Home / Blog / Dry Bag Answers

IPX6 vs IPX7 for Dry Bags

The decision before the definition

Start from exposure, not from the number. If the worst realistic event is a bow wave, rain driven at 40 km/h, or a swimmer splashing a deck bag, then IPX6 is the honest requirement and anything more is insurance you will not claim. If the worst realistic event is the bag going over the side, being dragged under a hull, or sitting in a swamped cockpit, then IPX7 is the floor.

Price differences between the two are usually smaller than people assume, because the expensive part of a waterproof bag is the seam method, not the final grade. A radio-frequency welded construction tested to IPX7 against a stitched and taped construction tested to IPX6 can sit within 10 to 15% of each other at retail, which makes reaching for the higher figure the more durable choice in most purchases.

What the second digit is telling you

In the IP code published as IEC 60529, the first digit covers solid ingress and the second covers liquid ingress. A dry bag listing writes X for the first digit because nobody bothers testing dust protection on a bag, hence IPX6. That X is not a blank or a missing result; it simply means no claim was made, and it should not be read as a weakness.

The number after X identifies which apparatus the item survived, in conditions defined by the standard. It is a pass or fail against a described test, not a continuous score. The IEC maintains the definitions, which is why any listing worth trusting names IEC 60529 alongside the code rather than presenting six (numbers) as a rating invented in-house.

Inside the IPX6 apparatus

The jet rig is physical and unforgiving. Water is delivered at 100 litres per minute through a 12.5 mm nozzle from a distance of roughly 2.5 to 3 metres, for at least one minute per square metre of enclosure surface and not less than three minutes total. The bag is supported normally, usually upright, and every face that could meet spray is presented to the jet in turn.

What fails under that rig is rarely the fabric. A 0.5 mm TPU laminate has no difficulty with water arriving at speed; what fails is geometry at the closure and at any point where two panels meet. A jet hitting directly at the roll line can drive water past a two-fold closure that would sit happily through steady rain for an hour, which is why three folds and a buckle that pulls laterally both matter.

Duration of exposure matters as much as violence when you judge what you need. A commuter bag meets rain for forty minutes a day, five days a week, which adds up to more than 170 hours a year of persistent low-level assault. A sea kayak bag may see three minutes of genuine immersion a month. Read the specification against what your own year actually looks like rather than the worst story you have heard.

Inside the IPX7 apparatus

Immersion testing is quieter but asks a different question. The bag is submerged so that its lowest point sits around one metre below the surface and the highest point is at least 150 mm under water, held there for thirty minutes. Water temperature is controlled within a few degrees of ambient so that the air inside does not contract and fake a leak path.

Immersion punishes the things jets do not see. Pinhole-sized weld defects that a jet would miss become active conduits under sustained hydrostatic pressure. Any closure that relies on folded panels being compressed together under their own stiffness works less well when there is no dynamic force pushing contact together, which is precisely why some bags only perform when lashed tightly.

Why one grade does not imply the other

This is the single most useful fact in the whole comparison. A bag can survive thirty minutes underwater and fail a three-minute jet, because immersion applies uniform, low-velocity pressure that lets a flexible closure settle into a seal, while a jet applies high local velocity that lifts a poorly supported fold. Conversely, a bag that shrugs off a jet can slowly take water over half an hour at depth through a weld imperfection.

Reputable listings therefore say IPX6/IPX7 or IPX8 rather than the higher number alone, which tells you both rigs were passed. If only a single code is printed and no IEC reference appears, assume one test was run and pick the grade that matches how you use the bag. Our full rating guide covers the wider family including IPX5 and IPX8.

Mapping activities to a grade

Think about the worst event you would still consider ordinary. A commuter walking through a storm expects rain arriving sideways but does not expect the bag to fall into a harbour; IPX6 fits. A whitewater paddler expects the bag to be upside down in a hole for a few seconds several times a day; IPX7 fits, and arguably IPX8 with a documented depth would be better.

Then consider duration. A capsize in 1 metre of water that takes thirty seconds to recover is comfortably covered by IPX7 with margin. A bag dragged behind a boat at 6 knots for ten minutes is not covered by either code, because dragging creates pressure and abrasion that no ingress test models. In that case the construction matters more than the grade: heavier film, a reinforced base and a protected closure.

Seam construction behind each code

There is no route to a credible immersion grade through a needle. Every stitch hole is a capillary, and under sustained pressure those capillaries feed. That is why the bags that honestly claim IPX7 use radio-frequency or hot-air welded seams, where two film surfaces fuse into a continuous bond without any hole through the membrane.

Bond quality is expressed in countable terms by anyone serious about the claim: typically 200 to 300 N of peel strength across every 25 mm of bond width, quoted with a method attached. The ASTM publishes standard peel and tensile procedures that make those figures comparable between sellers, so ask which procedure sits behind a claim before trusting it.

Jets are slightly more forgiving of stitched and taped seams, because a short-duration directional event may not have time to drive water through a well-taped line. It is still a compromise. If a listing quotes IPX6 and the photographs show stitching rather than a continuous weld, expect that bag to gain a little moisture over a long outing; see our notes on seam construction before buying.

What thirty minutes underwater really does

Immersion introduces hydrostatic load that grows with depth: roughly 0.1 bar for every metre, so one metre is about 10 kPa of uniform pressure across every square centimetre. That is not dramatic, but it is relentless and it acts for half an hour. Anything relying on friction between folded faces is being asked to hold indefinitely rather than to rebuff a moving jet.

Air inside the bag complicates matters further. If the bag is packed loosely with trapped air, internal pressure partially balances the outside load, and that air escapes through any defect it finds. If the air has been purged, the panels compress and contact area increases, which usually helps. This is the mechanism behind our write-up on pressure differentials and it explains why two users get different results from the same bag.

How a bag loses the grade it earned

A rating describes a new bag on the day of testing. Creasing is the main mechanism of decline: repeatedly folding a TPU film in exactly the same place creates a stress-whitened line, and after a few thousand cycles that line becomes a genuine leak path. Storing a bag rolled tightly for months does the same thing faster than using it does.

Two other factors accelerate the slide. Abrasion thins the film from outside, most often at the base of a bag that meets a boat deck, a board or a gravel car park every weekend. Then there is contamination: sunscreen, DEET-based insect repellent and some oils plasticise the surface and reduce its ability to hold a flat contact at the fold. None of these appear in the standard, all of them appear in the field.

Testing both codes at home honestly

1. Close the bag with three folds and the buckle pulled laterally, then listen for a hiss while squeezing.
2. For the jet check, use a garden hose on a jet setting for three minutes from about 2 metres.
3. For the immersion check, fill a bath and submerge the bag with a weight, not your hand.
4. Put dry tissue inside before each test so a trace of moisture is visible immediately.
5. Dry the outside fully before opening, otherwise you will misread drainage as leakage.

The home version approximates rather than replicates, and every step above has a known source of error. A hose jet at domestic pressure delivers far less than 100 litres per minute, so a pass is meaningless. A bath gives only 300 to 400 mm of depth rather than a metre. What home testing does reliably is compare one bag against another and catch a closure failure before a trip; see the full home method for the detail.

Reading a listing that only says waterproof

• Look for the standard name, IEC 60529, next to any code rather than a bare number.
• Check whether both grades are claimed; IPX6/IPX7 means two separate rigs were passed.
• Look for the depth or nozzle figure in the fine print; a real test result includes them.
• Check the seam method in the photographs: continuous welds, not stitching.
• Beware any claim of a permanent rating with no time or depth qualifier attached.
• Compare against a model with a documented result elsewhere on the same page.
• Treat IPX8 with care unless the depth and duration are printed next to it.

Two phrases carry most of the signal. First, whether the seller says which evidence exists and offers it on request; a test report with a date, a sample description and a rig description is worth more than any adjective. Second, whether the listing acknowledges limits at all, since a company confident in its own result also tells you what would invalidate it.

Which one to put in the basket

Choose IPX7 unless the bag will never leave the deck or the rack. It costs a little more, it covers the accident that actually ruins trips, and it implies a construction standard that survives abrasion better. Choose IPX6 for motorcycle luggage, dry storage in a cabin, or any use where falling in the water is not part of the plan.

Then protect the grade you bought. Roll three times, vary the fold line weekly, rinse the closure before closing, and store the bag loosely with the buckle undone. Those four habits decide whether an immersion-rated bag still passes its own standard in year five, and they cost nothing compared with replacing gear because a bathroom test failed a week too late.

Sealed devices and dry bags are not the same test

Shoppers often transfer intuition from phone cases, where IPX7 and IPX8 are everyday claims. Those products are rigid enclosures with gasketed ports and precise tooling; their test result depends on geometry that never changes. A dry bag is flexible, its seal is created by the user each time it closes, and the result therefore depends on how it was packed.

That distinction is why a 20L model can pass an immersion rig in a laboratory and still take water in real use. The variable is the roll, and the person doing the packing controls it. Read the technique notes in closure guide, then check you are following them with two numbers in mind: three folds and no air trapped inside.

If you need the level of assurance that a rigid enclosure provides, put the item in a smaller roll-top inside the main bag. Two independent seals convert a user-dependent result into a largely user-independent one, which is the reason expedition paddlers double-bag electronics. Start from the roll-top dry bag range if you want one closure geometry across every size, and check answers to common listings questions in the site FAQ before you compare quotes.