When this happens, its time to revitalized the water repellency of the bag.
To keep your panniers looking and performing like new, we recommend “Nikwax Tent and Gear Solarproof”. We’ve used it ourselves with great results. Nikwax Tent and Gear Solarproof is a water base spray-on waterproofing and UV blocker that is very easy to apply. Simply wet your pannier and spray the Nikwax Tent and Gear Solarproof evenly on the wet pannier. Wait a few minutes, remove the surplus with a damp cloth and hang to dry.
After you have applied the Nikwax Tent and Gear Solarproof waterproofing treatment, water will bead again and roll off the fabric, preventing it from being absorbed into the fibers of the fabric. Dirt and stains will be easier to remove.