What Makes a Rain Jacket Truly Waterproof? Gore-Tex vs Coated Fabrics Explained

The short answer

A rain jacket keeps you dry with three things working together: a waterproof membrane or coating, taped seams, and a water-repellent (DWR) outer finish. Gore-Tex is one well-known membrane, not the only one. Many good jackets use a brand’s own membrane, and a cheap jacket can be fully waterproof but feel like a plastic bag.

The difference you pay for is mostly breathability and durability, not just “waterproof or not”. This guide explains the parts, from someone who has spent more than 14 years working on fabric finishes.

The three layers of protection

• Membrane or coating. A very thin layer bonded to the inside of the fabric. It has pores too small for liquid water to pass but large enough for water vapour (sweat) to escape. That is what “waterproof breathable” means.
• Taped seams. Every stitch is a tiny hole. A waterproof jacket has tape sealed over the seams on the inside. Without it, water gets in at the shoulders first.
• DWR finish. A durable water-repellent treatment makes rain bead up and roll off the outer fabric. When it wears off, the outer fabric “wets out”, the jacket feels cold and clammy, and breathability drops, even though the membrane is still keeping rain out.

Gore-Tex, own-brand membranes and PU coatings

Type	How it works	Breathability	Durability	Typical use
Gore-Tex membrane	Microporous membrane bonded to the fabric	High	Very good; Gore also guarantees jackets made under its licence	Hiking, travel, everyday rain in cold or wet climates
Brand membranes (for example DryVent, H2No, Helly Tech)	The brand’s own membrane or coating system	Good to high	Good	Everyday and outdoor jackets at a lower price
PU coating	A polyurethane layer painted on the inside	Lower	Can peel or crack after a few years	Budget rain jackets, ponchos
PVC or rubberised	A solid plastic layer	Very low	Tough but stiff	Fishing, work and fashion raincoats

One example I found while researching: The North Face Antora, a popular, well-reviewed jacket that appears in Gore-Tex searches on Amazon Australia, actually uses The North Face’s own DryVent membrane, not Gore-Tex. It is still a good jacket. The point is to read the product details, not the search results.

Reading waterproof ratings

Waterproofing is measured as hydrostatic head, in millimetres: the height of a water column the fabric can hold back.

• 5,000 mm: light rain and showers.
• 10,000 mm: steady rain; enough for most city use.
• 20,000 mm and up: heavy, long-lasting rain and pressure from backpack straps.

Breathability is often given in g/m²/24h (how much water vapour passes). Above about 10,000 is good for active use. Gore-Tex does not always publish these numbers, because it tests whole garments instead.

2-layer, 2.5-layer or 3-layer?

• 2-layer: membrane bonded to the outer fabric, with a loose mesh lining. Comfortable for everyday wear.
• 2.5-layer: a thin printed protective layer instead of a lining. Very light and packable, a little clammy inside.
• 3-layer: outer fabric, membrane and inner fabric bonded together. The most durable; used in hiking and mountain jackets.

Looking after a waterproof jacket

Wash it occasionally with a technical wash, not normal detergent or softener, which clog the membrane. Rinse well. Most DWR finishes recover with gentle heat, so tumble dry on low if the label allows. When rain stops beading, reproof it with a spray-on or wash-in DWR product.

Frequently asked questions

Is Gore-Tex really waterproof?

Yes. Gore-Tex membranes are waterproof and windproof. Most leaks in Gore-Tex jackets come from open zips, worn cuffs or water running in at the neck, not through the fabric.

Is Gore-Tex worth it in Australia?

For hiking, Tasmania, the Alps or long walks in heavy rain, yes. For a short city commute in Sydney or Brisbane, a jacket with a good brand membrane is usually enough.

Why does my rain jacket feel wet inside?

Usually it is sweat condensing on the inside, because the outer fabric has wetted out and breathability has dropped. Washing and re-treating the DWR often fixes it.

What is a good waterproof rating for a rain jacket?

10,000 mm for everyday use; 20,000 mm or more for hiking and heavy rain.