How Do Dry Bags Work and Are They Totally Waterproof?

Last Updated on 28/02/2022

Are you wondering how do dry bags work and whether you should get one? Take a look at some of these common questions about dry bags (with answers). In this guide, you will learn more than you ever thought you would about how dry bags actually work.

How Do Dry Bags Work?

A dry bag is a purpose-built stuff sack that’s designed to keep the contents inside dry, even if the bag ends up in the water. It is made from waterproof material and has a roll-top closure which secures with a single buckle. By rolling the roll-top multiple times it creates an airtight seal which is helped by a thin strip of plastic on one side of the very top. The buckle then fastens together at the top which makes a loop and means it can easily be attached to your bag or kayak.

We have an Ultimate Guide to Dry Bags as well as a top 10 list for hiking dry bags and Kayak Dry Bags if you are interested in seeing some of what’s on offer,

How Do You Seal a Dry Bag?

Dry bag material is impermeable to water and 99 percent of the time will already be factory seam-sealed so it is important to understand how to close a dry bag properly and get a fully watertight seal.

Pack your items – be sure not to have any sharp objects pointing outwards and if you have any valuables or electronics I always like to wrap them in clothing for shock absorption.
Compress the items down as much as possible and where possible remove as much air as possible – always leave enough space to get at the very least three rolls of the top.
Line up the edges at the opening of the bag and neatly fold over three or more times – roll until you have no empty space left without stretching the fabric. You may find you still have lots of air in the bag when you do this but just repeat the previous step.
Bring the buckle clips together on the side you rolled up – this then secures the roll-top in place and also allows the drybag to be secured to things.

Do Dry Bags Work?

A high-quality dry bag that’s used properly does, indeed, work, but the full explanation is not that simple.

In fact, what this all comes down to is a question of the materials used to make the dry bag and the conditions the dry bag is being used in. While all well-maintained dry bags will work in the conditions that they were meant to work in, many people don’t realize that there are limitations to a dry bag’s effectiveness. Do dry bags work with a hole in them? No.

Indeed, while some dry bags are mean to protect your gear when it’s inside another dry bag or backpack, others are meant to be the first line of defense against being submerged in water. Unfortunately, the way that dry bags are marketed and sold these days does make it seem like they are all designed to protect your smartphone or camera if the bag falls into the water.

Dry bags kind of work…

The fact of the matter is, however, that this is just simply not true. While there certainly are dry bags and dry cases that can keep your electronics dry while submerged in water, these are actually quite rare – and quite expensive.

In fact, the majority of dry bags on the market today are thinner “lightweight” models made of seam-sealed nylon. Although these bags can keep your gear dry, they’re not exactly recommended as your only barrier between your belongings and the water.

Alternatively, the thicker, heavy-duty TPU-coated river dry bags are going to be your best bet as the outer layer of defense for keeping your gear dry. But, it’s always recommended that you double, or even triple bag your most important gear in a number of different dry bags, just in case one has a hole or starts to leak.

So, do dry bags really work? Well, yes, they do, so long as you’re using a particular dry bag for the situations it’s designed to be used in and nothing more – and so long as they don’t have any holes in them.

Are Dry Bags Waterproof?

As previously discussed, yes they are if made from waterproof materials with sealed seams and the person using it knows how to close a dry bag. With some dry bags claiming to be waterproof and others only water-resistant, how do you know which dry bags work best? Let’s have a look at the term in more detail.

What Does Waterproof Mean?

First and foremost, let’s discuss the meaning of the word “waterproof.” While this might sound like a word with an obvious definition, it turns out that the concept of being “waterproof” is much more complex than most people would imagine. In fact, there are many different meanings given to the word “waterproof,” depending on who is using the word and what they’re talking about. There are even standardized systems out there that are used to describe an object’s waterproofness.

Perhaps the most commonly used standardized waterproofing scale is the IP or “Ingress Protection” Rating system that’s used by the IEC for the rating of electrical equipment under the IEC 60529 standard. This might sound like a whole lot of mumbo jumbo, but basically, an IP score is a rating given to a product that describes how well it can prevent against (1) the intrusion of solids, like dust, and (2) the intrusion of liquids, such as water.

Every object reviewed under this system is given a rating, comprised of IP followed by two numbers, such as IP57, where the first number refers to protection against solids and the second against liquids. The higher the numbers, the more water and dust-tight the object. Anything with a rating of IP68 is dust-tight and submersible beyond 1m in depth.

Dry Bags Hydrostatic Heads

The IP system is standardized and clear cut, however, many fabric-based products (like drybags) will use millimeter ratings depending on how much water the fabric can resist based on a hydrostatic head test. For example:

0-1,500mm: Effective against drizzles
1,500mm-5,000mm: Effective against light to average rain
5,000mm-10,000mm: Effective against moderate rain
10,000+mm: Effective against heavy rain

However, this test, while commonly used for fabrics, does not tell us if a bag made of a given fabric is submersible like the IP rating system does. But, what does all this mean for you?

Well, basically it means we don’t really have a good standard by which to measure “waterproofness” in dry bags. Instead, we have to go with personal experience and an objective review of the materials used to make a particular dry bag.

So, if we assume that a dry bag is being used correctly (this means closing it according to the manufacturer’s instructions), we, unfortunately, can’t assume that a given dry bag is always going to keep your gear dry. Instead, we have to break down the category “dry bags” into smaller subsections.

Splashproof Dry Bags

Splashproof dry bags are basically the lower rung of the dry bag ladder. They’re made with ultra-light ripstop nylon that’s not meant to be submerged in any way, shape, or form. While these dry bags are often seam-taped and feature those snazzy roll-tops to make them look like a regular dry bag, they are really only good for acting as a second layer of protection for your gear from inside your pack or dry bag. They are not supposed to be used on their own in the water but are great lightweight little pieces of gear.

Water-Resistant Dry Bags

Moving slowly up the ladder, here, we get to the water-resistant dry bags. These puppies are made from thick, durable nylon that is seam-sealed. They usually have roll-top closures and are able to protect your gear from quick dunks in the water as well as heavy rain. But, we wouldn’t trust them on their own for extended submersion. Instead, they’re great inside a backpack or as a second layer of defense inside a larger dry bag.

Submergible Dry Bags

These are pretty much the best of the best when it comes to fabric dry bags. Submergible dry bags can survive a modest amount of time in the water because they’re made with super-tough TPU-laminated fabric that’s seam-sealed. However, even these dry bags aren’t made to be kept underwater at depth for an extended period of time. But, if you use them in conjunction with smaller dry bags, they can do a great job of keeping your gear dry if your raft or kayak flips.

The moral of the story? Basically, yes, dry bags are “waterproof” do work, so long as you keep them in good condition and understand their limitations. Would we use just one on its own for a kayaking trip? Definitely not. But, we would be conscientious about double and triple-bagging our most important gear and using the dry bags that are most appropriate for the conditions of our adventures.