Why does my waterproof backpack get wet in a rainy day?

Why does my waterproof backpack get wet in a rainy day?

Summary

A waterproof backpack is an essential piece of equipment for any outdoor enthusiast, but how to identify right waterproof bag? There are so many bags in the market called waterproof, and the complaint that why my waterproof backpack got wet in rainy day happened

Why does my waterproof backpack get wet in a rainy day?
Do you ever buy a waterproof bag? Is your waterproof bag really waterproofing to protect your stuffs inside the bag?
A waterproof backpack is an essential piece of equipment for any outdoor enthusiast, but how to identify right waterproof bag? There are so many bags in the market called waterproof, and the complaint that why my waterproof backpack got wet in rainy day happened, although it showed waterproof function. If it happens, I assume that you got a water repellent backpack, not a waterproof one. The confusing function features do exist in the market. Today we’d like to share some relative professional information from our knowledge, hope it will be helpful.

What’s water repellency?
Most of the stitching nylon bags made with water repellent fabric can build up a bag to against the water and rains to protect stuffs from getting wet inside the bag in a short certain time. But it will be wet with strong heavy rains after a long time through the needle holes or zippers. Such kinds of bags with good quality water repellent spray fabric can meet IPX1-4 testing. 
How to build up a real waterproof bag?
However, a real waterproof bag request a good lamination layer onto the fabric to make the fabric strong enough to against water resistance testing by hydrostatic head, quality water resistance materials, good waterproof zipper and advanced seamless voltage technology can create a bag, that’s called waterproof bag.
waterproof backpack
How do we know the waterproof level of our bag?
We arranged our ODM waterproof backpack to SGS lab and tested. Below testing details are sharing with you.
Test Level: IPX7
Test Method: IEC 60529:1989/ AMD2:2013/COR1:2019Test
Test Depth: 1.0meter
Test Duration: 30 minutes
Lab Environment Condition: 15C-35C,25%RH-75%RH
We hope that our sharing is helpful to know what the real meaning of waterproof is.