How to Waterproof Your Backpack: A Step-by-Step Guide

A soggy backpack can ruin a hike, a commute, or a camping trip. Wet gear isn’t just uncomfortable—it can damage electronics, mold clothes, and weigh you down.

But don’t worry: waterproofing your backpack is easier than you think. Whether you’re braving a rainforest or a rainy city, this guide will show you how to keep your stuff dry.

In this article, we’ll cover:

• Why waterproofing matters (spoiler: it’s not just about rain).
  
• 6 proven methods to waterproof any backpack, from budget hacks to pro-level fixes.
  
• How to choose the right gear (with product recommendations).
  
• Common mistakes to avoid.

Let’s dive in.

Why Waterproofing Your Backpack Matters

The water is sneaky. It seeps through zippers, soaks into seams, and pools in corners. Here’s why waterproofing is worth the effort:

• Protect Your Gear: Phones, maps, and sleeping bags hate water.
  
• Stay Comfortable: A dry backpack is lighter and easier to carry.
  
• Save Money: Replacing waterlogged gear adds up.
  
• Extend Backpack Life: Mold and mildew can break down fabrics over time.

Did You Know? Even “water-resistant” backpacks can leak in heavy rain. True waterproofing requires a mix of smart gear and techniques.

Step 1: Know Your Backpack’s Weak Spots

Before waterproofing, identify where water gets in. Most leaks come from:

• Zippers: The #1 culprit. Even “waterproof” zippers can fail under pressure.
  
• Seams: Thread holes let water seep through the stitching.
  
• Fabric: Non-coated materials like canvas absorb water.
  
• Lid/Top: Rain can drip into open or loosely closed tops.

Tip: Test your backpack’s limits with a garden hose or shower. Watch where water pools or leaks.

Step 2: Choose Your Waterproofing Method

There’s no one-size-fits-all solution. Your choice depends on your budget, backpack material, and adventure type. Here’s a quick comparison:

Method 1: Use a Rain Cover

A rain cover is a stretchy, waterproof sleeve that fits over your backpack. It’s the easiest way to block rain, snow, or mud.

How to Use It:

• Buy a cover sized for your backpack (e.g., 20L, 40L).
  
• Stretch it over the backpack, ensuring full coverage.
  
• Secure with elastic edges or buckle straps.

Top Picks:

Osprey Ultralight Raincover: Durable, packs into a tiny pouch.
Sea to Summit Ultra-Sil: Lightweight and affordable.

Tip: Choose a bright color (like neon yellow) for visibility in storms.

Method 2: Apply Waterproofing Spray

Waterproof sprays add a protective layer to fabrics. They work best on nylon, polyester, or treated canvas.

How to Do It Right:

• Clean the backpack with mild soap and water. Let it dry.
  
• Spray evenly over the entire surface (outside only).
  
• Focus on seams and zippers.
  
• Let it dry for 24 hours.

Best Products:

Nikwax TX.Direct: Eco-friendly, lasts 2–3 months (varies with exposure).
Scotchgard Water Shield: Quick-drying, budget-friendly.

Warning: Avoid sprays on leather or suede—they can stain or crack.

Method 3: Seal the Seams

Seam sealing is a game-changer. Most backpacks have stitched seams that let water in. A seam sealer fills those gaps.

Step-by-Step Guide:

• Buy a seam sealer (e.g., Gear Aid Seam Grip).
  
• Turn the backpack inside out.
  
• Apply a thin line of sealer along all seams.
  
• Let it dry for 12–24 hours.

Tip: Use a toothpick to spread the sealer into tight spaces.

Method 4: Use Dry Bags or Liners

Dry bags are waterproof sacks that go inside your backpack. They’re 100% reliable—even if your pack gets submerged.

How to Pack Like a Pro:

• Roll the top of the dry bag 3–4 times to seal.
  
• Organize gear by category:

Small dry bags: Phone, wallet, first-aid kit.
Large liners: Clothes, sleeping bags.

Top Brands:

Sea to Summit Big River Dry Bag: Tough and affordable.
Earth Pak Waterproof Backpack: Built-in dry compartments.

Case Study: Kayakers on the Colorado River swear by dry bags for multi-day trips. (Source: Outside Magazine)

Method 5: Wax Coating (DIY Waterproofing)

Waxing works wonders on canvas or cotton backpacks. It’s a classic method used for decades.

What You’ll Need:

Beeswax or Otter Wax bar.
Hairdryer.
Clean cloth.

Steps:

• Rub the wax onto dry fabric in circular motions.
  
• Use a hairdryer to melt the wax into the fibers.
  
• Buff with a cloth to remove excess.

Note: Wax adds weight and stiffness. Reapply every 6 months (depending on usage frequency).

Method 6: Emergency Plastic Lining

No gear? Use a trash bag or shower cap as a quick fix.

How to Do It:

• Line the inside of your backpack with a heavy-duty trash bag.
  
• Pack gear inside the bag.
  
• Fold the top over to seal.

Tip: Use bright orange bags for visibility in emergencies.

Step 3: Maintain Your Waterproofing

Waterproofing isn’t a one-time job. Follow these tips to keep it effective:

• Reapply spray/sealer every 3–6 months.
  
• Wash gently: Harsh detergents strip waterproof coatings.
  
• Air dry only: Heat from dryers can damage fabrics.

Check your backpack after each trip for wear and tear.

Common Mistakes to Avoid

• Ignoring Zippers: Use zipper lubricant (like McNett Zip Care) to keep them smooth and watertight.
  
• Overloading: Stuffed packs strain seams, causing leaks.
  
• Skipping the Test Run: Always test your waterproofing at home first.

FAQs

Q: Can I make a non-waterproof backpack fully waterproof?
A: Not entirely, but combining a rain cover + dry bags gets close.

Q: Is waterproof spray safe for all fabrics?
A: Check the label. Avoid sprays on leather, suede, or down-filled gear.

Q: How do I dry a wet backpack?
A: Hang it upside down in a ventilated area. Never store it wet!

Final Thoughts

Waterproofing your backpack is like buying insurance for your gear. With the right methods—whether a $10 spray or a bombproof dry bag—you’ll stay dry in any storm.

Check out our selected backpacks of 2025 or Learn How to pack a tactical backpack.