Are Waterproof Backpacks Really Waterproof? How to Tell

A backpack labelled waterproof can still let water in. Most do it through the same few places: stitched seams, a closure that folds over only once, and zips that leak at the ends. Knowing where those weak points sit tells you more about a bag than any label on the front.

This guide explains what actually keeps water out, what the IPX ratings mean, and how to tell a waterproof backpack from a water-resistant one before you trust it with your phone, passport or a dry change of clothes.

Waterproof and Water-Resistant Are Not the Same

A water-resistant backpack slows water down. Coated fabric sheds rain for a while, but stitched seams, open zips and a loose top let water through once the bag is soaked or splashed hard.

A waterproof backpack seals the main routes water takes. That takes three things working together: a material water can't pass through, seams with no needle holes, and a closure that seals instead of simply covering the opening. Any external zip or opening needs its own protection and its own rating.

• Material - PVC tarpaulin is a woven polyester base fabric (the scrim) coated in PVC. The weave provides tear strength, and the coating blocks water completely. POD uses 0.5mm 500D PVC tarpaulin on both backpacks.
• Seams - stitching punches holes along every seam. Electronic heat welding fuses the panels together instead, so water has nothing to follow.
• Closure - a roll-top seals when you roll it forward three times and clip it down. The roll is the seal. The buckles only hold it in place.

The Zip Is Where Most Bags Leak

A waterproof zip has coated tapes that press together when it closes, which keeps water out along the teeth. The weak point is at the ends.

Most zips are cut to length from a continuous roll. Cutting leaves open ends where water can work its way in, and it can loosen the stitching that holds the teeth to the tape. A zip made to its exact length with moulded ends has no cut edge, because the moulding seals both tips.

POD pays more for the made-to-length version on every pocket zip on the 25L and 40L. It closes the gap a roll-cut zip leaves open, and you only notice it when it's missing.

What the IPX Ratings Actually Mean

IPX ratings come from an international standard for how well a product resists water. Each rating describes a specific test, not a single ladder. A product rated for immersion has not automatically passed the jet test, which is why some products carry two ratings.

• IPX6 - protects against powerful water jets from any direction. Think heavy rain, waves breaking over the bag, or a hose. It is not a submersion rating.
• IPX7 - protects against immersion in water up to 1 metre deep for 30 minutes.
• IPX8 - protects against continuous immersion beyond 1 metre, under conditions the manufacturer specifies.

Ratings often apply to one part of a bag, not the whole thing, so check what each rating covers. On POD bags, the front pocket zips on the 25L and 40L are IPX7. The 2L Waterproof Cross Body Bag is IPX8. The backpacks' main compartments are 100% waterproof and airtight once rolled and sealed, so a sealed bag traps air and its contents stay dry through brief accidental submersion.

How to Tell If a Backpack Is Really Waterproof

Check these before you rely on a bag around water.

• Look at the seams - welded seams look smooth and fused. Stitched seams show a line of thread, even under tape.
• Check the closure - a roll-top that rolls at least three times seals. A flap or a single zip across the top only covers the opening.
• Read the zip details - look for a stated IPX rating and ends that are moulded and sealed, not cut.
• See what each rating covers - a rating on the pockets tells you nothing about the main compartment, and vice versa.
• Try the air test - roll and seal the empty bag with air inside, then press gently. If it holds pressure, the closure and welded body are sealing. It's a good field check, not a substitute for a formal water test.

Choosing Between the 2L, 25L and 40L

POD makes three waterproof bags, and each one carries a different load.

• 40L Waterproof Backpack - the full gear carry. A wetsuit, fins, towels and clothing fit in one bag, and two waterproof front pockets cover most of the front face. Rolled and sealed, it measures 56 x 33 x 17.5 cm, within most airlines' carry-on size limits.
• 25L Waterproof Backpack - the everyday carry for a single session. It takes one bulky item, a wetsuit, a pair of fins or a towel, plus your essentials. A spring suit packs far smaller than a full steamer, so check which you'll carry.
• 2L Waterproof Cross Body Bag - phone, keys and wallet in an IPX8 bag you wear across your body, where you can see and reach it.

Both backpacks have ventilated padded shoulder straps with a 1680D polyester surface, an adjustable chest strap and a mesh back panel that keeps the pack off your back. The 40L adds wider, deeper straps and a moulded carry handle for heavier loads. The full range, including bundles with POD fins and handboards, is in POD Waterproof Backpacks.

Care and Storage

• Rinse after saltwater use - freshwater and a soft cloth remove salt and sand. Mild soap lifts grime, but rinse it all away, because soap residue attracts dirt.
• Keep the zips moving - rinse salt and grit from the zip teeth, then apply a silicone zip lubricant from time to time so they run smoothly and don't seize.
• Dry it in the shade - hang the bag upside down in a well-ventilated spot. Direct sun breaks down PVC over time.
• Store it dry and empty - a damp bag grows mould. Take out sharp objects and anything with a battery, which can damage the material or, in the worst case, catch fire in storage.
• Leave the closure loose - store it unrolled with the straps slack, so the material isn't held under stress.

Questions Customers Ask

Can I swim with a waterproof backpack?

The backpacks handle rain, spray, waves and a brief accidental dunking when rolled and sealed. They aren't built to swim with or to hold gear underwater for any length of time.

Will a waterproof backpack float?

Yes. Rolled and sealed, the 25L and 40L hold their air even when you squeeze them hard, so a bag dropped in the water or knocked overboard floats with your gear dry inside. Very heavy contents reduce how high it sits. It isn't a certified flotation device, so never rely on it to keep a person afloat.

Can I put wet gear inside?

Yes. The seal works both ways, so a wet wetsuit stays in the bag and off your car seat. Take it out and dry it once you're home, because wet gear sealed in for days can grow mould and smell.

How full can I pack it?

Leave enough material above your gear for three full rolls. If you have to force the closure, the bag is too full to seal.

Can I carry a laptop in it?

Yes, in the main compartment, which has the room for it. Use a padded sleeve to protect it from knocks.

Waterproof Is a System, Not a Label

A bag keeps water out only when the material, seams, closure and zips all hold. Check each of those, read what the rating covers, and you'll know whether a backpack will keep your gear dry before you find out the hard way.