We are often asked whether our bags are completely waterproof. Short answer: The fabric we use is waterproof, but the bags are not seam-sealed. Long answer: There are many reasons for this, as follows:
1) First and foremost, making a completely waterproof bag generally means a bag that uses radio-frequency-welded construction. You can't RF-weld the typical materials we choose to use for our bags; the materials available for RF-welding are generally PVC-tarp-like and not, in our opinion, the most abrasion-resistant. We feel these materials don't hold up well under consistent use. Also, it is worth noting that while there are a few truly waterproof RF-welded bags on the market, many RF-welded bags also have stitches through the tarp, rendering the "waterproof" claim moot.
2) Camping gear gets wet, and then goes into your bags - and if you haven't taken precautions to keep critical items dry, those will then become wet. Examples are numerous and include rain gear once the sun starts shining, a weather- or condensation-soaked bivy or tent, sweaty clothing, etc. In short, you still have to individually waterproof sleeping bags, down jackets, and so on, regardless of whether your bags are waterproof or not. Good old backpacking gear hasn't been waterproof for the last 50 years... and that hasn't stopped anyone from hiking the Pacific Crest or Appalachian Trails.
3) The technology to RF-weld largely belongs to Chinese manufacturers at this point, and the bags we're seeing come out of China are as expected - poorly made. As a company committed to domestic manufacturing, even if we decided that RF-welded PVC-type materials were the way to go (which, thankfully, we haven't), we wouldn't go overseas.
4) Finally, you can certainly seam-seal our bags if you so desire. Remove any stiffeners, flip them inside out, and apply tent seam sealer to all stitches. This is similar to US-made Henry Shires TarpTents, or European-made Hilleberg tents - of highest quality, but not seam-sealed due to prohibitive extra cost and large-scale environmental regulations.
In short, if you're doing a fatbike, coastal, packraft tour, you may need fully waterproof bags. But for typical bikepacking and touring trips in all weather conditions, we genuinely feel the higher-quality materials and construction techniques far outweigh any benefits of waterproof gear.