The complete guide to waterproof equestrian coat ratings and construction

Walk into almost any tack shop or browse online and you'll see jackets described as waterproof, highly waterproof or stormproof.

But what do those words actually mean?

The truth is that "waterproof" isn't a regulated marketing term. A jacket can legally be described as waterproof without telling you how waterproof it really is.

At EQUIDRY, we believe riders deserve more than vague claims. We exist to create the best waterproof coats and jackets for horse riders, equestrians and anyone who spends their time outdoors, using science, innovation and real-world testing to deliver waterproof performance you can rely on.

Every performance fabric we use is independently laboratory tested by Intertek or SGS, the world's leading testing organisations, to verify key performance standards including waterproofness, breathability, strength and durability.

But laboratory testing is only where the process begins.

Before any garment reaches production, it spends months being worn, ridden in and put through its paces by our team in real-world equestrian conditions. From long days in the saddle and wet winter yard work to dog walks, competitions and everyday riding. Every design is refined through extensive field testing to ensure it performs exactly as we claim because the best test isn't just in the laboratory, it’s how a garment performs when real riders depend on it.

Only once we're confident a garment performs in the real world do we put it into production. 

When you're looking for the best waterproof coat for riding, the labels can feel like another language: 20K, hydrostatic head, breathability, taped seams, DWR. What actually keeps you dry through a long, wet day with the horses?

The answer is a complete waterproof system. Fabric matters, but so do the seams, the openings, the shape of the coat and what happens when you start to move. Here's how to read the numbers and choose the right EQUIDRY for the conditions you face.

If you've ever compared two "waterproof" coats side by side and wondered why one keeps you bone dry after four hours at the yard while the other lets water through at the seams within twenty minutes, the answer is fabric science and specifically, three numbers most shoppers never learn to read: hydrostatic head, breathability, and construction.

This guide explains exactly what makes an EQUIDRY coat waterproof, how that's measured in a lab, where EQUIDRY’S technologies sit against the wider outdoor and equestrian market, and how we actually build a coat to survive a British winter on the yard rather than a weekend hike.

What does a waterproof rating mean?

"Waterproof" isn't a legally protected term, which is why it gets used loosely. In the UK, a fabric only needs a hydrostatic head of 1,500mm to be labelled waterproof, a figure that would let water through very quickly!

That's the gap this guide closes: the difference between technically waterproof and actually waterproof in the conditions you're using the coat for. 

A waterproof rating usually refers to a fabric's hydrostatic head: the industry-standard measure of waterproofness, the water pressure it can resist in a laboratory test before water starts to penetrate it. The result is given in millimetres. A 20,000mm rating, often shortened to 20K, means the fabric resisted pressure equivalent to a 20,000mm column of water under the specified test conditions. 

A sample of fabric is clamped over a chamber, and water pressure is increased steadily against it until moisture penetrates the material. The height of the water column the fabric withstood at that point, measured in millimetres is the hydrostatic head rating. 

Our waterproof fabric ratings are independently tested by SGS and Intertek, depending on the range, so the figures we publish are backed by external laboratory results.

Generally speaking, 20,000mm or higher is considered a premium, top-tier rating across the wider outdoor industry, and it's the benchmark most technical hiking and mountaineering shells are built to. It's also the benchmark we build almost every EQUIDRY coat range to, for a reason that's specific to equestrian life rather than hillwalking.

You'll see riding jackets advertised at 5K, 10K, 20K and higher. Higher figures indicate greater resistance to water pressure in that test, but there is no single rating that tells the whole story of how a finished coat will perform in rain. A high-rated fabric still needs carefully constructed seams and weather-protective details. Equally, a higher number does not automatically make a coat warmer or more comfortable.

For our waterproof equestrian ranges, we use 20K fabrics across most of our technologies. Our insulated THERMASHIELD™ puffers have an 8,000mm rating rather than 20,000mm: this range prioritises heat-bonded insulation for genuine cold-weather warmth, using welded rather than stitched chambers specifically to avoid the thousands of needle holes that stitched quilting creates. At 8,000mm, it comfortably exceeds the threshold needed for prolonged rain exposure while carrying enough insulation to perform in genuinely cold conditions - the trade-off is a deliberate design choice, not a shortfall.

Hydrostatic Head	General Performance Level	Typical Use
Under 1,500mm	Water-resistant only	Showerproof, not genuinely waterproof
1,500–4,000mm	Light protection	Short exposure, casual showers
5,000–9,000mm	Moderate protection	Everyday wear, moderate rain
10,000–19,000mm	High protection	Sustained rain, exposed conditions, kneeling/leaning pressure
20,000mm+	Premium protection	Prolonged, driving rain and continuous outdoor exposure

How are waterproof ratings actually tested?

We use independent laboratory testing to check the properties of our technical fabrics. These results tell us important things about a material, but a fabric test is not the same as a rain test of a finished coat. The fit, seams, zips, hood, care and wear all affect real-life performance. That's why we explain the design as well as publishing the ratings.

Hydrostatic head measures resistance to water pressure and generally a HH test runs like this:

Sample preparation — a fabric sample is cut to a standard size and clamped face-down over a sealed water chamber, with the edges sealed to prevent any false leaks.

Controlled pressure increase — water is pushed against the underside of the fabric at a steady, controlled rate, gradually increasing the pressure.

Penetration point recorded — the test continues until moisture is visibly seeping through the top surface; the water height at that exact moment is recorded in millimetres as the hydrostatic head rating.

The same fabric is typically also tested for breathability (moisture vapour transmission), colour fastness, seam strength, tear strength and abrasion resistance (Martindale cycles). The Martindale abrasion test repeatedly rubs a fabric sample to assess resistance to wear; EQUIDRY fabrics have been tested beyond 100,000 cycles to ensure your coat lasts season after season.

We'll cover durability and breathability testing in detail in the next guide in this series.

How we construct a waterproof EQUIDRY?

The tests above tell you about the face fabric. What really determines whether a coat stays waterproof in the field is how that fabric is constructed and finished. Every genuinely waterproof coat, ours included, relies on the same core components working together:

1. An outer fabric chosen for the job

The outer, or face fabric, is the first part of the coat exposed to rain and abrasion. We use different fabrics for different jobs: the tough nylon of EQUIGUARD® for our oversized coats, ripstop polyester in RIPSHIELD® and DURATECH™, and lighter polyester fabrics in STORMLITE™ shells. Abrasion and tear resistance matter around horses!

2. A waterproof barrier beneath the surface

The waterproof membrane or barrier sits behind the face fabric is where the real hydrostatic head performance comes from. Typically a TPU (thermoplastic polyurethane) coating or membrane is bonded to the inside of the outer fabric. This is the layer that physically stops water penetrating while, critically, allowing moisture vapour from perspiration to escape outward. Our EQUIDRY technologies use a TPU barrier. Waterproof performance comes from this construction, rather than from visible water beading alone.

Our Varsha and Nimbus use a three-layer shell construction with a protective inner backing rather than a loose fabric lining. Other styles use separate linings or insulation to give a different feel and level of warmth. The number of layers doesn't tell you how warm a coat is: a three-layer shell can be light enough for a mild day.

3. Seams designed to resist leaks

Sewing a coat makes tiny holes along its seams. That's why our waterproof technologies use taped seams: tape is applied over the stitching on the inside to help prevent water entering through those holes. A strong waterproof fabric without protected seams would leave a major weak point in the finished garment.

4. Windproof construction

Wind doesn't just make a coat feel colder; it drives rain sideways and forces moisture into weak points such as seams or through low density fabrics. Rain can also find its way in through a poorly closed front, an open pocket, a loose cuff or a gap at the neckline. Features such as waterproof zips, adjustable hoods and storm guards are a vital part of each EQUIDRY. Check the individual product page for the details of your chosen style, and fasten it correctly when you need maximum protection.

Coverage changes how dry you feel too. Our oversized coats are cut to shelter more of you and allow room for a body protector, while fitted jackets, trousers and the All-in-One offer different ways to protect the areas most exposed when you ride.

5. Lining

The lining is chosen for comfort, warmth or feel rather than waterproofing itself. Because different garments serve different purposes, EQUIDRY uses several distinct lining types across its ranges rather than a single default:

• Mesh — maximum airflow, used where breathability and freedom of movement matter more than warmth (e.g. milder-weather and higher-activity garments)
• Thin microfleece — lightweight, everyday warmth without bulk
• Thick Sherpa fleece — maximum insulation for the coldest conditions
• Bonded, air-filled chambers — used in place of a traditional lining in insulated garments like THERMASHIELD™, where heat-bonded chambers trap still air for warmth while avoiding the needle holes stitched quilting creates
• Warm padding — synthetic insulation used where dedicated thermal warmth is needed, independent of the waterproof membrane itself
• Sateen-like polyester — a smooth, soft-to-skin finish used where next-to-skin comfort is the priority
• No separate lining — some constructions, like Varsha, skip an internal lining altogether, relying on the 3-layer construction itself (face fabric, membrane, bonded inner layer) for structure and next-to-skin feel, keeping the garment lighter and less bulky

The lining doesn't affect the waterproof rating, that’s determined entirely by the membrane and outer construction but it's what determines how a coat actually feels to wear for hours at a time, which is just as important for all-day equestrian use.

6. A finish that helps the face fabric shed water

A durable water repellent finish (DWR) surface treatment is applied to the outer fabric that causes water to bead and roll off rather than soak in. Without DWR, even a fabric with an excellent membrane will "wet out”. The outer face saturates, blocks airflow, and the coat starts to feel cold and heavy even though the membrane underneath is still doing its job. All EQUIDRY technologies use a fluorocarbon-free DWR, avoiding the PFC chemicals that older durable water repellents relied on.

THERMASHIELD™ takes a further approach to it’s construction: its insulated puffers use heat-bonded chambers instead of conventional stitched quilting across the chambers, reducing needle holes through the outer surface.

EQUIDRY waterproof technologies compared

Rather than building one fabric and stretching it across every product, we've engineered a different technology for each purpose but held every one of them to independent testing against the same internationally recognised standards.

Technology	Waterproof rating	Breathability	What makes it different	Styles
EQUIGUARD®	20,000mm+	14,000g/m²/24hr	Durable nylon outer; choice of linings in the oversized coats	Evolution, Original, Shortie, All-in-One, over trousers; also dog coats and exercise sheets
STORMLITE™	20,000mm+	Up to 50,000g/m²/24hr	Lightweight shell protection and layering versatility	Varsha, Nimbus, Frontier, Verbier
RIPSHIELD™	20,000mm+	34,000g/m²/24hr	Ripstop polyester for strength and waterproof performance	Freya jacket, Freya trousers, Aura
DURATECH™	20,000mm+	Over 10,000g/m²/24hr	Brushed ripstop outer focused on wear resistance	Nevada
PROSHIELD™	20,000mm+	15,000g/m²/24hr	Fitted styles with lightweight insulation	Iris, Bronte
WEATHERFLEX™	20,000mm	Approx. 22,000g/m²/24hr	Flexible, protective construction for the Storm Smock	Storm Smock
THERMASHIELD™	8,000mm	Approx. 4,000g/m²/24hr	Waterproof, insulated puffers with heat-bonded chambers	Thora, Tor, Talia

Which waterproof coat should you choose?

20,000mm is the benchmark across most EQUIDRY waterproof ranges. When choosing a coat, also consider its construction, warmth, coverage and intended use.

If you're active in milder rain, start with a breathable  STORMLITE™ shell jacket such as Varsha, Nimbus or Frontier and add layers to suit the temperature. If you want generous coverage and a choice of warmth, explore the EQUIGUARD® oversized coats and their mesh, thin fleece or thick fleece options. For a closer silhouette, look at PROSHIELD™ or RIPSHIELD™. For cold, wet days, consider the insulated THERMASHIELD™ puffers. 

Waterproof rating and warmth are separate decisions. Our EQUIDRY Thermal Rating guide helps you compare how warm each style feels; our fit guide explains the difference between oversized, relaxed and tailored styles. Choose for the weather, your activity and the coverage you want, then compare the features of the individual garments.

How do you keep a waterproof coat performing?

Mud, body oils and repeated use can affect the outer finish and comfort. Follow the care label for your exact EQUIDRY style, clean it as instructed, and check its water repellency over time. If water stops beading and the outer wets out, care or reproofing may help restore the finish. A DWR treatment is part of the system; it cannot repair a damaged membrane, seam or zip.

The best waterproof equestrian coat is the one that keeps working through your day: protecting you from rain outside, helping manage moisture inside, and giving you the coverage and warmth you need around horses.