How Waterproof is "Waterproof"? Houghton Country's Guide to Waterproof Ratings

We all know that venturing outside, whether it’s to walk the dog, care for or ride your horse, or run errands, in the depths or winter or on the wettest of autumn days can be testing to even the hardiest amongst us; we’ve all had days where we’ve been soaked through to our underwear, water dripping from your eyelashes and your clothing stuck to you! It may seem, however, that some hardy people always have a smile on their face regardless of how bad the rain or snow is, even appearing to enjoy a dog walk or hack out in the wettest of weather. So what’s their secret? As the saying goes there is no bad weather, only unsuitable clothing – and the key to enjoying time outside on the wettest days is to kit yourself out with appropriate waterproof clothing. 

Many garments designed for wear outdoors are described as waterproof. But did you know some are more waterproof than others? This guide outlines different waterproof ratings and what they mean, as well as breathability and technical features commonly found on waterproof garments, so you can choose the right waterproof jacket, coat or trousers to suit your needs.

Every waterproof garment has a waterproof rating up to 20,000mm. The higher the rating, the longer the garment will keep moisture out for; i.e. the heavier rain it can be worn in. Higher rated waterproof clothing also tends to come with superior breathability – especially desirable if you are wearing your waterproof layers to exercise in and need moisture to be able to escape.

These ratings are devised from a test called the Hydrostatic Head Test which involves a piece of the fabric in question being placed under a sealed tube of water for 24 hours. It is then measured how many mm of moisture the fabric can withstand before moisture penetrates the fabric. The level at which the moisture starts to seep through is the waterproof rating.

0-1500mm

These garments are usually labelled as “showerproof” or water-resistant, suitable for keeping you dry in very light rain. They would keep you dry in a short period of drizzle, but the lining would likely end up wet if you were to be out in drizzle or rain for a longer period.

1500-2000mm

These garments meet the British Standard for being waterproof and will keep moisture out during exposure to light rain. They are ideal for a quick dog walk, bringing the horses in out of the rain, getting to and from the stables to the field, or walking around town. One of these jackets or coats are ideal for popping on when you are unsure what the weather is going to do that day. A higher waterproof rating will however be required for prolonged exposure to rain or very heavy rain.

5000-10,000mm

A superior waterproof rating, these garments will keep the wet out in moderate to heavy rain. This higher rating also comes with enhanced breathability, which if you are engaging in physical activity such as running, cycling, schooling or jumping with your horse, will be beneficial. These garments will keep you dry during a shorter period in heavy rain, or a prolonged period in moderate rain. Due to their breathability they are usually comfortable as well as functional, ideal for riding in the rain, long walks in bad or unpredictable weather, or spectating at shows when the forecast isn’t great!

20,000mm

The highest waterproof rating, these garments are highly waterproof, keeping out heavy rain. If you are teaching in all weathers in outdoor arenas, know that you will be riding, walking or working in torrential rain, one of these jackets or coats would be a worthwhile investment. They are not only an ideal top layer for keeping any water out, but can also feature additional layers for warmth and more technology for breathability, such as underarm vents.  

It is not just the waterproof rating that is worth considering when looking to buy a waterproof coat, jacket or trousers. You may see other technical features listed in the descriptions and wonder if they are important or not. Taped seams are one of the most important features on a waterproof jacket or coat, as water can seep through stitching that has not been heat sealed. Garments with taped seams are chosen for prolonged exposure to heavy rain. Likewise, for total waterproofness, the zip should be waterproof, as moisture can seep in through the teeth of the zip. Elasticated, close-fitting cuffs also help to keep water out. Some items that claim to be waterproof repel water by benefitting from a waterproof coating, rather than the fabric itself being fully waterproof. These garments are water-resistant and are usually less expensive than fully waterproof ones, but they are likely to need reproofing. You may also look for multi-layers including a fleece lining to enhance comfort and breathability, as thin, 2-layer waterproof layers with a thin mesh inner can feel clammy and cold against the skin. The advantage of thinner waterproofs is however of course that they are easily and neatly packed away. When selecting the size of your new waterproof jacket, coat or trousers, consider whether you will want to layer up underneath for wear in cold weather, and size up accordingly.  

A 20,000mm waterproof coat or jacket promises to keep you dry in the worst of rain, so would be a sensible choice for long days spent outside in very heavy, constant rain. In an ideal world, every waterproof jacket would have this rating, but the truth is for many of us most of the time a lesser rated jacket will suffice. That said, if you know you will be enjoying outside pursuits or working outdoors whatever the weather, outerwear with a higher waterproof rating will be a worthwhile investment. 

Shop Women's Coats & Jackets and Trousers including waterproof trousers, Men's Coats & Jackets, and Children's Coats & Jackets. 

The product descriptions of each of our waterproof coats, jackets and trousers explain what makes them waterproof, so you can make an informed decision as to which one meets your needs the best. If you are still confused, feel welcome to contact our knowledgeable team on 01661 853110 for advice on our current stock of waterproof layers!