ‘waterproof’.

Waterproof ratings: what do the numbers mean?

Below 5,000mm

While ‘waterproofing’ begins at 3,000mm, anything up to 5,000mm is only going to stand up to a light shower, maybe some drizzle. Some outdoor jackets with this rating might be things like super lightweight and packable jackets. Snow jackets that have this rating are likely meant for the park or fair-weather riding, not for snowstorms or ploughing through powder!

5,000 - 10,000mm

Between 5,000mm and 10,000mm things are getting a little more stable. A lot of generic brand items will be in this range. They’re okay for resort skiing or boarding in good weather, but won’t stand up to much punishment and won’t be much use in the rain.

10,000 - 15,000mm

10,000mm or 10k is often the industry standard for branded snow goods. Very rarely will you see a branded piece of snow gear with less than 10,000mm of waterproofing if it’s designed for general use. This range has good resistance to the elements without breaking the bank, and is usually where the entry-level or standard gear from most brands slots in.

Gaerne DRYTECH liner is 10'000mm

15,000 - 20,000mm

15,000mm is quickly becoming the benchmark for many brands, and thanks to better technology, it’s more attainable than ever at an affordable price. 15,000mm is reliable and solid for use all over the mountain, in all weathers. 15,000mm is more waterproofing than most riders will ever need.

20,000 - 25,000mm

As we get above 20,000mm, you’re looking at serious performance. Most brands’ ‘performance’ or technical ranges tend to be in this category. Mass produced (i.e. generic, rather than patented brand specific) technical membranes usually top out at this kind of figure, but it’s more than enough for riding in even the worst weathers!

25,000mm and above

25,000mm is when you start to get into that more ‘black and white’ level of waterproofing, i.e. if it’s above 25k, then it’s never going to let water in. Gore-Tex offers a dryness guarantee, and it’s rated at 28,000mm, for reference! Anything sporting a 25,000mm water column or more is a serious piece of gear ready for the toughest adventures. Blizzards, hurricanes, you name it, let’s go!


Gore-Tex is the brand that single handily took waterproofing from non-breathable plastic sheets to breathable membranes. Heated and rapidly stretched PTFE creates a microporous synthetic fabric that keeps water out, but lets vaporised sweat through, for industry leading performance, decades on from its original conception. Their range now contains many different iterations, but all possess the same great performance.

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