Waterproof vs. water resistant materials: what’s the difference?
If you're regularly exposed to the elements – whether hiking, climbing, ski touring, or just living your life – the right gear is key. Especially in changing weather, it often comes down to one common question: What type of clothing will actually help you stay dry? In this guide, we’ll tell you what waterproof, water-resistant, and water-repellent really mean, what those hydrostatic head numbers really mean, and what to watch out for when upgrading your equipment.
What do waterproof, water-resistant and water-repellent actually mean?
While at first glance these terms sound pretty much interchangeable, they’re anything but. In fact, they represent totally different levels of protection from moisture. Here's the breakdown:
Water-repellent: Clothing that is water-repellent makes water bead up and roll off. The surface has a treatment – usually DWR (Durable Water Repellent). However, the effect wears off over time, and will only protect you from light rain or drizzle.
Water-resistant: The term water-resistant isn't clearly defined, but it's usually used for products that can handle some moisture – but without being completely waterproof. Think softshell jackets or outdoor pants which repel light rain, but will eventually soak through in a downpour.
Waterproof: A garment is considered waterproof when it keeps you reliably dry in heavy, sustained rain. This is achieved through specialized membranes like GORE-TEX Pro , Mammut's various DRY technologies, or Pertex® Shield which all block rainwater from getting in while letting sweat vapor escape. On top of that, seams, zippers, and transitions are sealed to prevent any moisture from sneaking through.
Hydrostatic head: How do you actually measure waterproofing?
The hydrostatic head (HH) rating tells you how much water pressure a material can handle before water starts seeping through the fabric. It's measured in millimeters and based on a standardized lab test.
5,000 mm: good for everyday use and light rain
10,000 mm: solid protection in moderate rain and short downpours
15,000-20,000 mm: perfect for longer alpine tours and heavy rain
25,000 mm and up: built for use in extreme conditions (expeditions, ice climbing)
That being said: The HH-rating is just one piece of the puzzle. What really matters is whether the seams of your garment are taped, the zippers are sealed, and the fit complentes your activity.
Waterproof materials in real life: Hardshell vs. Softshell
How do different waterproof technologies actually perform in the field – and which tech works best for what? This section breaks down how hardshell and softshell materials are built, what they can handle, and how common membranes like GORE-TEX®, Pertex® Shield, and Mammut DRY stack up against each other.
GORE-TEX® vs. Pertex® Shield, vs. Mammut DRY
To understand how these membrane technologies differ, let's dive into the three main options Mammut uses in their waterproof jackets:
GORE-TEX®: Famous for its structure (originally microporous, now also hydrophilic), the membrane reliably blocks rain and wind while staying breathable. The pores are 20,000 times smaller than a water droplet, but still allow sweat vapor escape. GORE-TEX® is the go-to for mountaineering jackets, ski touring, or high alpine conditions – anywhere you need the best possible weather protection.
Pertex® Shield: This technology combines a waterproof, windproof membrane with high breathability. It's lighter than GORE-TEX®, making it perfect for minimalist tours, trail running, or brisk hiking. Despite being lightweight, Pertex® Shield provides reliable protection for any weather conditions.
Mammut DRY: Mammut's in-house membrane technology offers at least 10,000 mm HH-rating and comes in three variants: DRY Tour, DRY Active, and DRY Expedition. Depending on your requirements, they’ll provide the perfect balance between protection, weight, and breathability. Especially in performance gear, Mammut DRY is a sustainable and functional choice.
In the outdoor world, you'll mainly encounter two types of shell jackets: hardshells and softshells.
Hardshell – reliable protection against the elements
Hardshell jackets are the gold standard when conditions get ugly. They're composed of a tough outer fabric and a waterproof membrane like GORE-TEX®, Mammut DRY technology, or Pertex® Shield. They're completely windproof, permanently waterproof, and breathable at the same time.
Mammut offers several options:
Mammut DRY Tour : perfect for classic hiking and trekking adventures
Mammut DRY Active : ideal for high-intensity mountain activities where weight and function matter most
Mammut DRY Expedition : built for extreme conditions and maximum performance
The best thing: Many models also come with a wide range of handy features like pit vents, helmet-compatible hoods, as well as an ergonomic fit.
Softshell – built for better movement and added comfort
Softshell jackets are typically only water-repellent or low-level water-resistant – they usually have a membrane, but skip the sealed seams in favor of better breathability and flexibility. In dry, cold conditions or during high-output activities, they give you a solid combo of protection and comfort. However, for serious downpours, they're not your best bet.
Choosing the right level of protection for your activity [H2]
So when should you go with a hardshell – and when is water-resistant or water-repellent enough? Here's the breakdown:
What You're Doing | Protection Needed |
City & day-to-day | water-repellent or lightly water-resistant |
Day hiking | waterproof (depending on forecast) e.g., Mammut DRY Tour |
Alpine routes / via ferrata | waterproof (at least 15,000 mm) |
Ski touring / snowshoeing | waterproof, breathable, sturdy e.g., Mammut DRY Active and Mammut DRY TOUR |
Expedition / ice climbing | Hardshell, max water column e.g., GORE-TEX® Pro and Mammut DRY Expedition |
Care & reproofing – keeping your gear in shape
To ensure your waterproof clothing will offer you long-term protection, regular care is essential. Dirt, sweat, and wear eventually compromise the DWR treatment, and clog the membrane's pores.
Washing
Before you put in your gear, run your washing machine empty to clear out any fabric softener or powder detergent residue that may be left from previous washes.
Always follow the care label instructions.
Use liquid detergent designed for technical clothing (no powder detergent).
Skip fabric softener or bleach – they may destroy the membrane and reduce breathability.
Wash on a gentle cycle with low spin speed (max 800 rpm).
Refreshing the DWR Treatment
After several washes, or when water stops rolling off your jacket, it's time to refresh the treatment:
Use a DWR reproofing spray (water-based is good) that's made for technical clothing.
Spray evenly on the clean, slightly damp jacket.
Activate with heat: Either tumble dry on low or use an iron (with a cloth in between).
For more detailed info, check out our guide on properly caring for hardshell jackets with GORE-TEX membranes.
Trust the right protection
From water-repellent to water-resistant and waterproof – the differences really show when you’re exploring the great outdoors. If you're regularly navigating alpine surroundings or exposed to treacherous weather, spending on quality materials and high HH-ratings will go a long way. Hardshell jackets with GORE-TEX®, Pertex® Shield, or Mammut DRY membranes give you reliable protection, even under extreme conditions.
With proper care and regular reproofing, your gear will keep performing at its best – keeping you dry regardless of what nature throws at you.
