How to Reproof a Waterproof Jacket (and Why It Wets Out)

A waterproof jacket that has stopped keeping you dry is usually not broken. Nine times out of ten it has simply stopped repelling water at the surface, which is a job for a wash and a bottle of proofer, not the bin. Learning to spot the difference, and to fix the fixable version, is one of the cheapest ways to get years more out of a shell you already own.

This guide covers the whole process: how to tell reproofing is what you actually need, why the jacket lost its edge in the first place, and the step by step for both wash-in and spray-on proofers. It applies to any technical waterproof, from a budget packable to a 3-layer mountain shell.

How to tell if it needs reproofing

The test takes ten seconds. Hold the jacket under a tap or flick water across the shoulders and sleeves, and watch what the water does.

If it beads up into little balls and rolls off, the water-repellent finish is working and the jacket is fine. If the fabric goes dark and the water soaks in rather than beading, that is "wetting out", and it is the clearest sign the jacket needs cleaning and reproofing.

Wetting out is not the same as leaking. The waterproof membrane sits underneath the outer face fabric, and when the surface wets out that membrane is usually still intact. The problem is that a saturated face fabric feels cold and clammy, adds weight, and kills breathability. When the outer soaks through, a waterproof-breathable jacket can lose a large share of its breathability, so sweat has nowhere to go and you get damp from the inside. That is why a jacket that wets out often feels like it is "leaking" when it is not.

Why a waterproof stops being waterproof

There are two very different failures, and only one of them is fixable at home.

DWR wearing off (fixable). The outer face fabric is treated at the factory with a Durable Water Repellent, or DWR. It is a thin coating that makes water bead rather than soak in. DWR wears away with use, abrasion from a rucksack, body oils, sun cream, and general grime. When it goes, the fabric wets out. This is the normal, expected failure, and it is exactly what reproofing renews.

Membrane failure or delamination (not fixable). Underneath the face fabric is the waterproof membrane. If that membrane delaminates, peels away from the fabric, cracks, or the taped seams lift, the jacket genuinely leaks. The giveaway is water getting through even in spots where the outside is still beading, or leaks tracking along seams. No amount of proofer will fix this. A proofer treats the surface; it cannot rebuild a membrane or re-tape a seam.

So before you spend anything, work out which one you have. If it wets out but doesn't leak, reproofing is the answer. If it leaks despite beading, or the inner face is flaking and peeling, the jacket is at the end of its life, and it may be worth checking the current deals on a replacement or our best waterproof jackets guide before you spend on proofer that cannot save it.

Step 1: wash it first

Reproofing a dirty jacket is a waste of proofer. This is the step people skip, and it is the one that makes the biggest difference.

Two things stop a proofer working. First, ground-in dirt, oils and salt physically block the DWR and stop water beading, so a good clean alone often revives an older finish before you even reach for the proofer. Second, and this is the important one, ordinary washing detergent is the enemy of a waterproof. Standard detergents leave behind residues that are designed to attract and hold water, the exact opposite of what you want, and they actively counteract the water-repellent coating.

The fix is a technical cleaner such as Nikwax Tech Wash, which lifts dirt without leaving those water-attracting residues behind. For most people the sensible buy is the Nikwax Tech Wash and TX.Direct twin pack, which pairs the cleaner with the wash-in proofer in one box and works out cheaper than buying them separately.

To wash it:

• Clean out the detergent drawer or run a rinse cycle first, so no ordinary detergent contaminates the wash.
• Fasten all zips and close the Velcro so the coating goes where it is needed.
• Add the tech wash to the detergent drawer at the dose on the bottle and run a warm cycle. Never use fabric softener.
• Do not tumble dry yet if you are going to use a wash-in proofer, because that goes on while the jacket is still damp.

Wash-in vs spray-on: which to choose

Both put a fresh water-repellent finish on the fabric. The difference is how, and where.

Wash-in proofer goes in the machine and coats the entire garment evenly, inside and out. It is the easiest, most thorough option for a plain waterproof shell, and it gets into every panel without you having to aim. The catch is that it coats everything, so it is not the one to use on a jacket with a soft wicking liner or an insulated lining you want to keep absorbent against your skin.

Spray-on proofer is applied by hand to the outer face only. That makes it the better choice in two cases: when you want to target the high-wear zones that lose their DWR first (shoulders under a pack, cuffs, the hood, and anywhere the rucksack straps rub), and when the jacket has a wicking or insulated liner you specifically do not want to coat.

For a straightforward hardshell, wash-in is the path of least effort. For a lined jacket, a softshell, or a targeted top-up between full treatments, reach for the spray-on.

Wash-in reproofing, step by step

Do this straight after the tech wash, while the jacket is clean and still damp.

1. Make sure the jacket is clean and wet, not tumble-dried. Wash-in proofer bonds best to a damp, freshly cleaned garment.
2. Empty the detergent drawer again so there is no residue.
3. Add the wash-in proofer to the detergent dispenser at the dose on the bottle. As a rough guide, Nikwax TX.Direct suggests around 200ml for up to two jackets in a front-loading machine, but always follow the label for your machine.
4. Run a warm, low-spin cycle. No fabric softener, no ordinary detergent.
5. Dry it by air drying or a low tumble dry (see the reactivating section below).

Once dry, run the water test again. It should bead cleanly. If one or two high-wear patches are still slow to bead, hit them with the spray-on rather than washing the whole thing again.

Spray-on reproofing, step by step

Spray-on is the tool for targeting the zones that wear first, or for jackets you don't want to coat inside.

1. Clean the jacket first, exactly as above, and leave it damp. A water-based spray follows the moisture into the fibres, so a clean, wet surface takes it best.
2. Lay it flat or hang it somewhere you don't mind overspray.
3. Spray an even coat onto the outer face from around 15cm away, concentrating on the shoulders, upper back, hood and cuffs, the pack-strap and high-abrasion areas that lose their DWR soonest.
4. Wipe off any excess with a damp cloth after a couple of minutes so it dries evenly without patches.
5. Let the finish develop. Modern PFAS-free Nikwax proofers develop their water repellency on air drying and do not need heat to work.

Reactivating the DWR

Heat is where there is a genuine, useful distinction to understand.

A factory-applied DWR (the treatment your jacket came with, such as the finish on a GORE-TEX shell) can often be revived with gentle heat before it is fully worn out. A low tumble dry, or a cool iron passed over a dry jacket through a tea towel or thin cloth, redistributes and reactivates the existing coating so it beads again. Only do this if the care label allows it, keep the iron cool, and never let it touch the fabric directly.

Nikwax proofers are different. Because they are PFAS-free and water-based, they develop their repellency simply on air drying and do not require heat to activate. A low tumble dry is fine and can help, but it is not essential with these products. So if you have just applied TX.Direct, you can air dry it and it will still work.

In short: use gentle heat to squeeze more life out of the original finish, but do not assume you need it after applying a Nikwax proofer.

How often should you reproof?

Reproof when the jacket tells you to, which is when it starts wetting out rather than beading. There is no fixed calendar for it.

Cleaning is more frequent than reproofing. As a rule of thumb, Nikwax suggests you can clean a garment with Tech Wash several times (roughly three to five washes) before the water repellency needs renewing with a fresh proofer. A clean jacket beads far better than a dirty one, so regular washing extends the gap between full reproofs.

For most UK hikers putting in regular miles, that works out to reproofing once or twice a season. Someone out most weekends in a wet Dorset winter, with a pack constantly abrading the shoulders, will need it more often than an occasional dog-walker. Let the water test decide, not the date.

Storing a waterproof over summer

If the shell is going away for the warmer months, put it away in good shape and it will be ready when the weather turns.

• Wash it before you store it. Salt, sweat and grime left in the fabric over summer degrade the coating and can leave a musty smell. Clean it with tech wash first.
• Make sure it is bone dry. Storing a damp shell invites mildew, which can stain and smell.
• Hang it, don't cram it. Long-term compression in a stuff sack can crease and stress the membrane and taped seams. Hang it loose on a wide hanger somewhere cool and dry, out of direct sun.
• Reproof at the start of the season, not the end, so the fresh finish is on the jacket when you need it. Do the water test on the first proper wet walk and treat it then if it wets out.

A waterproof is the outer layer of a system, so it is worth checking the rest of your kit at the same time. The same wash-in proofer does your waterproof overtrousers at the same time, one wash covers both. And if you are pulling everything out ahead of the colder months, the autumn and winter layering guide covers how the shell works with what you wear underneath.

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