A garbage bag is one of the most cost-effective options as a pack liner or stuff sack. Although many trekking backpacks are made from water-repellent materials, moisture can still get inside during prolonged rain or when the backpack is placed on wet ground. A pack liner reliably protects all the gear inside the backpack from getting wet.
I tested several garbage bags, and one in particular proved to be especially suitable. This bag came from a discount store and cost only about €2 per pack. Each pack contains five bags, resulting in a very low price per unit.
The garbage bag is sturdier and thicker than typical household trash bags. The material feels robust and does not tear easily, even when pushing in clothing, a sleeping bag, or other equipment. This is important for trekking, as the bag is constantly under stress inside the backpack.
With a volume of 65 liters, the bag is large enough to be used as an inner liner for backpacks up to around 60 liters. The garbage bag is simply placed inside the empty backpack and then filled with gear. At the end, the top of the bag can be twisted or folded over to minimize water entry.
A major advantage of this solution is its low weight and cost. Specialized waterproof pack liners or stuff sacks made from outdoor materials are often significantly more expensive. However, a simple garbage bag serves the same purpose and keeps clothing, sleeping bags, and other equipment dry.
Additionally, a garbage bag has the advantage of being easy to replace. If it gets damaged during the trip, it can quickly be swapped out for a new one. Due to the low cost, it is also practical to carry several spare bags.
Pack Liner (e.g., garbage bag)
Advantages
- Very lightweight
- Very inexpensive
- Keeps gear dry
- Provides protection even on wet ground or snow
- Easy to replace
Disadvantages
- Backpack gets wet on the outside
- Can tear more easily
- Packing is slightly less convenient
Backpack rain cover
Advantages
- Backpack stays drier on the outside
- Quick to attach
- Partially protects gear attached to the outside
Disadvantages
- Does not provide complete waterproof protection
- Can slip or get lost in strong wind
- Water can enter through seams or openings
If you want to be on the safe side, you can use a garbage bag as a pack liner inside the backpack and additionally put a rain cover over the outside. This way, both the contents and the backpack itself are better protected from moisture.
For my trip to Nepal, I also used the thicker garbage bag from the discount store for air travel. I completely wrapped the backpack—one garbage bag from the top and another from the bottom. Then I secured both bags with tape.
This ensured that the backpack was well protected during the flight, and loose straps or buckles were less likely to get caught in the baggage handling system.