Thorns, sharp rocks and everyday wear can damage the material of your waterproof backpack or bag. Even a small hole or tear can let water in.
If you suspect your bag has been damaged, or simply want to be on the safe side before carrying things you really don’t want to get wet, such as a camera, laptop or other sensitive equipment, you can perform a simple waterproof test.
Before you start, make sure the inside of the bag is completely dry so you don’t mistake existing moisture for a leak.
Choose a test that matches how you plan to use the bag. If you mainly need protection from rain, simply wetting the outside is enough. If the bag might fall into the water, you should also test it in a bathtub.
All you need is some water and a few sheets of absorbent paper, such as paper towels or toilet paper.
How to Test Your Waterproof Backpack
1. Check for visible damage
Inspect the material, bottom, corners and welded seams for holes, cuts or worn areas.
2. Put dry paper towels inside and close the bag
Place a few sheets of dry paper inside the empty bag, especially near any areas that look damaged. Make sure the inside is completely dry before you start, and close the bag as you normally would. Don’t forget to put paper inside any waterproof pockets to test those too.
3. Rain test
Want to check if your bag still keeps out the rain? Pour water over the outside or, even better, spray it with a shower. Keep spraying for a few minutes, paying extra attention to any areas you think might be damaged. Avoid using a strong jet of water, as normal rain won’t hit the bag with that much force.
4. Floating test
If your bag might fall into the water, for example when you’re on a boat or walking through rivers, it’s worth testing it in a bathtub, too.
Fill the bathtub with enough water for the closed bag to float freely. Place the bag on the water and leave it there for a few minutes. Then turn it onto the other side and repeat the test.
5. Check the inside
Open the bag and check the paper towels. They should be completely dry. If the paper is wet, take a closer look at the bag to see where the water got in.
What About Submerging the Bag?
If you want to go a step further, you can also test what happens when the bag is fully underwater.
Start by holding the closed bag just below the surface for a few seconds. Take it out and check the paper towels inside. If they’re still dry, try again and leave it underwater a little longer. Check the paper after each attempt.
This lets you see how your bag handles being underwater, even if it isn’t designed for submersion, and gives you a better idea of what to expect if it gets submerged in real life. Just remember that the deeper you go and the longer the bag stays underwater, the greater the water pressure becomes.
What If You Find a Leak?
Small holes and tears can be easily repaired at home with a suitable repair patch. For more extensive damage, such as damaged welded seams or a waterproof zipper, check out our guide to repairing a waterproof bag for advice on possible repair options.
