Waterproof vs Water-Resistant Backpacks? What is The Difference?

It’s mighty annoying to get caught in the rain on your way to work, isn’t it? What's worse is that your belongings could be wet, and if you have a laptop in your backpack you’re doomed. This is the reason why most people look for a water-resistant backpack now. 

And then they come online to search for their ideal backpack. Greeting them are thousands of options, but the thing is, some say they are water-resistant backpack, then some say they are waterproof backpack. What now?

At this point, many would start to feel a little baffled. What exactly does each of the two do? Which one do I even need? Worry not! We’re here to offer assistance. We’ll offer explanations, comparisons, and further information for you. So stay tuned!

What’s the fundamental difference?

Fundamentally, the difference actually lies partly in their names themselves. A water-resistant backpack only resists the water, which means at a certain point, water will be able to break through. A waterproof backpack is, however, completely impervious to any amount of water assault, meaning water will never go through.

That’s, in a way, an oversimplification of the gist of things. In actuality, there are various degrees of water-resistance and water-proofness that are designed for commercial purposes. So what are they, how do they function?

Water-resistant bags

They are indeed water resistant, but how much water can they repel and for how long, those are some major concerns. Some backpacks can come really close to being a waterproof bag, but they are still just a water-resistant one.

Material

Materials for water-resistant backpacks are common materials used in all kinds of bags, such as nylon, cotton, other plastic materials, etc. In and of themselves they don’t repel water. Manufacturers manage to produce them in a way so that they become “water-resistant”.

Some of these fabrics that are so-called “water-resistant” are actually just normal fabric, but they are woven with better production technology, allowing them to be much tighter. Still, no matter how tight your fabric might be, woven fabrics will always be just fabrics, in that there will be tiny holes between threads or batches of threads, where water droplets under the right condition (maybe a bit of pressure, a downpour?) could still seep in.

To combat this, most manufactures will apply a coating over the fabric, such as polyurethane (PU), polyvinyl chloride (PVC), or thermoplastic elastomers (TPE), and it’s this coating that is mostly responsible for repelling water, but it’s notorious for being washed away after a period of time.

Build

What a backpack is made of plays a huge role in its ability to repel water, but how it is constructed is equally important, if not more. No matter what kind of material is made up of, if the backpack isn’t made up to par, water can still ingress like nothing.

Some of the backpacks are marketed as “made with waterproof materials” but that could just be a marketing stunt. See, while they may truly be built from waterproof materials, that doesn’t mean water can’t find ways to infiltrate the backpack, for example, the zippers and the stitching.

Every zipper has openings in its teeth. As water runs on those teeth, there is a good chance that they will go through, and they will definitely go through if the backpack were to be submerged in water. Some bags will feature a splash guard or a fold-over to cover the zipper’s teeth, which helps, but they don’t really make your backpack waterproof.

You should also check if your bag is sewn or not. Oftentimes, this is the biggest giveaway to an only water-resistant backpack, as the needle holes and the stitching are gateways for water to enter. Silicon may be used to seal those holes, but they are not perfect nor permanent. Seam taping isn't as well, while stitches can fray.

Waterproof bags

Simple! Waterproof bags will not let any water in under any circumstances. That means, no matter if you’re using it in a downpour, or if you're submerging the entire thing under water for an extended amount of time, once you take it out and open your bag, everything inside will be bone dry.

Materials

Waterproof fabric (VX21 sailcloth, for instance) is constructed from multiple crisscross layers, effectively eliminating any holes through which moisture can breach through. To enhance any optimise the performance, i.e. the waterproofness, of their backpack, many backpack companies built their backpack from waterproof materials and coat a water-resistant layer on top of it.

Build

In order for a bag to be truly waterproof, every last bit of details on the exterior of the bag must be waterproof.

Having a waterproof material is one thing, how do you connect different pieces of such fabric into an actual bag is a completely different story. As we’ve mentioned above, sewing will not cut it. In order to combat this situation, people utilise a production technique called Ultrasonic Welding (or RF Welding). This is a high-end production technique, therefore products with these are still decently rare on the market.

In this technique, two pieces of cloth are fused together, essentially. In specific, two edges of two pieces of material (made from thermoplastic or with a thermoplastic coating) are carefully aligned and held together under pressure. It’s here when an Ultrasonic Welding machine will emit a high level of ultrasonic sound waves that impact the materials on a molecular level, effectively merging two pieces into one. Generally speaking, the area where the technique is applied is technically twice as thick as other areas, so it’s practically even stronger and more durable. Moreover, in the context of water-proofness, no holes or sewing or stitches, so no places for water to go in.

Zippers can also be designed to be waterproof. Albeit they may be tougher to pull, and they will require frequent maintenance and lubrication. They are also pretty hard to manufacture, so they are quite rare on the market.

Another factor the designers have to take into consideration upon crafting a waterproof bag is the possible ways for water to enter the bag. Water usually leaks into the bag through small leakages like zipper’s teeth and edges. To minimise the possible entries, designers must make some aesthetic and utility sacrifice.

So which kind of bag is meant for me?

By and large, some levels of water-resistance are preferable for most people, as nobody can tell on which day it will rain and there’s always a chance to get caught in one. Companies realise this and have largely incorporated water-resistance into their product and use them as a selling point to increase the overall value of their product. What that means is, even if you for whatever reason need none of the water-resistance features, and are fine with your belongings being bedraggled, then it’d still be hard to find a non-water-resistant bag.

So you’re essentially stuck with having to choose between a water-resistant and a waterproof bag. As for which to choose, it really depends on a multitude of reasons. Mostly, you’ll have to take into consideration what kind of conditions you’ll be using your bag in. Will it be a faint drizzle, or will it be a heavy downpour? Will you take it to a waterfall, or will you take it to a stream?

Price should also be taken into consideration too. The Ultrasonic Welding machines mentioned above are very expensive. The skilled technicians that are able to wield those machines are expensive. The selected few materials that can go into those machines are also expensive. And when everything that goes into a product is very expensive, you guessed it, the end product, the waterproof bag, is very expensive.

In most cases, you wouldn’t really need a straight up waterproof bag. Most water-resistant bags will perform just fine under most circumstances. Waterproof bags are specialised products, and they should be persevered for the people who go through heavy precipitation every day or the extreme adventures who engage in extreme sports.

Waterproof bag recommendation

We’ll pass on the water-resistant bag recommendations, as there are so many on the market. But the truly high-quality waterproof bag comes in few and far in between. So let’s have a look at some great options:

CabinZero ADV Dry Bag

CabinZero ADV Dry Bag is designed to combat all kinds of weather and keep your belongings dry at all times.

Coming in at either 11L or 30L, the ADV Dry Bag can cater to anyone’s needs. The 11L one can fit into a larger carrier and can still be reliable whenever you use it, while the 30L one is large enough to accompany anywhere. The bag features bungee cord on the front panel, allowing for great adjustability while keeping your stuff tightly and neatly packed. A thorough water-resistant coating with a dense fabric shell will ensure the safety of your belongings from water.

Final Verdict

Waterproof and water-resistant are two terms that are thrown around a lot when advertising for a backpack, and it’s so easy to misunderstand them. While water-resistant will prevent water from entering the bag at some level, it’s not guaranteed. Waterproof bags, however, are made so that absolutely no drop of water can get inside.

Most people should aim for a water-resistant bag, just in case of rainfall, but only the real sportspeople should invest heavily into a waterproof bag.