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 three-season and winter hiking and backpacking.
Most backpacks are not waterproof – even ones made with waterproof fabrics like Dyneema DCF and Xpac. 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 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.
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