How to Waterproof a Backpack: A Complete Guide to Keeping Your Gear Dry

When you’re out hiking, camping, or commuting in unpredictable weather, a soggy backpack can turn an adventure into a frustration. Wet gear, damaged electronics, and damp clothes are no one’s idea of fun. That’s why learning how to waterproof a backpack is a must for anyone who ventures outdoors—or even just battles a rainy commute. This guide dives deep into practical, proven methods to keep your backpack water-resistant, ensuring your belongings stay dry no matter the conditions. From DIY solutions to gear upgrades, we’ll cover everything you need to know, plus a few bonus tips to maximize protection.

Why Waterproofing Your Backpack Matters

A backpack isn’t just a bag—it’s your lifeline for carrying essentials like food, clothing, gadgets, and emergency supplies. Rain, snow, or an unexpected spill can seep through unprotected fabric, ruining your stuff and weighing you down. Waterproofing doesn’t just shield your gear; it adds peace of mind and extends the life of your backpack. Whether you’ve got a rugged hiking pack or a sleek urban carryall, adding water resistance is a game-changer.

Understanding Your Backpack’s Material

Before you start waterproofing, know what you’re working with. Most backpacks are made from nylon or polyester, both of which are durable but not inherently waterproof. Some high-end models use ripstop fabric or come with a water-repellent coating like DWR (Durable Water Repellent), but even these can wear off over time. Canvas and leather backpacks, while stylish, soak up water unless treated. Check your backpack’s seams, zippers, and fabric—weak points where water loves to sneak in. Knowing your material guides your waterproofing strategy.

Method 1: Use a Waterproof Spray

One of the easiest ways to waterproof a backpack is with a waterproofing spray. These products, often silicone- or polymer-based, create a protective barrier on the fabric that repels water. Here’s how to do it:

1. Clean Your Backpack First: Dirt and grime can block the spray from bonding properly. Use a damp cloth or mild soap to wipe it down, then let it air dry completely.
2. Test a Small Area: Spray a corner to ensure it doesn’t discolor or damage the material.
3. Apply Evenly: In a well-ventilated area, hold the can 6-8 inches away and coat the entire surface, focusing on seams and zippers.
4. Let It Cure: Wait 24 hours for the spray to dry and set.

Popular options include Scotchgard, Nikwax, or Granger’s. These sprays boost water repellency without changing your backpack’s look or feel. Reapply every few months, especially after heavy use or washing.

Method 2: Wax Your Backpack

For a DIY approach with serious water resistance, waxing is a classic trick. Backpack wax (like beeswax or specialized products like Fjällräven’s Greenland Wax) seals the fabric against moisture. It works best on canvas or cotton blends but can also enhance nylon packs. Here’s the process:

1. Prep the Surface: Clean and dry your backpack thoroughly.
2. Rub On the Wax: Use a block of wax and apply it evenly across the fabric, like coloring with a crayon. Focus on high-exposure areas.
3. Heat It In: Use a hairdryer to melt the wax into the material—it’ll soak in and create a waterproof layer.
4. Wipe Off Excess: Remove any leftover residue with a cloth.

Waxing adds a rugged, weatherproof finish, but it can stiffen the fabric and darken colors slightly. Test it on a small patch first.

Method 3: Install a Rain Cover

A rain cover is a quick, no-fuss way to shield your backpack from downpours. These lightweight, packable covers slip over your bag like a shower cap, keeping water out. To use one effectively:

• Choose the Right Size: Covers come in small, medium, and large—match it to your backpack’s capacity (e.g., 20L, 40L).
• Secure It Properly: Look for elastic edges or drawstrings to keep it snug in windy conditions.
• Pack It Smart: Store it in an outer pocket for easy access when rain hits.

Rain covers are affordable and widely available from brands like Osprey or REI. They’re not a permanent fix, but they’re perfect for sudden storms.

Method 4: Add a Dry Bag Liner

For maximum protection, pair your backpack with a dry bag liner. These waterproof sacks sit inside your pack, sealing your gear from moisture even if the outer shell gets soaked. Here’s how to use one:

1. Pick a Size: Match the dry bag to your backpack’s volume (e.g., 30L for a daypack).
2. Load Your Gear: Place clothes, electronics, or anything sensitive inside the dry bag.
3. Seal It Tight: Roll the top down three times and clip it shut—most dry bags are designed to lock out water this way.
4. Pack It In: Slide the sealed dry bag into your backpack.

Dry bags from Sea to Summit or NRS are lightweight and tough, doubling as standalone carriers if needed. This method shines for kayaking, heavy rain, or multi-day trips.

Method 5: Seal Seams and Zippers

Water often sneaks through seams and zippers, even on treated backpacks. To lock them down:

• Seam Sealing: Apply a seam sealer (like Gear Aid Seam Grip) with a brush along every stitch line. Let it dry for 24 hours.
• Zipper Protection: Rub silicone grease or use waterproof zipper tape to block leaks. For extra coverage, opt for a backpack with rubberized or covered zippers next time.

This step takes effort but pays off in torrential conditions.

Bonus Tips for Extra Protection

• Organize with Ziplock Bags: Stash small items like phones or maps in plastic bags for a cheap, fail-safe layer.
• Avoid Overpacking: A stuffed backpack strains seams, making leaks more likely.
• Maintain Your Gear: Reapply sprays or wax as needed—waterproofing fades with wear.
• Test It Out: Spray your backpack with a hose to check for weak spots before hitting the trail.

Choosing a Waterproof Backpack from the Start

If DIY isn’t your thing, consider investing in a pre-waterproofed backpack. Look for features like:

• Waterproof Materials: Polyurethane-coated nylon or TPU (thermoplastic polyurethane) fabrics.
• Roll-Top Closures: Common in dry bags and outdoor packs, these seal out water better than zippers.
• Welded Seams: Heat-sealed stitching beats traditional thread for leak-proofing.

Brands like Patagonia, North Face, and Yeti offer models built for wet environments. They cost more upfront but save you time and hassle.

Common Mistakes to Avoid

• Skipping the Prep: Dirty backpacks resist treatments—always clean first.
• Overdoing Wax: Too much can clog fabric and attract dirt.
• Ignoring Wear: A single waterproofing session won’t last forever; re-treat regularly.

Final Thoughts: Keep Your Adventures Dry

Waterproofing a backpack isn’t rocket science—it’s about picking the right method for your needs and gear. Whether you spray it, wax it, cover it, or line it, the goal is the same: dry stuff, happy travels. Start with what you’ve got, test your setup, and tweak it as you go. Rain doesn’t have to ruin your day—or your backpack.

Next time you’re packing for a trip, ask yourself: Is my gear ready for the weather? With these steps, the answer’s a confident yes. Stay dry out there!