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How to Waterproof a Backpack: 7 Simple Tips and Tricks

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You’re out on a backpacking trip in the mountains on a bluebird day when, all of a sudden, large ominous clouds roll in from nowhere. Your fantastic day in the hills quickly turns into a wet mess with a torrential downpour and heavy winds driving you back down below tree line. 

You had your rain jacket at the ready, so you stayed dry, but your pack didn’t fare as well. All of your gear and clothing is sopping wet, and you still have five more nights left in the backcountry. Now, you’re looking forward to a cold, wet night in your damp sleeping bag instead of a good night’s sleep.

If you’ve spent a lot of time in the mountains, chances are pretty high that you’ve been caught in this awful situation before. Thankfully, there are ways to avoid getting stuck with soaking wet gear ever again.

The answer? Waterproofing your backpack. By taking a few simple measures before you leave home, you can help keep your gear dry in the backcountry, regardless of the weather conditions. Unfortunately, there’s a lot of misinformation out there about the best way to waterproof your backpack, which is why we’ve put together this ultimate guide to keeping your gear dry in the mountains. Let’s get to it!

How to Waterproof a Backpack: 7 Tricks to Keep your Backpack Dry

A wet backpack is uncomfortable, annoying, and most importantly, avoidable. Here are 7 ways to ensure that your next backpacking trip doesn’t end up in a soggy mess.

1. Use a rain cover

For the vast majority of us, an unanticipated downpour is the main culprit behind our wet gear. While this might not be a huge problem for someone out on a day trip, a wet down sleeping bag can be a dangerous thing, especially on a cold night. Thus, many people choose to use rain covers or pack covers to keep their gear dry in their backpack.

A rain cover is essentially a thin piece of waterproof fabric (usually ripstop nylon) with an elastic band around the edges. All you have to do with your rain cover is slip over your pack when it starts to rain, and your gear will be protected from the elements.

Pack covers are extremely popular amongst day hikers and backpackers, alike, because they are relatively lightweight and only need to be used when it’s raining. In fact, many new packs, especially those from Osprey, come with built-in pack covers that stow away in a small pocket when not in use.

However, pack covers are well-known for blowing away in the wind, so you’ll want to make sure yours is attached to your pack in some way, shape, or form. Additionally, while a pack cover is useful in the rain, it won’t do much for you during a river crossing as a pack cover will just get ripped away. Plus, pack covers only protect the front of your backpack and don’t waterproof any of the areas around the back panel.


  • Lightweight and compact
  • Pretty effective at keeping your pack dry in the rain
  • Some new backpacks have small storage pockets for pack covers


  • Somewhat expensive
  • Can blow away in the wind
  • Not effective during a river crossing

2. Apply seam sealer

While seam sealer isn’t a waterproofing method in and of itself, it is a tool you can use to help increase the natural water-resistance of your backpack. Since most packs are made with durable, semi-water-resistant materials (such as heavy denier ripstop nylon) to begin with, seam seal helps boost this water-resistance by preventing raindrops from seeping in through the seams of the fabric.

Seam sealer is basically a glue that you add on to your backpack (or other gear, such as a tent) to help prevent water from making its way through the small holes created by the stitching in fabric. Seam sealer, also known as seam grip, can be applied to nearly any nylon fabric and can drastically improve the water-resistance of your pack.

However, seam grip on its own is not a waterproofing solution. Seam seal is best used in conjunction with another one of these methods as a second line of defense against water. Plus, even though seam sealer is good at its job, it’s not foolproof, and you’ll have to re-seam seal your pack every so often to keep it up to snuff.


  • A simple way to increase your pack’s natural water-resistance
  • Relatively inexpensive
  • Prevents water from leaking through the seams of your pack’s fabric


  • Not a true waterproofing method
  • Needs to be used in conjunction with another method
  • Will need to be replaced every once in a while

3. Utilize a dry bag

Dry bags have become more and more popular amongst hikers and backpackers in recent years, and for good reason. These stuff sacks are made with waterproof ripstop nylon that’s fully seam-taped and ready to protect your gear, even if it gets submerged in water. These days, dry bags come in nearly every shape and size you can imagine, with some as small as 2L and some as large as 110L.

When it comes to hiking and backpacking, most people find that 2L-30L dry bags are just right for their needs. However, while dry bags are great at keeping your gear dry, it’s important to note that packing everything into individual small dry bags does make packing a bit trickier, especially when you’re out for a few nights.

Thus, instead of relying on dry bags to keep everything in your pack dry, we recommend using a few of them to keep your most valuable pieces of gear (e.g., electronics, sleeping bags, and books) safe in any weather conditions. In fact, dry bags are best used in conjunction with another waterproofing method or just for protecting your most important pieces of gear.

The main drawbacks to dry bags, in addition to the difficulty they can pose for your packing efficiency, are that they are expensive and that they add weight to your pack. High-quality dry bags run the gamut from $10 – $50 each, so you’ll need to spend a pretty penny to keep all of your gear dry with this method.


  • Very effective at keeping gear dry
  • Great for smaller and more valuable pieces of gear


  • Expensive
  • Can make packing more difficult
  • Adds weight to your pack

4. Line the inside of your backpack

Perhaps the most effective waterproofing strategy in this guide, lining your pack with a reusable or disposable pack liner is a great way to keep your gear dry, even in the nastiest of weather. Reusable pack liners are basically over-sized dry bags designed to line the inside of your pack to provide an all-encompassing waterproof layer around your gear.

While reusable pack liners are available to fit a variety of different pack sizes, many people also opt to use heavy-duty garbage bags to line their packs. Compactor lawn refuse trash bags are thick, durable, lightweight, and waterproof, which means they’re a great option for anyone looking to keep all of their gear dry when hiking.

Plus, when you use a pack liner, you can specifically choose to keep wet gear (like your wet tent in the morning) on the outside of the pack liner, keeping the rest of your gear dry, regardless of the conditions. Oh, and if that wasn’t good enough, a pack liner is pretty much the only foolproof way to keep all of your gear dry during a river crossing.

The main downside to a pack liner is that you’ll need to be careful when packing your bag in the morning as you don’t want to rip or poke holes in your liner with any sharp pieces of gear. Other than that, pack liners are a pretty awesome way to keep your gear dry in the hills.


  • Very effective at keeping all of your gear dry
  • Reusable and one-time-use options available
  • Works during a river crossing
  • Can’t fly away
  • Lightweight


  • Need to be careful when packing a pack with a pack liner so you don’t rip it

5. Use Ziploc bags

Quick, simple, easy, and affordable, Ziploc bags have long been a mainstay of the dirtbag hiker that’s looking to keep some of their gear dry while hiking. Since Ziploc bags aren’t very large – at least when compared to the size of an expedition pack – they’re best used to keep specific pieces of gear dry in the mountains.

Many people use Ziploc bags to add a layer of waterproofing to their Kindle or to organize their clothing inside their pack. Ziploc bags (or a generic equivalent) are incredibly popular because they’re available pretty much anywhere in the world, so they’re a great last-minute addition to your pack. Plus, they’re incredibly cheap (especially when compared to some other options), so there’s no reason not to have a few when you’re in the backcountry.

However, Ziploc bags aren’t purpose-built for waterproofing your pack, so you can’t expect them to work perfectly every time. While a brand-new Ziploc bag is pretty effective at keeping your gear dry, it’s not going to be as good as a quality dry bag. Plus, Ziplocs are known to rip easily and can develop small holes (particularly around the edges) that can compromise their waterproof integrity.


  • Very affordable
  • Can be found in nearly every grocery store or supermarket
  • Lightweight
  • Great for an additional layer of waterproofing on electronics


  • Not truly waterproof
  • Can rip and tear easily
  • Not large enough for bigger pieces of gear

6. Carry stuff sacks

Stuff sacks have become more and more common in recent years as people look for ways to better organize their gear inside their packs. These days, stuff sacks are available in pretty much any shape or size you can possibly imagine, so they’re incredibly popular among backpackers.

That being said, while most stuff sacks aren’t designed to be waterproof, the vast majority of them are made from ripstop nylon, which means they can provide some semblance of water-resistance to your gear. Thus, while we wouldn’t use them to submerge an important piece of gear, they are a cheap and easy solution that can help bolster your pack’s water-resistance when used properly.


  • Not designed to be waterproof
  • Can add some water-resistance to gear
  • Affordable
  • Available in many sizes

7. Apply waterproof Spray/treatment

Many companies, such as Nikwax, now make sprays and treatments that can be used to increase the waterproofness of specific pieces of gear, such as tents, rain jackets, and backpacks. These sprays don’t actually make gear waterproof; however, they simply add a layer of DWR (durable water repellent) that forces water to bead off of fabric instead of seeping through.

If your pack is made of ripstop nylon (most are), you can probably use a waterproofing spray to add a layer of DWR to the fabric and help keep your gear a bit drier in light rain. While this method isn’t sufficient on its own, waterproofing sprays, when combined with seam seal and other methods can help increase the overall waterproofness of your pack.


  • Relatively inexpensive
  • Encourages water to bead off of a pack instead of seeping through
  • Simple to apply


  • Not a true waterproofing method on its own
  • Needs to be used in conjunction with other solutions


Ultimately, there is no one single way to waterproof a pack. Instead, it’s important that you find the pack waterproofing system that works best for your needs so you can spend less time worrying about your gear getting wet and more time enjoying the great outdoors. Happy trails!

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