The Outdoor Lab

Water Column Pressure & Repellancy

Read on about water column pressure technology and repellancy

What is a Water Column Pressure?

Water column pressure is an alternative way of expressing measurements of pressure. This measurement is defined as the pressure produced by a 1-inch by 1-inch column of water with a specified height on a product.

In case of a recycled nylon shell jacket the water column value tells how much the jacket is waterproof, i.e. rainproof.

In other words, how much water can it withstand before the water penetrates the jacket. Higher values ​​therefore logically mean more protection during rainy and wet conditions.

WCP scale & guide

How much Water Column Pressure do I need?

Typical waterproof level on activity


Winter / Early spring: 15.000 mm.

Spring / Summer: 0 - 5.000 mm.

Autumn / Early Winter: 10.000 - 15.000 mm

Alpine Conditions

Winter: 20.000 mm. +

Spring / Summer: 10.000 - 15.000 mm.

Autumn / Early Winter: 20.000 mm. +

Everyday Use

Winter: 5.000 - 10.000 mm.

Spring / Summer: 0 - 5.000 mm.

Autumn / Early Winter: 5.000 - 10.000 mm