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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.

Updated 2017.

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17 comments

  1. 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.

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

  3. 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.

  4. 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.

  5. 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!

  6. 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,

  7. 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).

    • 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.

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

  9. 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.

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

  11. Are these TC bags the correct size to use for the ‘bucket’ toilet when car camping? It must be cheaper than the ‘bucket’ recommended brand.

  12. I did a little web searching for bags so that I could get out of doing any real work today.

    Home Depot carries HDX (formerly Husky brand), unscented, 30 in a box, for about ten bucks. I’m going to get a box and line all the backpacks I have, which is too many! I do have different size packs I use for different conditions (weather, length of hike, whether or not I have to carry gear for others, etc.) and the grandkiddos use them as well.

    I succeeded in today’s avoid work expedition. Now I have to figure out how to elude productive labor tomorrow!

    • bought a box of them 2 yrs ago. got 28 left. (I only use 2 packs)

    • I use those from Home Depot, too. I go through them a little faster than others might because I use two at a time. One for sleeping gear at the bottom of my pack, the other for the rest of my gear in the top. One of them becomes night time storage in my tent and the other I use to inflate my sleeping pad.

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