How to Care for Dry Sacks So They Stay Waterproof

Quick answer

Rinse your dry sack with fresh water after every trip, wash it by hand with mild soap only when it is dirty, and air-dry it fully before storing it loose and unrolled. Avoid heat, solvents, and long-term compression, because those are what break down the coating and seams that keep a dry bag waterproof.

A dry sack is only waterproof until something wears down its coating, clogs its closure, or stresses its seams. Most failures are not sudden; they build up from grit, sunscreen, and the way you pack and store the bag between trips.

The routine below is the same one we recommend for the dry sacks we sell, and it works whether you are cleaning a small ditty bag or a large sleeping bag sack. It takes a few minutes after each trip and can add seasons to a bag's life.

Why dry sacks stop being waterproof

Dry sacks rely on a waterproof coating or film bonded to the fabric, plus welded or taped seams. That coating is tough, but it does not like abrasion, heat, or harsh chemicals. Sand and grit inside a pack act like sandpaper, and sunscreen, insect repellent, and fuel residue can soften or degrade the coating over time.

The roll-top closure is another weak point. If the edges are creased, dirty, or folded unevenly, water can wick through the folds. Most leaks people blame on the fabric actually start at the closure or a seam that has been stressed by over-compression.

• Grit and sand abrade the coating from the inside
• Sunscreen and DEET can degrade waterproof films
• Sharp creases in the roll-top create wicking paths

Washing a dry sack without damaging it

Fill a sink or tub with lukewarm water and a few drops of mild soap, then hand-wash the sack with a soft sponge or cloth. Pay attention to the roll-top edges and the inside corners where grit collects. Do not use a washing machine, a dishwasher, or a brush with stiff bristles, because all three can scratch the coating.

Rinse thoroughly with fresh water until no soap remains. Soap residue is slippery and can attract dirt, and it can also interfere with the coating's water repellency. If the sack held food or fuel, wash it separately so odors and residue do not transfer to your sleeping bag.

• Use lukewarm water, never hot
• Skip bleach, solvents, and heavy-duty cleaners
• Rinse until the water runs clear and not slippery

Drying and checking the closure

Turn the sack inside out and hang it in the shade with the roll-top open. Air movement matters more than heat, so a breezy spot is better than a sunny one. Direct sun and hot cars can make the coating brittle, so keep drying temperatures moderate.

While it dries, inspect the roll-top edges and seams for grit, small cuts, or stiff spots. Wipe the closure clean with a damp cloth and let it dry completely before you roll it. A closure that is clean and flat seals far better than one with a sandy crease.

• Dry inside out in the shade, not in direct sun
• Check for grit or cuts along the roll-top
• Never store a damp sack, even overnight

Storing dry sacks so they last

Store dry sacks loosely rolled or folded, not compressed into a tight ball. Long-term compression creates permanent creases that can crack the coating, especially in cold weather. Keep them away from heaters, fuel cans, and anything with sharp edges.

If you use a dry sack as a sleeping bag stuff sack, give it a little slack rather than cranking it down as far as it will go. The Dry Sack + Compression Caps is built with separate compression caps that never stress seams, which is a useful design detail if you tend to over-compress your bag. For small items, a Ditty Dry Sack keeps essentials organized so you are not digging through the main bag and stressing the closure every time.

• Store loose, not compressed
• Keep away from heat and solvents
• Use a dedicated small sack for tiny essentials

Your dry sack care routine, step by step

1. Empty and shake out grit: Turn the sack inside out and shake out sand, crumbs, and debris. Wipe the roll-top edges with a dry cloth. Checkpoint: if you feel grit along the closure, keep cleaning before you wash.
2. Hand-wash with mild soap: Use lukewarm water and a few drops of mild soap. Sponge the inside and outside, focusing on the roll-top and corners. Mistake to avoid: never use a washing machine, bleach, or solvents.
3. Rinse until the water runs clear: Rinse with fresh water until no soap remains and the surface no longer feels slippery. Checkpoint: soap residue attracts dirt and can reduce water repellency.
4. Air-dry inside out in the shade: Hang the sack open in a breezy, shaded spot. Turn it occasionally so trapped moisture escapes. Mistake to avoid: direct sun and hot cars can make the coating brittle.
5. Inspect seams and closure: Look for cuts, stiff spots, or grit along welded seams and the roll-top. Wipe the closure clean and let it dry fully. Checkpoint: a clean, flat closure seals far better than a sandy one.
6. Store loose and unrolled: Fold or loosely roll the sack and keep it away from heat, fuel, and sharp objects. Do not compress it into a tight ball. Next step: give stuff sacks a little slack when packing your sleeping bag.

Dry sacks built for the long haul

• Dry Sack + Compression Caps: Lightweight, fully welded, water-tight storage for your sleeping bag with separate compression caps that never stress seams. Fully welded seams and separate caps reduce the two most common failure points, so the sack holds up to repeated compression and stays waterproof longer.
• Ditty Dry Sack: A small, smart storage bag with a wide roll-top opening and a transparent panel that lets sunlight illuminate your gear. The wide opening makes it easy to clean and dry inside, and the transparent panel helps you find small items without emptying the whole sack.

A few minutes of rinsing, drying, and loose storage after each trip is all it takes to keep a dry sack waterproof for years. Treat the coating and closure well, and your gear stays dry when it matters most.