How Waterproof Are Tents?

With so many different types and models of tent on the market, it only stands to reason that the level of waterproofing tents offer covers a wide spectrum. In this post, we take a closer look at the degree of waterproofing you can expect from different tent models.

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Written by: | Reviewed by: Brian Conghalie
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Camping tents not only come in all shapes and sizes but also provide varying levels of protection against the elements.

But just how much protection does any tent provide, how is this measured, and how are we to know a highly waterproof model from a less waterproof model?

Below, we offer a short guide revealing just how waterproof tents are. Alternatively, if you want to re-waterproof your existing tent then check out our guide to the best tent waterproofing spray

Hydrostatic Head

The main metric used to measure the waterproof capacity of tents is hydrostatic head (HH). HH ratings are applied to products during lab testing in which an open-ended test tube is placed on top of the fabric and filled with water to apply water pressure to the surface of the fabric. The water volume (and, thus, pressure) is then steadily increased and the point at which the water passes through the fabric determines the fabric’s HH.

Hydrostatic head ratings are given in millimeters and commonly found on product specifications as follows: 10,000 HH or 10,000mm HH. Simply put, the higher the HH, the more waterproof a product’s fabric is.

Hydrostatic head in practice

In most countries, a HH rating of at least 1,000mm HH is required for any tent to be marketed as “waterproof.” In reality, however, tents with a 1k HH rating are capable of withstanding only the very lightest of short-lived showers.

The hydrostatic head rating of the rain flies on most three-season tents ranges from around 1,500mm to 2,500mm. Tents at the lower end of this scale can be prone to leakage after extended exposure to moderate rainfall but those around and above the 2k mark are usually capable of withstanding a combination of heavy rain and strong winds and, as such, are suitable for all but the most extreme conditions.

Tents with a HH rating in excess of 2,500mm fall into the proverbial “bombproof” category, meaning they are able to withstand heavy downpours, gale-force winds, and the added pressure of objects or bodies pressed against the fabric from the inside, something that can cause leakage in models with a lower HH rating. This HH rating is most commonly found in the fabric used on expedition and mountaineering tents.

In most cases, the floor used in any camping tent will have a much higher HH rating than the rainfly. This is because more pressure is applied on the flooring by the tent’s occupants and their gear, which increases the likelihood of groundwater seeping through the fabric. Consequently, most tent floors have HH ratings of over 2,000mm, with three-season models usually falling into the 3,000-4,000mm range and four-season models often scaling as high as 8,000mm.

While HH ratings give us an indication of how waterproof a tent’s fabric is, the fabric alone is not the only factor contributing to a tent’s overall waterproofness. Three other factors to look out for are the use or absence of a DWR coating, the seams, and the zippers.  

DWR Coatings

In addition to the PU coating or membrane that forms a tent’s main resistance against water, many rain flies (and some tent inners) are treated with a DWR (durable water-resistant) coating. In short, this coating causes water to bead up on the surface of the fabric and then roll off, thus reducing the chance of saturation.


The seams on a tent are one of its greatest points of potential weakness owing to the fact that they join two pieces of separate fabric and are pocked with hundreds of tiny holes where the fabric has been stitched together. As such, the most waterproof varieties of tent usually have seams that are double-stitched (to secure the bind of the two sheets of fabric) sealed (treated with a layer of hydrophobic glue or sealant to prevent leaks), or taped (lined with waterproof tape during manufacturing).


Another factor contributing to how well a tent will resist the elements is the protection provided around the zippers. A good tent will always have storm flaps—strips of fabric that fold over the zipper and are fastened with velcro to prevent rain from coming through the teeth of the zipper.

Last update on 2024-06-20 / Affiliate links / Images from Amazon Product Advertising API

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Kieran James Cunningham is a climber, mountaineer, and author who divides his time between the Italian Alps, the US, and his native Scotland.

He has climbed a handful of 6000ers in the Himalayas, 4000ers in the Alps, 14ers in the US, and loves nothing more than a good long-distance wander in the wilderness. He climbs when he should be writing, writes when he should be sleeping, has fun always.

Kieran has taught mountaineering, ice climbing, and single-pitch and multi-pitch rock climbing in a variety of contexts over the years and has led trekking and mountaineering expeditions in the Alps, Rockies, and UK. He is currently working towards qualifying as a Mountaineering and Climbing Instructor and International Mountain Leader.

Kieran’s book Climbing the Walls—an exploration of the mental health benefits of climbing, mountaineering, and the great outdoors—is scheduled for release by Simon & Schuster in April 2021.

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