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How to Keep Your Backpacking Gear Dry with Trash Compactor Bags

Line your Backpack with a Trash Compactor Bag
Line your Backpack with a Trash Compactor Bag

The first thing I do when I pack my backpack is to line the inside with a thick trash compactor garbage bag, like the kind you can buy in a supermarket. These plastic bags are very tough, last a long time, and are an excellent defense against rain and wet ground. I’ve been using this technique to keep my gear dry for years in all kinds of horrific weather, both for 3 season and winter hiking and backpacking.

Waterproof Backpacks

Most backpacks are not waterproof – even ones made with waterproof fabrics like Cuben Fiber and Dyneema. That’s because the stitching used to sew them together creates many tiny holes in the fabric that leak water unless the manufacturer seals them with seam tape (which is rare) or you touch them up with seam sealer. While you can buy a waterproof backpack, such as the Exped Torrent 50 or the ULA Epic, they’re usually 1-step up from rafting dry-bags and not as comfortable or functional as a regular 3 season backpack.

That’s where a trash compactor bag comes in. If the fabric of your backpack is reasonably waterproof, any water that leaks in at the seams will be stopped by the trash compactor bag before it gets to your gear. You can even pack your gear loose without stuff sacks and it will keep dry. You’ll get a lot more gear into a backpack by packing it loose like this, if space is an issue.

Using a trash compactor bag as a backpack liner also means that you can use regular stuff sacks instead of waterproof roll-top ones to pack your gear. This can save you a lot of money since waterproof stuff sacks have a limited life span before they fall apart – 2 years for me.

Backpack Rain Covers

Backpack rain covers are primarily designed to prevent the fabric of your backpack from soaking up water when it rains, a holdover from the days when packs were make out fabrics that were not waterproof, but they do a piss poor job of keeping the gear inside your backpack dry. Internal condensation, leaky seams, and poor fit are all contributing factors and a lot of hikers don’t even bother with them.

The Best Backpack Liners

I’ve experimented with many different backpack liners over the years ranging from black plastic garbage bags to the ultralight plastic backpack liners that Gossamer Gear sells. But when it comes to convenience and longevity, a trash compactor bag lasts the longest and is very easy to repair with duct tape if it’s punctured or torn. The white color also makes it a lot easier to see the contents of your backpack and they cost less than $1 per bag.

Sometimes the best backpacking gear isn’t backpacking gear at all.

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  1. I’ve been using the same trash compactor bag for over a year now as a liner. I just got back from New Zealand and its still holding up great. I have a cuben fiber liner, but I prefer the trash compactor bag.

  2. I have heard of this and read a couple short paragraphs on it but this report is comprehensive of alternatives, best options, maintenance and proofed advantages! I’m sold!!!! Thanks Philip!

  3. I agree, trash compactor bags is what I’ve used for years…
    They’re very durable and easy to replace…
    Take Care

  4. I agree with using trash compactor bags. I find they last for a couple months of daily use before they need replacement.

  5. I always pack one of these – either for the purpose mentioned or sitting on wet ground or wearing if it gets really cold and/or wet. A cheap, light way to cover a lot of issues.

  6. You’re so right, waterproof stuff sacks don’t last very long, and thy’re quite expansive! I’ve been using the garbage bag technique for a long time, but I never tried the particular trash compactor bags…. do you think they make a real difference? Thanks..

  7. The only compactor bags I can find here are “fresh scent”. The thought of having all of my gear feel like some marketing guy’s idea of what the outdoors smells like is bizarre and I’m rambling. Are there unscented bags?

  8. Been going this route for years. Simple, effective, inexpensive.

  9. I couldn’t find any unscented bags in local markets (east side of Portland, OR). The supermarket brands and Wallyworld bags were all scented. I’m concerned about the scent attracting varmints (inluding bears). Besides, the scent repels me!

    I’ve since been told that brand name trash compactor bags are generally unscented and can be found at hardware stores rather than supermarkets. I haven’t tried this yet.

    • Been down in the Everglades five weeks ago, and all I could find in the store there was the scented (yucky lemon) variety. Since there ain’t all that many bears down near the shore, and heavy rain was in the forecast, I went with it nonetheless …. and quickly found out that the raccoons loved my trash bag liner more than even my food stash. Your concern is definitely valid – compactor bags make great backpack liners, but do NOT use the strawberry piña colada varieties if you want your liner to survive the first night :)

  10. I hiked the entire AT with 2 compactor bags. I only switched them out because I could, not because I needed to. This is the best system to keep gear dry. Hands down. My gear was never wet INSIDE my pack. Also works good to section off wet/dry sections in your pack. It doesn’t feel right to pack my bag anymore without one of these. Lifetime supply of these bags is about $7.

  11. Are these not washable? By that I mean if the only alternative you can find are scented, is it not possible to buy them in advance and wash the scent material off prior to the trip? Or, perhaps even re-scent it with something like a mild bleach/water mix? Or some other scent less attractive and more repulsive to wild life?

    • I used the scented ones as I couldn’t find any others. I just washed with soap and water and air dried in my garage for a few days and I couldn’t detect the scent anymore. Now, that’s not to say another mammal with more sensitive olfactory equipment can’t but I’m betting it will just keep fading over time.

  12. Trash compactor bags are great, but if you can’t find the unscented kind, go to any hardware store and grab some contractor trash bags. They’re similarly thick, durable, and made to hold heavy and sometimes sharp items without breaking. From my experience, they’re usually located up front near the register as they are a contractor go-to item.

  13. So, no scented bags. I’ve also worried about not using a pack cover. I seems to me that a wet pack would be heavier and a bit of a mess to deal with in camp… I’m on the fence. I have a 2 oz. sil-nylon pack cover that has worked very well, I’m not sure that my GG Virga pack could absorb 2 oz. of water… change is hard!

    • If you’re comfortable with it, why change? What’s 2 oz.? It might not be working as well as you think though. How often do you walk in heavy rain for hours at a time….

  14. I’ve used normal black garbage bags before. I’ll have to give the trash compactor bag a try sometime it sounds like everyone has had great luck with it, thanks for the wonderful tip! I love the DIY tips and tricks for backpacking as well as the tips on using cheap alternatives to equipment marketed towards outdoor usage. Great way to save money.

  15. I couldn’t find trash compactor bags at the store I checked and used contractor bags. Those things are TOUGH! Unfortunately, I bought them too large but I’m using them up and will make another search for unscented trash compactor bags or small contractor ones.

  16. HI – whats the best way to secure the top? and what does 1 of these weigh? Thanks…!

  17. I used trash compactor bags for a while, now I’m using turkey roasting bags. Smaller, lighter, totally transparent, I use just one for my sleeping bag, most everything else in my pack can stand getting damp.

  18. I’ve been using autoclave bags that you use for sterilizing things in an autoclave.A little bit thicker and darn tuff.They are smaller so I seperate items such as clothes in one and sleeping stuff in another and are see thru so you can see what you need.Find a friend who works in med,dental or lab to hook ya up for free!

  19. We actually did this in the army. Trash bags are easily available and cheap. we will even do a double layer, especially when we need to do a river crossing.

    Great for going to the beach as well, swimwear and wet clothes goes into the trash bag and gets stowed into the gymbag.

  20. I have used a TC bag for canyoneering. Many swims with my backpack on, and completely dry inside. Just secured by tying. Also held air for flotation (I had a CCF pad, too).

    • your comment answered some questions for me, thank you! I’ve been wondering if this technique would be effective for river crossings, which seem like they might pose more problems to cooking and hydration gear than rain would, given the potential for contamination. crossings are also something a pack cover couldn’t help with regardless. i suspected the flotation factor might be helpful for that purpose too. i do wonder how much heavier the pack would get after absorbing water, especially in padded areas, and whether that could induce chaffing.

      • No more than a good soaking rain. Most river crossings on hiking trails are less dramatic than they sound. Unless you try to cross during a flood. The same it’s just best to wait for the water level to drop.

  21. I was looking for bags myself. I’d prefer the thick 3mil bags but the smallest denomination is 32 gal. Compactor bags, though, are a nice 18gal and 2mil thick. For comparison, typical kitchen waste bags are 0.87 to 1.1mil.

  22. Compactor bags seem to have a magnetic attraction to dirt. I use a PDW (Pretty Darn Waterproof) stuff sack (3oz.) that doesn’t have that problem.

  23. This is the best info I’ve found on the subject of trash compactor bags being used as pack liners. I had been using the XXX-large ziploc bags but these may be a lighter and more durable option. Great!

  24. As a foreigner I have to ask. What exactly is the difference between a trash bag and a trash compactor bag? Would they be available in continental Europe? I am also wondering how you are storing your bags at night with this method. We have a tent just big enough to fit the two of us in, and therefore have been using (heavy bulky) rain covers to keep our packs safe at night. Don’t the bags (straps mainly) completely soak and become very heavy from dew?

    • Compactor bags are heavy duty and made to have trashed mashed under pressure whereas garbage bags, even the “heavy duty” type, not nearly as rugged or durable,

    • Compactor bags are thicker than a standard bin liner being from 2.0 mil to 2.5 mil thick (53-63.5µm) and are even more robust because they are meant as liners for a kitchen compactor. Yes, they’re available in Europe (look for 18-gallon compactor bags). At night cover your backpack with a 3 mil contractor clean-up bag – they’re virtually bomb proof.

  25. Bought 30 HDX brand at Home Depot for $10. 2.5 mil, 18 gallon, unscented.

  26. Probably a stupid question, but what do you do to close the bag? Twist tie? Fold it a few times?

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