A Deep Dive on Keeping Dry: Waterproof Tactical Gear

Rain, mud, sleet and standing water don't care what your job is. Here's how to understand waterproofing properly, decode the numbers on the label, and choose kit that keeps you dry when it counts.

We've all been there. Twenty minutes into a wet shift, water finds its way down your collar, your boots start to squelch, and every step gets a little heavier. Cold, wet kit doesn't just make you miserable. It saps body heat, rubs skin raw, weighs you down and drags your focus away from the job in hand.

The trouble is that "waterproof" is one of the most loosely used words in outdoor and tactical gear. A jacket that shrugs off a light shower can be soaked through in a proper downpour, and a boot that's fine for a quick walk can let you down on a long day in the wet. So what does waterproof actually mean, and how do you pick gear that lives up to it?

Let's start with the number that sits behind the claim.

Hydrostatic Head (HH): the number behind "waterproof"

Hydrostatic head, usually shortened to HH, is the standard way of measuring how waterproof a fabric really is. It's quoted in millimetres (mm), and it tells you how much water pressure the fabric can take before it starts to leak. Put simply, a fabric rated at 10,000mm HH can hold back a column of water 10 metres tall pressing down on it before the first drops get through.

How HH is tested
In the lab, a sample of fabric is clamped over a small chamber and water is pushed against it at a steady, rising pressure. The height of the water column when the third droplet appears on the far side is recorded as the fabric's HH rating. The most widely used method is ISO 811 (also seen as BS EN 20811). The higher the number, the more pressure the fabric can resist.

What the numbers mean in practice
Brands and retailers slice up the scale slightly differently, so treat these bands as a rule of thumb:

HH rating	What it means	Best suited to
Under 1,500mm	Water resistant only	Very light drizzle and brief showers
1,500mm	The usual minimum to call a fabric waterproof in the UK	Short, light rain
1,500–5,000mm	Waterproof in light to average rain	Everyday wear, urban patrols
5,000–10,000mm	Average to heavy rain	Long days outdoors, hiking, field use
10,000mm and above	Very heavy, sustained rain	Wet-weather duty, exposed and prolonged use

If you're working outdoors for hours at a time in British weather, a rating of 10,000mm or more is a sensible target. For quick dashes between the car and the building, you can get away with less.

Why HH isn't the whole story
A big HH number is a great starting point, but it only describes the fabric in a test rig, not the finished garment on your back. Keep these in mind:

Seams and zips can leak. A 20,000mm fabric will still let water in through untaped seams, open zips and worn cuffs.

Pressure matters, not just rain. Kneeling, sitting on wet ground or carrying a heavy pack puts far more pressure on the fabric than falling rain does.

Ratings fade. Dirt, abrasion and a worn water-repellent finish all reduce real-world performance over time.

Higher isn't always better. Very high HH fabrics can be stiffer, heavier and less breathable, which can leave you damp from sweat instead.

You may also see workwear rated to EN 343, which scores both waterproofness and breathability from 1 to 4. It's a handy cross-check, but wherever an actual mm figure is given, that's the number to look at.

Beyond HH: what else keeps you dry

Once you've checked the HH rating, these are the features that decide whether a garment or boot really performs in the wet:

Membrane or coating. Waterproof fabrics use either a laminated membrane, of which GORE-TEX is the best known, or a coating. Membranes are generally more breathable and more durable.

DWR finish. A durable water repellent treatment on the outer face makes rain bead up and roll off, so the fabric doesn't "wet out" and feel cold and clammy.

Seam taping. Every stitch hole is a potential leak, so fully taped or welded seams matter as much as the fabric itself.

Breathability. Measured separately, in grams of moisture per square metre per 24 hours (MVTR). If sweat can't escape, you'll get wet from the inside.

Zips, cuffs and hoods. Storm flaps, adjustable cuffs and a hood that sits well over a cap or helmet stop water finding a way in.

 

Waterproof gear at TacTree

So what should you actually wear? Here's where we'd start.

Boots: keep your feet dry first
Wet feet end a day faster than anything else. Our waterproof boots range covers 5.11, HAIX, LOWA, Magnum and VIKTOS, from lightweight patrol boots to heavy-duty safety footwear. Some models use a GORE-TEX membrane, including the HAIX Black Eagle Athletic 2.1 GTX and the LOWA Combat GTX MK2, while others, like the 5.11 A/T 8 WP and Magnum Viper Pro 8.0+ Leather WP, use a waterproof membrane liner.

Jackets: a proper shell for proper weather
For your upper body, a dedicated rain shell is the way to go. Take a look at the 5.11 Force Rainshell Jacket, the 5.11 Duty Rain Shell Jacket and the VIKTOS Range Trainer Waterproof Shell Jacket. Our full jackets and coats range also includes softer options for milder days.

Small kit: keep the essentials dry
Phones, tablets and paperwork don't survive a soaking. The aLOKSAK range of waterproof, dustproof and airtight bags is a cheap and simple way to protect them, and they slip into any pack or pocket.

Not sure what HH rating or features you need for your job or activity? Our in-house experts are happy to help you find the right fit. Get in touch and we'll point you in the right direction.

 

How to look after your waterproofs

Even the best waterproof gear won't last if you neglect it. Dirt, abrasion and age all wear down the protection, so a little care goes a long way:

Clean it regularly. Dirt and body oils clog the fabric and break down the water-repellent finish. Wash with a technical cleaner, not standard detergent or fabric softener.

Reactivate the finish. A short tumble dry on low heat, if the care label allows it, often revives the DWR.

Reproof when water stops beading. Once rain soaks into the outer fabric instead of rolling off, apply a wash-in or spray-on proofer.

Look after your boots. Clean off mud, let them dry naturally away from direct heat, and follow our boot care guide.

Store it dry. Never pack wet kit away, or you'll be reaching for damp, smelly gear next time.

Stay dry, stay ready

Waterproofing isn't just a number on a label. The right HH rating, sealed seams, a breathable membrane and a bit of aftercare all work together to keep you comfortable and focused, whatever the weather throws at you. Browse our full range of waterproof kit and gear up for the wet.