Waterproof vs Water Resistant Jackets: Ratings Explained

Waterproof jackets keep rain out entirely, while water resistant jackets only handle light moisture for a short time. The ratings on each jacket—measured in millimeters for waterproofing and in a separate scale for breathability—tell you exactly how much protection you get. This article explains what those numbers mean, how the fabrics work, and how to choose the right jacket for your needs.

What the Ratings Actually Measure

Waterproof ratings are expressed in millimeters (mm) of water column pressure. The test involves placing a fabric sample under a tube of water and measuring how high the water column can be before water seeps through. A higher number means the fabric can withstand more pressure before leaking. For example, a jacket rated 10,000mm can handle a column of water 10 meters high, which is enough for most heavy rain. Breathability is measured in grams per square meter per 24 hours (g/m²/24h), indicating how much moisture vapor can escape. A rating of 10,000g means the fabric allows 10 liters of sweat to pass through per square meter each day.

Waterproof vs. Water Resistant: The Core Difference

Water resistant jackets are treated with a durable water repellent (DWR) coating that makes water bead up and roll off. They are not fully sealed—the fabric still has tiny pores that water can eventually penetrate under pressure or prolonged exposure. Waterproof jackets, on the other hand, use a laminated membrane (like Gore-Tex or eVent) that physically blocks liquid water while allowing vapor to escape. The difference is not just in the fabric; waterproof jackets also have sealed seams, watertight zippers, and adjustable cuffs and hoods to prevent water entry through openings.

How the Ratings Are Tested

The hydrostatic head test is the standard method for measuring waterproofness. A fabric sample is clamped under a clear tube, and water is added until the first drop appears on the other side. The height of the water column in millimeters is the rating. For breathability, the test measures how much moisture vapor passes through a fabric over 24 hours, often using a cup of water sealed with the fabric. Industry standards classify jackets as water resistant (1,000–5,000mm), waterproof (5,000–10,000mm), or highly waterproof (10,000mm+). However, ratings can vary between brands because test methods may differ slightly.

Choosing the Right Rating for Your Use

Your choice depends on the intensity and duration of rain you expect, plus your activity level. Here is a practical guide:

• 1,000–5,000mm: Light showers, city commuting, or casual use. These jackets are often more breathable and packable.
• 5,000–10,000mm: Moderate rain, hiking, or cycling. They balance protection and breathability for active use.
• 10,000–20,000mm: Heavy rain, mountaineering, or extended exposure. These are built for serious conditions.
• 20,000mm+: Extreme weather, alpine expeditions, or professional use. Maximum protection, often with less breathability.

If you sweat a lot during activity, prioritize breathability. A highly waterproof jacket with low breathability can leave you wet from the inside, which is just as uncomfortable as rain.

Common Problems and Misconceptions

One common misconception is that a higher waterproof rating always means a better jacket. In reality, breathability is equally important. A jacket that is 20,000mm waterproof but only 5,000g breathable will feel clammy during exercise. Another issue is that DWR coatings wear off over time, causing the fabric to “wet out�—the outer layer absorbs water, reducing breathability and making the jacket feel heavy. This does not mean the membrane is failing; you can reapply DWR with a spray or wash-in treatment. Also, seam tape can degrade, and zippers can leak, so check those areas regularly.

How to Maintain Your Jacket’s Performance

To keep your jacket performing at its rated level, follow the care instructions on the label. Generally, you should wash it with a technical cleaner (not regular detergent) to remove dirt and oils that clog pores. Then reapply DWR to the outer shell. Avoid fabric softeners and high-heat drying, which can damage the membrane. Store the jacket loosely, not compressed, to prevent creasing that can break the membrane fibers. With proper care, a quality waterproof jacket can last for years.

Alternatives to Traditional Jackets

If you are looking for lighter options, consider a poncho or a rain cape, which offer excellent ventilation and full coverage but are less packable. For extreme conditions, a hardshell jacket with pit zips provides extra ventilation. Softshell jackets are water resistant but more breathable and stretchy, ideal for active use in light precipitation. For urban use, a waxed cotton jacket offers a classic look with moderate water resistance, though it requires periodic rewaxing. Each type has trade-offs in weight, packability, and protection.

Frequently Asked Questions

Is 10,000mm waterproof enough for heavy rain?

Yes, 10,000mm is generally sufficient for heavy rain. Most quality rain jackets fall in the 10,000–20,000mm range, which handles downpours without leaking. The main factor is the jacket’s construction—sealed seams and storm flaps matter as much as the fabric rating.

What does 5,000mm water resistant mean?

It means the fabric can withstand a water column of 5,000mm before leaking. This is suitable for light to moderate rain but may fail under heavy rain or prolonged exposure. It is often found on budget or urban jackets.

Can I make a water resistant jacket fully waterproof?

No, you cannot make a truly water resistant jacket fully waterproof. The DWR coating only adds surface repellency; the fabric itself is not impermeable. You can improve water resistance by reapplying DWR, but the jacket will still not match a membrane-based waterproof jacket.

Why does my waterproof jacket wet out?

Wetting out happens when the DWR coating wears off, allowing the outer fabric to absorb water. This reduces breathability and makes the jacket feel damp. It does not mean the membrane is leaking—you can restore performance by cleaning and reapplying DWR.

What is the difference between waterproof and water repellent?

Water repellent means the fabric is treated to cause water to bead and roll off, but it is not fully sealed. Waterproof means the fabric has a membrane that blocks liquid water entirely. Repellency is a property of the outer layer, while waterproofness is a property of the membrane.

How often should I reapply DWR?

It depends on use. For regular use, once or twice a year is typical. If you notice water soaking into the outer fabric instead of beading, it is time to reapply. Washing the jacket first with a technical cleaner improves DWR adhesion.

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