DWR (durable water repellent) wears off gradually, and reproofing restores it rather than fixing a defect — it's routine maintenance, not a sign of a damaged pack.

When reproofing is needed

A simple bead test tells you: splash a small amount of water on the fabric. If it beads and rolls off, the DWR is still working. If it darkens and soaks in instead of beading, it's time to reproof. Abrasion against rock and brush, UV exposure, and built-up trail dirt all wear DWR down faster than time alone, so a heavily used pack needs reproofing more often than one that mostly stays in a closet.

Pack under a garden hose spray to test beading

The reproofing steps

  • Clean the pack with a gentle, non-detergent soap — the same approach used for washing a hiking backpack generally — since dirt and body oils block a new coating from bonding to the fabric.

  • Check the product label on whether the fabric should be wet or dry when you apply it: Nikwax's pack and tent spray goes on clean, wet fabric, while other treatments call for dry fabric.

  • Apply a spray-on DWR treatment made for packs evenly across the face fabric, following that specific product's label for coverage and dry time.

  • Let the pack air dry fully, away from heat and direct sun. Nikwax says its pack spray should be air dried only, and Gregory and ULA say never to use a dryer.

    • Woman spraying a treatment onto a clean damp pack outside

    How often

    A pack used weekly through hiking season typically needs reproofing once or twice a year; occasional use stretches that interval further, sometimes to once every year or two. Reproofing the fabric alone doesn't address leaky seams or zippers, so it works best alongside a rain cover and pack liner rather than as a standalone fix for staying dry in the rain.

    Crisp round water drops beading on freshly treated pack fabric outdoors