How to Test if Your Backpack Is Still Waterproof?

You bought a “waterproof” backpack for your adventures, but is it really as watertight as it claims?

Over time, fabrics wear down, coatings fade, and that once-impervious pack might start leaking when you least expect it. Instead of finding out the hard way (with soaked gear on the trail), it’s smart to test if your backpack is still waterproof.

In this handy guide, we’ll show you how to check your bag’s water resistance at home. From a simple spray check to a full-on shower simulation, you’ll learn step-by-step methods to ensure your pack can handle rain and rugged conditions.

We’ll also cover what telltale signs of leaks to watch for, how to interpret the results (which leaks are fixable and which mean retirement for your pack), and when to re-test. Let’s make sure your trusty backpack is truly ready for the elements!

Why You Should Test Your Backpack’s Waterproofing

Just because a backpack is sold as “waterproof” or “water-resistant” doesn’t guarantee it will keep your gear dry in every situation. Manufacturers face challenges making packs completely watertight due to multiple seams, zippers and compartments.

Many packs use waterproof fabrics and coated zippers, yet still aren’t submersible. In heavy rain, water can sneak in through tiny stitching holes or worn-out coatings. In fact, experienced users note that most “weather-resistant” packs (aside from fully sealed roll-top dry bags) will eventually let rain in during prolonged showers.

Bottom line: If you plan to hike, camp, or commute in the rain, it pays to check your backpack’s waterproofness. A quick at-home waterproof backpack test can save your laptop, clothes, and snacks from a soaking. Plus, testing is easy and kind of fun – think of it as a science experiment for your gear!

3 Testing Methods to Check Your Pack’s Waterproofness

When it comes to leak testing your backpack, there are a couple of approaches. We recommend starting with a gentle spray test and then moving to a more rigorous shower or hose test for full assurance. You’ll also want to do a quick visual check of the bag’s key areas. Here are the methods, from basic to advanced:

1. Quick Visual Inspection (Optional but Helpful)

Before dousing your pack with water, give it a once-over:

1. Inspect the seams and zippers: Look closely at all seams inside and out. Are any threads loose or holes visible where stitching goes through? Check if seam tape (if your pack has it) is peeling off. Also inspect zippers – especially “water-resistant” zippers – for any gaps or damage. These spots are common leak points.
2. Check the fabric coating: Many backpacks have an inner waterproof coating (often polyurethane) or a Durable Water Repellent (DWR) finish on the outside. Over years, these can wear out or degrade. If the inside of your pack feels flaky, cracked, or sticky, the waterproof coating might be compromised. (A sticky interior often indicates the coating is breaking down – a known aging issue for packs.) Make note of any areas that look worn.
3. Look for small tears or holes: Even a tiny puncture can let water in. Inspect the bottom of the pack and corners for abrasion holes. If you find any, you’ll know those need patching or extra attention during testing.

This inspection can give you clues about where a leak might occur. It also prepares you to fix obvious issues before the water test (for example, you might decide to patch a hole or avoid submerging a part with a broken zipper). Once you’re done with the check-up, it’s time to get the water flowing!

2. The Basic Water Spray Test (Quick Check)

This is a simple test to see if water immediately penetrates your pack or if it beads off. It’s not as conclusive as the full shower test, but it’s a good quick check of water resistance:

• How to do it: Take a spray bottle filled with water (or a gentle hose nozzle) and mist the exterior of your backpack thoroughly. You can also use a light sprinkle from a watering can or stand outside in a mild drizzle for a few minutes.

• What to watch: Does the water bead up on the fabric surface and roll off, or does it soak in and darken the material right away? If you see water beading, that’s a good sign the DWR on the fabric is still working. If the fabric immediately darkens with wet patches, it means it’s absorbing water – a sign that the water-repellent coating is gone or the material is permeable.

• After spraying: Open the pack and check inside for any dampness. For this quick test, you might not have lined it with anything, so just feel with your hand or use a tissue to swipe the interior. If it’s totally dry, great. If you already feel moisture inside from a light spray, the pack is definitely no longer waterproof and you’ll need to take measures (and certainly do the next test).

This basic test is like a “first line of defense.” If your bag fails here (soaks through from just a light spray), you have your answer – it’s not waterproof. Often the culprit is a worn-out DWR finish. You can usually re-proof that by applying a waterproofing spray, but we’ll get to fixes later. If it passes the spray test (outer fabric repels water and no immediate soak-through), move on to the more rigorous hose/shower test for a thorough check.

3. The Garden Hose/Shower Test (Simulate a Downpour)

Consider this the ultimate backpack rain simulation – you’ll mimic a heavy rainstorm and see if any water leaks in. This is the main testing method and our favorite DIY “rain lab” experiment. It’s essentially a controlled leak test for your backpack. Grab your garden hose or showerhead and let’s get testing!

What you’ll need: Your backpack, dry paper towels or newspaper, a garden hose with spray nozzle (or an indoor shower/bathtub), and a few minutes of your time. It helps to have a helper, but not required.

Step-by-Step: The Full Waterproof Backpack Test

1. Empty the backpack and prep it

Take everything out of your bag – you’ll want it empty for the test (you don’t need your gear getting wet if it leaks!). If the pack is dirty, you might give it a quick wipe-down first; clean fabric will let water roll off more realistically and you won’t be dealing with mud. Now line the interior with dry paper towels or newspaper.

Place them into all compartments, pockets, and corners of the pack. These will act as moisture detectors – any water ingress will show up as wet spots on the paper. Zip up or buckle the pack closed as you normally would in rain. I

f your bag has a roll-top closure, roll and clip it shut. For flap-style lids, buckle them as usual. Basically, seal it the way you’d carry it in a storm.

Pro tip: If using a shower, you might stuff the pack with a pillow or crumpled clothes behind the paper towels to mimic its shape and give it some rigidity. This can also stop water from just pooling in an empty flop of fabric.

2. Choose your “rain”: shower or hose

You can use an indoor shower/tub or go outside with a garden hose. Either way, aim for a realistic rain effect. If using a hose, put it on a shower-like spray setting (not a single jet stream).

A nozzle that can disperse water over a broad area works best to simulate rainfall. If using a shower, a standard showerhead is fine – you might hold the pack at various angles under it.

Pro-tip: In a bathtub, avoid letting the pack sit in backed-up water. You might hang it or hold it so water hits it but it’s not resting in a puddle (unless your goal is to also test the very bottom against standing water).

3. Soak it like a rainstorm

Time to play rain god! Spray the backpack from all sides, especially the top (since rain falls downward). Ensure water hits the front, sides, zippers, and seams. If outside with a hose, you can hang the pack on a line or tree branch, or set it on a stool, and move around it with the hose.

Keep the spray going for several minutes. There’s no exact science, but around 5 to 10 minutes of heavy spraying is a solid test for a rainstorm.

Make sure to get water into all those nooks – along the zipper lines, the seams, the bottom, etc. You want to expose any weak points. Feel free to gently squeeze or flex the pack while wet (for example, press on the front as water hits, to mimic the pressure of wind-driven rain).

Note: If your pack is truly waterproof (like a dry bag type), you could even briefly shower it from below to test the bottom seams – but for most backpacks, focus on simulated rain from above and the sides, not full submersion.

4. Observe during the test

While you’re spraying, watch what’s happening. Is water beading up and rolling off on most of the fabric? (Good sign.) Do you see any immediate penetration at certain spots? For example, you might notice dark wet patches forming on areas of the fabric – those are places where the outer layer is saturating.

Pay extra attention to zippers and seams: do you see water seeping through zipper coils or along seam lines? If so, note that mentally – you may have found a leak path. Some packs with flaps over zippers will do fine until water comes at a certain angle. This is all useful info.

5. Stop and open it up

After a thorough drenching, turn off the water and carefully open your backpack. (It’s best to do this in a dry area so new water doesn’t drip inside as you open it. Towel off the outside quickly if needed.)

Now, inspect all the paper towels/newspaper you lined the pack with. This is the moment of truth! Are they still completely dry, or do you see damp spots? Check each piece, especially in corners, near seams, and under zippers. Even a small wet patch indicates water got in.

Sometimes you might find a few drops in the bottom, or soaked areas corresponding to where you suspected (e.g. the front zipper seam). If everything is bone dry, congrats – your pack passed with flying colors. If not, don’t panic – we’ll interpret the results in the next section.

6. Test specific leak points again (optional)

If you did find water inside, you can do a little detective work. Close the pack again and re-spray just the area where the leak was detected. For instance, if you found wet paper at the bottom of the main compartment, aim water at the bottom and lower seams specifically to see exactly how it’s entering.

This can confirm, say, “ah, it’s seeping through the corner seam” vs. “it came through the fabric itself.” This targeted testing helps in planning a fix.

This garden hose/shower test is essentially the same kind of trial product reviewers use. (In fact, Travel + Leisure testers check “waterproof” packs by blasting them with showerheads and seeing if tissue paper inside stays dry. By the end of this, you’ll know for sure whether your backpack is truly watertight under a downpour or if it has hidden vulnerabilities.

What Signs to Look For: Did Water Get In?

After testing, assess the evidence. Here are the key signs that indicate your backpack isn’t fully waterproof, and what they mean:

• Wet Patches Inside: This is the most obvious fail sign. If the paper towels or items you placed inside came out wet or even damp, water penetrated the pack. Note where you found the wet patches. For example, wetness only in one corner might mean a seam leak there, while general dampness could mean the fabric is soaking through. Any interior wet patch means your gear would have gotten wet in real conditions, so your pack’s waterproofing has been compromised at that spot.

• Dark, Damp Spots on the Outer Fabric: Did parts of the exterior fabric turn dark with moisture during the test? This “wet out” effect (where water saturates the fabric instead of beading) is a sign that the DWR (Durable Water Repellent) on the surface is gone. While a soaked shell isn’t an immediate leak by itself (the waterproof layer might still stop water), it leads to problems. Once fabric is saturated, water can more easily seep through seams or pressure points. In short, if your pack’s outer is sopping and heavy, it’s no longer shrugging off rain. (Outdoor experts say that when your waterproof gear shows dark soak patches, it’s time to re-proof it).

• Leaking Seams: Check along all seams inside the pack. Do you see water droplets or damp lines exactly where fabric panels are stitched together? If yes, those seams are leaking. Seams are usually the weakest link because needle holes can let water in. Some high-end packs have taped or sealed seams; if those tapes peel or the seam sealer wears off, leaks happen. Leaky seams often cause localized wet spots in your test (for instance, a ring of wetness around the base seam). This is something you can often fix (with seam sealant) which we’ll discuss soon.

• Zipper Leakage: Water-resistant zippers (like YKK AquaGuard zips) are common on packs, but they aren’t foolproof. If your test reveals water inside pockets or the main compartment right behind a zipper, the zipper could be the entry point. Perhaps water dripped through the gaps in the zipper teeth or between zipper ends. Also, check if the content just inside the zipper (like the top of the main compartment) is wet. Zippers usually resist light rain but can leak under heavy, direct water pressure. No surprise – they’re essentially a row of tiny interlocking teeth, not a solid seal.

• Wicking through Fabric or Straps: Sometimes water can wick through areas like shoulder straps, back padding, or webbing, especially if those got drenched. For instance, a non-waterproof foam backpanel can soak water and slowly transfer it inside. If your test shows the interior wet near where straps attach, it might be capillary action drawing water inward. This is a tougher one to completely prevent without special design, but good to note.

On the flip side, if none of these signs appear – the inside is dry and the outside mostly beaded water – then your backpack is still in great waterproof shape! You can be pretty confident it will handle real rain. Just remember a truly brutal storm or hours of exposure might eventually push any “water-resistant” bag to its limits. But for general use, a passed test is reassuring.

Next, let’s interpret any failures and see which ones you can address with a bit of DIY waterproofing, and which ones might mean it’s time for extra protection or a new pack.

Interpreting the Results: Fixable or Fail?

So your backpack test revealed some leaks, what now? Not all waterproofing failures are equal. Some can be easily fixed or mitigated, while others indicate the pack’s best days are behind it (or that it was never fully waterproof to begin with). Here’s how to interpret your test results and plan next steps:

• Minor Seepage at Seams: Fixable. Leaky seam? You can usually solve this with some seam sealer. Products like Gear Aid Seam Grip are made for exactly this purpose – painting a thin layer of sealant over the seam holes to plug them. In fact, gear experts recommend seam sealing if you notice leaks; it’s a common fix for tents and can work on packs too. To fix, ensure the seam is dry, turn the pack inside out if possible, and apply a seam sealer along the stitching line (many come with a brush applicator). Let it cure fully (often 24 hours) before next use. This can dramatically improve waterproofness by closing those needle holes.

• Wetted-Out Fabric (DWR Failure): Mostly fixable. If your pack’s fabric is soaking water (no beading), it likely needs a new DWR treatment. Over time, the factory DWR wears off (from abrasion, dirt, etc.), causing the shell to absorb water. You can restore water-repellency by applying a waterproofing spray or wash-in product designed for technical fabrics. This won’t make a non-waterproof bag into a dry bag, but it will help the fabric resist rain and not get heavy and saturated. Keep in mind, DWR renewal is maintenance you might have to repeat every so often, as needed – typically every year or two depending on use.

• Zipper Leaks: Workaround available. Unfortunately, you can’t really “fix” a zipper to be more waterproof (aside from replacing it with a better one, which is complex and costly). If your test shows zippers are a problem, there are a few strategies:

  • Ensure during rain use that zipper pulls are fully closed and, if the zipper has a covered flap, that the flap is properly positioned.

  • You can try rubbing a bit of zipper wax or candle wax on the zipper; some people do this to help repel water (it’s a trick often used on older tent zippers). It’s not a perfect seal but can help droplets roll off.

  • The best solution: protect those zip areas with an extra layer. For instance, use a rain cover over the backpack (so zippers aren’t directly exposed) or put critical items in internal dry bags. If it’s a laptop pocket zipper leaking, keep the laptop in a sleeve or dry sack inside as a fail-safe. Essentially, acknowledge the zipper’s limitation and add redundancy (like a pack cover or liner, which we’ll discuss below).

• Small Holes or Tears: Fixable. If water came through a tiny hole (say you found a wet patch exactly where there’s a puncture in the fabric), you can patch it. Use a gear repair patch or tape (Tenacious Tape is excellent for this) on both sides of the hole if possible. Seam Grip glue can also seal small punctures. Patching will restore that area’s waterproofness and prevent the hole from growing. Just make sure to use a waterproof patch material. Many outdoor gear patches are designed to be waterproof and can solve this easily.

• Wicking Straps/Panels: Mitigatable. As mentioned, if the design of the pack has absorbent parts (like foam) that get soaked, you can’t fully waterproof those without major modification. The best you can do is ensure any sensitive gear inside is further protected. Consider using a pack liner (a large waterproof bag inside your backpack) or individual dry bags for important items. That way, even if some water does work through via a soaked strap, your gear stays dry. Many hikers do this by default with even the best packs, because it guarantees dryness.

• Large Area Fabric Leaks: If you discovered that the fabric itself is no longer waterproof over a big area (e.g., the coating has deteriorated so much that rain seeps straight through the material, not just seams), this is tougher. Reapplying a DWR helps only with surface water repellency, but if the internal waterproof coating is cracked or gone, water can permeate. There are urethane coating products (similar to tent waterproofing kits) that you can paint on the inside of a pack to renew its waterproof layer, but it’s a bit messy and not always lasting. If the pack is old and the PU coating is peeling off or sticky, you might be fighting a losing battle. In such cases, using a pack liner or dry bags inside is the most reliable solution, or consider retiring the pack for a new one if waterproofness is critical. Sometimes, it’s just the end of life for that feature (the pack might still be structurally fine for dry weather use).

If your backpack came out totally dry, fantastic! That means its waterproof features are working well. To keep it that way, consider periodic maintenance: clean the pack occasionally (dirt can cause waterproof fabrics to "wet out"), and renew the DWR once it starts to show those dark soak spots in rain. Also, even though it passed a 5-10 minute test, if you’re heading into an all-day deluge, you might still use a pack rain cover or liner as extra insurance – it never hurts to double down if you expect extreme conditions. Think of it like belt-and-suspenders for important trips.

Most small leaks (seams, tiny holes) are fixable with affordable gear care products. DWR can be reapplied to help fabric bead water again. Big inherent weaknesses (like unsealed zippers or major coating failure) are usually manageable with workarounds like covers or liners, if not outright fixable. Very few issues mean you must scrap the pack; however, if you find multiple leak points and don’t want the hassle of patching/sealing, you might conclude that the pack is only good for fair-weather use and invest in a more waterproof model for heavy rain adventures.

Before we wrap up, one more thing: testing and waterproofing aren’t one-and-done. Let’s talk about when you should re-test your pack and keep an eye on its waterproof status.

When and How Often to Retest Your Backpack

Waterproof performance isn’t permanent. Your backpack’s protection can change with time and use, so it’s smart to retest or check your pack periodically. Here are some guidelines on when to conduct a waterproofness check again:

• After a long period of disuse: If your pack sat in the closet for a year or two, especially in a hot attic or damp basement, its waterproof coating could have deteriorated. Give it a test before the next trip – materials can break down even when not actively used (for example, polyurethane coatings can hydrolyze and become less effective over years).

• Before a big trip or rainy season: Heading on a multi-day hike where you know you’ll hit rain? Or as autumn monsoons approach? Do a quick hose or shower test a week or so beforehand. It’s better to discover any issues at home than out in the wilderness. This also gives you time to reapply DWR or seam sealer if needed.

• After heavy use or abrasion: If you’ve been rough with your pack – bushwhacking through branches, scrambling over rocks, frequent travel – the wear and tear can compromise waterproofing. Abrasion might thin out fabric or tear seam tape. It’s a good idea to test again after such heavy use, or at least inspect for damage. For instance, if you notice the pack’s outer layer now wets out in rain where it used to bead, that’s a cue to re-proof it and test.

• After applying any waterproofing fixes: Whenever you do a fix (seam sealing, DWR spritz, patch a hole), you should verify the fix. Once the seam sealer is dry or the spray treatment is set, do another controlled water test on that area. This confirms that the repair worked and the leak is indeed resolved.

• Regular annual check-up: For peace of mind, you might make it a routine to test your gear annually. Many outdoor folks do a gear check at the start of a hiking season. Since tents and rain jackets often need re-proofing every 1–3 years, the same interval is a good rule of thumb for backpacks. An annual mini-test (even just the spray bottle method) can tell you if it’s time to refresh the waterproofing.

Remember, every pack and usage pattern is different. If you live in a dry area and rarely see rain, you might not need to test as often. Conversely, if you’re constantly in downpours, you’ll be much more vigilant. Let experience be your guide – if you ever get a slightly damp item from inside your pack after an outing, treat that as a sign to do a thorough test and maintenance.

Next Steps: Waterproofing Solutions if Your Pack Fails

If your backpack didn’t pass the waterproof test, don’t worry! Failing the test isn’t the end – it’s an opportunity to improve your pack’s waterproofing. There are several effective ways to restore or enhance your bag’s water resistance:

• Re-waterproof your backpack: Whether it’s seam sealing, applying waterproof spray, or patching holes, these DIY fixes can restore much of your pack’s lost waterproofing. For a detailed guide on how to do this, check out our full guide on waterproofing your backpack. We cover everything, from reapplying DWR to seam sealing, to bring your bag back to rain-ready condition.

• Use a pack liner or dry bags: As a quick solution, use a waterproof liner inside your backpack. This extra layer will protect your gear even if the bag’s outer fabric isn’t fully waterproof. You can also pack critical items in individual dry bags for extra protection. It’s an easy and reliable backup for any backpack.

• Get a rain cover: A rain cover is like a waterproof shower cap for your pack. If your backpack leaks, a rain cover will protect it during downpours, though it’s not foolproof in heavy wind or stormy conditions. It’s a lightweight, packable solution that can be a lifesaver if you need to double-check the waterproofing.

• Consider an upgrade for extreme conditions: If you’re regularly in wet environments, a fully waterproof dry bag-style backpack could be the right choice. With welded seams and roll-top closures, these backpacks are designed to withstand extreme conditions. While they may be overkill for most hikers, they’re ideal for activities like packrafting or carrying sensitive gear in heavy rain.

After implementing these fixes, be sure to retest your pack to confirm its waterproofness. Testing again will show you the improvements – after applying seam sealer or refreshing the DWR coating, you may notice that those previously damp paper towels are now completely dry!

Conclusion

Testing if your backpack is still waterproof is a simple yet essential task for any outdoor enthusiast. It lets you discover issues in a controlled way and take action before your next adventure.

With a fun at-home rain simulation, a few towels, and maybe a garden hose, you can ensure your pack is ready for the worst weather. If it passes – excellent, you’ve got peace of mind. If not – now you know exactly how to get it back up to snuff, whether by DIY fixes or adding extra protection.

So go ahead and give your backpack a waterproof check-up. Your future self, trudging through a rainstorm with dry gear, will thank you for it.

Happy testing, and may all your trails be a little less soggy!

FAQ

Can I waterproof a backpack if it has a leather exterior?

Yes! Leather requires a different approach to waterproofing. Instead of using typical fabric DWR sprays, you'll want to use a leather-specific waterproofing balm or wax. These products will condition the leather while adding a water-resistant barrier. Be sure to apply it in thin, even layers, and reapply it as needed, especially if you notice the leather starting to absorb moisture. Avoid using standard fabric sprays as they might damage the leather's texture.

How often should I reapply a waterproofing spray?

The frequency depends on the level of use and environmental exposure. As a general rule, reapply a Durable Water Repellent (DWR) spray every 6-12 months or after heavy use or washing. If you notice that water no longer beads up on your pack's surface or if the fabric begins to absorb water again, it’s time to reapply. Hikers and adventurers in particularly wet conditions may need to reapply more often.

My backpack has a waterproof liner. Does that mean I don’t need to worry about the outer fabric?

Not exactly. A waterproof liner is great for keeping your gear dry from internal leaks, but it doesn’t mean the pack’s exterior is impervious to rain. The outer fabric can still absorb water, which adds weight and makes the pack uncomfortable to carry. It’s important to also maintain the outer fabric’s water resistance with sprays or coatings to ensure your gear stays dry and your pack remains lightweight.

Will a rain cover protect my backpack during heavy downpours?

A rain cover provides a great layer of protection against light to moderate rain, but it’s not foolproof during heavy downpours or extreme conditions. Water can sometimes get between the pack and cover, especially if the rain cover isn’t fitted perfectly or if strong winds blow the rain sideways. If you’re going into heavy rain or a storm, consider pairing the rain cover with a waterproof liner or dry bags for extra protection.

Can I test my backpack for waterproofness if it's made of a delicate or vintage fabric?

Testing a delicate or vintage fabric can be trickier, especially if you’re concerned about damaging it. Lightly spraying water (with a spray bottle, not a hose) is a gentler test, and it can help you assess how the material reacts without soaking it. Be sure to test in an inconspicuous area first, and if you notice any fabric damage or discoloration, it’s best to avoid further testing. For vintage fabrics, consider applying a mild water-repellent spray to maintain the look and integrity of the material without harsh tests.