The difference between waterproof finishes, explained

"Waterproof", "water-resistant", "showerproof", "waterproof and breathable" — the labels on outdoor jackets are a minefield, and they're not interchangeable. Knowing the difference saves you money and stops you buying the wrong thing for a wet Welsh hillside. Here's what the terms actually mean, in plain English, from people who sell the stuff for a living.

The two layers doing the work

A proper waterproof jacket keeps you dry with two different things working together — and most confusion comes from mixing them up.

1. The DWR — the bit that makes water bead

DWR stands for Durable Water Repellent. It's an invisible treatment on the outer face of the fabric that makes rain bead up and roll off. It is not what makes a jacket waterproof — it's the first line of defence, and crucially, it wears off with use, washing, and grime. When you see an older jacket where the outer fabric goes dark and soaks up water, that's the DWR failing.

2. The membrane or coating — the actual barrier

Underneath sits the real waterproof layer: either a laminated membrane (Gore-Tex and similar) or a PU coating on the inside of the fabric. This is what physically stops water getting through. Membranes are generally more breathable and durable; coatings are cheaper and still effective but tend to be less breathable.

What "breathable" really means

A waterproof that isn't breathable keeps the rain out but traps your sweat in — so you arrive damp anyway, just from the inside. "Waterproof and breathable" means the membrane lets water vapour (sweat) escape while blocking liquid water from getting in. No jacket is infinitely breathable, though — on a hard climb you'll always generate more sweat than any fabric can shift, which is why pit zips and vents exist.

How waterproof is waterproof? The mm rating

Waterproofing is measured as a hydrostatic head in millimetres — how tall a column of water the fabric holds back before it leaks. A rough guide:

• 1,500mm — the minimum to legally be called "waterproof" in the UK. Fine for light showers.
• 5,000mm — handles steady rain and everyday hill walking.
• 10,000–20,000mm — serious, sustained wet weather and mountain use.

"Showerproof" or "water-resistant" means there's no real membrane — just a DWR and tightly woven fabric. It'll see off a passing shower, not a day on the tops.

Taped seams — the detail that matters

Every stitch is a needle hole, and water finds holes. A true waterproof has its seams taped on the inside. "Fully taped" means every seam; "critically taped" means just the most exposed ones. No taping, no matter the fabric rating, and it'll leak at the shoulders.

"My expensive jacket is leaking" — usually, it isn't

This is the most common thing we hear, and nine times out of ten the membrane is fine — the DWR has worn out. When the outer fabric stops beading and "wets out" (soaks through), two things happen: it feels clammy, and breathability collapses, so your own sweat condenses on the inside. It feels exactly like a leak. The fix isn't a new jacket — it's reproofing.

Keeping a waterproof working

• Wash it — but with a technical wash, never normal detergent. Detergent leaves a residue that kills both the DWR and breathability. (Nikwax Tech Wash is what we use.)
• Reproof it — a wash-in or spray-on DWR like Nikwax TX.Direct restores the beading once it fades.
• Warm it through — gentle heat (a cool tumble dry or a warm iron through a cloth, if the care label allows) helps reactivate the DWR.

Done once or twice a year, this keeps a good jacket performing for many seasons.

The same applies to boots

Leather and fabric boots rely on the same principles — a water-repellent surface over a waterproof membrane or treated leather. They need proofing too, and they're easy to forget. Our guide to choosing walking boots covers fit and care, and the proofings that keep them dry are in the same range as your jacket's.

Come and feel the difference

The easiest way to understand all this is to handle a few jackets side by side — a showerproof against a fully taped, high-rating waterproof — and see what you're paying for. Browse our waterproofs and proofings, then come into 7 The Mount, Heswall, or call 0151 342 4538, Mon–Sat 9–5:30. Heading out locally? Our Wirral walks guide tells you which of these you'll actually need where.

FAQs

What does the mm rating on a waterproof jacket mean?

It's the hydrostatic head — how much water pressure the fabric resists before leaking. 1,500mm is the legal minimum for "waterproof"; 5,000mm suits general hill walking; 10,000–20,000mm is for sustained mountain weather.

Why does my waterproof jacket feel wet inside if it isn't leaking?

Almost always because the outer DWR has worn off and the fabric has "wetted out". That stops it breathing, so your own sweat condenses inside. Wash it with a technical wash and reproof it, and it'll feel like new again.

Can I wash a waterproof jacket in the machine?

Yes — in fact you should, because dirt clogs the membrane. But use a dedicated technical wash, not ordinary detergent or fabric softener, which leave residues that ruin both waterproofing and breathability.

What's the difference between showerproof and waterproof?

Showerproof (or "water-resistant") means a water-repellent finish but no real membrane — fine for a brief shower. Waterproof means a genuine membrane or coating with a measurable mm rating and taped seams, built to keep you dry in sustained rain.

How often should I reproof my waterproofs?

When water stops beading on the surface and starts soaking in — for regular walkers, roughly once or twice a year. Reproof the moment you notice "wetting out" rather than waiting for it to feel like a leak.