A submersion test seals a dry bag, usually with an absorbent marker inside, and holds it underwater for a set time to confirm the seal under pressure. It is the test that backs up IPX7 and IPX8 claims.
People searching for "dry bag submersion test" usually want a direct, practical answer - and this page delivers one. This guide explains dry bag submersion test ratings and how waterproofing is actually tested, so you can read a spec sheet and a test report with confidence instead of trusting a label.
Setting up the test
Place a paper towel or dry fabric inside, seal the bag, and submerge it fully with a weight to keep it down. The depth and time should match the claimed rating.
Reading the result
A dry interior after the soak means the seal held; any moisture means a leak at the roll, zipper or seam. Repeat at the rated depth for a fair verdict.
Why depth matters
Water pressure increases with depth, so a bag that passes at the surface can leak at two meters. Test at the depth the bag claims.
What to ask a supplier about testing
Before you trust a dry bag submersion test, ask for the test report, the standard used, the depth and duration for any IPX8 claim, and the production batch sampling plan.
Written answers are better than verbal ones. A dated report that matches your product and material is the evidence your brand and customers need.
How the IPX scale works
The IP scale uses two digits: the first rates solids from 0 to 6 and the second rates liquids from 0 to 8, with X meaning the digit was not tested. A dry bag submersion test only concerns the liquid (second) digit.
The key levels for dry bags are IPX6 (powerful water jets), IPX7 (30 minutes at 1 meter) and IPX8 (continuous immersion beyond 1 meter under stated conditions). Higher is not automatically better without the test context.
How factories test waterproofing
Factories test a dry bag submersion test with submersion jigs, inflation-and-submersion to reveal air bubbles, and seam pull tests. A paper-towel test inside the bag after immersion is a simple, reliable verification.
Third-party labs can certify IP ratings with controlled equipment. For production, ask for the batch testing plan - typically AQL sampling plus a leak test on every batch - rather than a single prototype certificate.
What rating you actually need
For kayaking, rafting and any chance of submersion, a dry bag submersion test should meet IPX7 or IPX8. For casual beach, travel or commuting where only splashes and rain occur, IPX6-level protection may be enough.
Match the rating to the real risk. Paying for IPX8 in a beach tote is unnecessary, while trusting an IPX6 bag in a kayak hatch is risky. The right rating is the one that matches your water exposure.
Rating vs real-world performance
A dry bag submersion test rating is a controlled test, not a promise for every situation. A bag that passes IPX7 in the lab can still leak if it is overpacked, the closure is dirty or the seam is damaged.
Treat the rating as a baseline and protect against the gaps: close the bag correctly, inspect seams and closures, and re-test periodically. Real-world care extends what any rating delivers.
Reading a test report
A credible dry bag submersion test test report states the standard, the test conditions, the sample and the result. Check the date and that the report matches the product and material you are buying.
For OEM buyers, ask for the test report before bulk and keep a copy with your compliance documents. A dated, matching report protects both your brand and your customers.
| Factor | Detail |
|---|---|
| Marker | Paper towel |
| Depth | Match rating |
| Time | Match rating |
| Rating | Protection | Typical dry bag use |
|---|---|---|
| IPX6 | Powerful water jets | Splash and rain protection |
| IPX7 | 30 min at 1 meter | Kayaking, brief submersion |
| IPX8 | Deeper / longer immersion | Expedition, sustained water |
| IP68 | Dust-tight + immersion | Beach, dust and water |
| Check | What to look for |
|---|---|
| Test standard | IPX7 / IPX8 with stated conditions |
| Depth & duration | Must be stated for IPX8 |
| Report | Dated, matching the product |
| Batch testing | AQL sampling plus leak test |
| Seam test | Seam strength test result |
| Test | What it checks | How |
|---|---|---|
| Submersion | Water ingress | Immerse under pressure |
| Inflation | Tiny leaks | Air bubbles in water |
| Seam pull | Weld strength | Pull seam to failure |
| Zipper | Closure seal | Water pressure on teeth |
| Claim | What it means |
|---|---|
| IPX6 | Resists powerful jets |
| IPX7 | 30 min at 1 meter |
| IPX8 | Deeper/longer, as specified |
The factory submersion test protocol
The standard proof test for a dry bag is the submersion test: seal the bag, inflate it slightly to pressurize the seams, submerge it in a water tank to 30 to 50 cm depth for 30 to 60 seconds, and watch for bubbles. A continuous stream of bubbles at a seam or the closure means a leak; a single bubble on first dunk is usually trapped air and is fine on second dip.
At a working dry bag line, every single bag is inflation-tested before packing - that is a 10-second per unit step. Bulk lots also undergo a random submersion dip at AQL inspection. The test catches pinhole welds that visual inspection misses.
What real submersion rating means
Retail bags rarely state a submersion depth, and with good reason: a roll-top bag is rated for splash, spray and brief immersion, not for 10-meter diving. A roll-top that survives a 1-meter, 30-second dunk is doing its job. Bags marketed as 'submersible' to 5 meters need a clamp or zipper closure, not a roll-top, because a roll will float open under pressure.
If a buyer needs true dive-rated waterproofing, they should look for a zip-seal or clamp closure rated to IP68 and tested to IEC 60529. A roll-top at IPX6 or IPX7 is the honest specification for 99 percent of outdoor use.
Home test for end users
Tell your customers to test a new dry bag before packing valuables: stuff a paper towel inside, seal it, submerge it in a bathtub for 5 minutes, then check the towel. If it is dry, the bag is good. This one instruction reduces warranty claims by giving users confidence and catching defective bags early.
Lab vs in-house testing
An outside lab (SGS, Intertek) charges $300 to $800 for a formal IPX test with a report. An in-house submersion tank costs the factory $2,000 to $5,000 to build and runs 100 percent inspection on every unit. For a buyer, the in-house test matters more - it catches every bad bag, not just the sampled ones.
Submersion vs inflation testing
Two tests catch leaks: inflation (blow the bag up to 3 kPa, feel for escaping air) and submersion (dip the inflated bag and watch for bubbles). Inflation is faster - 3 seconds per bag - and catches pinholes. Submersion is more reliable - it shows exactly where the bubble comes from. Factories should do both: inflation on 100 percent of units, submersion on a sample.
For a buyer, ask for the test protocol in writing. If the factory says 'we just look at it', walk away. A leak that looks fine dry will show up underwater. The 10-second submersion dip is the cheapest insurance in the whole process.
Home test for end users
Teach customers the paper-towel test: seal a dry paper towel inside, submerge for 5 minutes, check. If the towel is damp, return the bag. This one instruction reduces warranty claims by giving users confidence and catching defects early. Print it on the hang tag.
Test once a season, because seals degrade. A bag that passed last year may have a weak buckle or a lifting seam this year. The 5-minute test is cheaper than a water-damaged phone.
Factory test cost
An in-house submersion tank costs $2,000 to $5,000 to build. Per-bag inflation test is 3 seconds, free. Per-bag submerge dip is 10 seconds, free. The in-line test catches 99 percent of leaks. A factory without a tank cannot verify its own welds.
Ask for the test protocol in writing. 100 percent inflation, AQL submersion sampling. The 10-second dip is the cheapest insurance in the process.
User testing instructions
Print the paper-towel test on the hang tag: seal a dry towel, submerge 5 minutes, check. This 60-second instruction catches defective bags early and cuts warranty claims. Test once a season. A bag that passed last year may have a weak seal this year.
Factory vs home test
The factory inflates and submerges 100 percent of bags. The user does the paper-towel test once a season. Both matter: the factory catches manufacturing defects, the user catches wear. The 5-minute home test is cheaper than a water-damaged phone. For brands sourcing this spec at volume, JUNYUAN BAGS manufacturing keeps the MOQ at 500 and turns pre-production samples around in 6 to 10 days.
Factory test protocol
Every bag is inflated to 3 kPa and dipped in a water tank for 10 seconds. Bubbles at a seam mean a leak. This 10-second per-unit step catches pinhole welds that visual inspection misses. Bulk lots also get random submersion dips at AQL inspection.
Tell customers to do the paper-towel test: seal a dry towel, submerge 5 minutes, check. Test once a season. The 5-minute home test is cheaper than a water-damaged phone.
Submersion test method
A submersion test checks whether a sealed bag actually keeps water out. The bag is sealed, inflated slightly to expand the seams, and lowered into a tank of water to 1 m depth for 30 minutes for an IPX7 claim, or to 3 m for 30 minutes for IPX8. Bubbles streaming from a seam, zipper or roll-top indicate a leak. The test is run on 5 samples per batch for production QC, and on 10 samples for a type-approval report. A bag that passes on the bench may still leak when overpacked, so the test uses an 80 percent packed load.
For pre-shipment inspection, AQL 1.5 applies: 0 critical leaks allowed in a sample size of 200 for a 5,000-piece order. Ask the factory for a dated test report showing the water depth, duration, sample count and result. A home test is a bathtub: fill the bag 80 percent, roll it four times, submerge it for 10 minutes, and feel the inside through the film. If any seam weeps, reject the batch. The inflate-and-listen test is a screen, not a substitute for real submersion.
People also ask
What is the difference between a dry bag and a dry sack?
They are the same product. Dry sack is the more common British and outdoor-store term, while dry bag is used more in the US.
Does dry bag material affect waterproofing?
The material supplies the waterproof barrier, but the closure and seams decide real-world waterproofing. A good film still leaks if seams or closures fail.
What is a D-ring on a dry bag?
A D-shaped metal or plastic ring used as an attachment point for straps, carabiners or lashing the bag to a boat.
Can you put a phone in a dry bag?
Yes, using a dedicated phone dry bag or a padded roll-top bag. Test the bag first and add padding for impact protection.
What is the difference between waterproof and water resistant?
Waterproof means it keeps water out under submersion or jets; water resistant means it resists light rain and splashes but will leak under pressure or immersion.
What is the difference between a dry bag and a backpack?
A dry bag is waterproof and seals shut; a backpack is structured for carry but is rarely fully waterproof. A dry bag backpack combines both.
What are the different types of dry bags?
Roll-top, zipper, backpack, tote, phone, floating, waist pack, duffel and pouch styles, each built for a different activity and access need.
What is the difference between TPU and PVC dry bags?
TPU is lighter, softer and more UV-stable; PVC is heavier, more puncture-resistant and cheaper. TPU suits premium packable bags; PVC suits rugged, high-volume bags.
Key takeaways
- Choose dry bag submersion test by fixing the activity, size, material and closure before comparing options.
- Verify waterproofing with a stated IPX rating and a real test method, not a label.
- For bulk orders, confirm MOQ, lead time and a pre-production sample before committing.
- Match material to conditions: TPU for cold and UV, PVC for abrasion, coated nylon for weight.
- A physical pre-production sample is the only reliable way to lock material, color and printing.
- Store dry bags loose and shaded, and re-test the seal before trusting them with electronics.
Related guides
- What is a dry bag?
- Dry bag materials: TPU vs PVC vs nylon
- IPX / IP68 waterproof ratings
- Types of dry bags
- OEM dry bags
Step by step
- Find the stated IPX or IP rating and the test conditions.
- Confirm the depth and duration for any IPX8 claim.
- Look for a dated test report that matches the product.
- Run your own leak test before trusting expensive gear.
Specification checklist
- Fix the specification first - material, size, closure, printing and packaging - so quotes are comparable.
- Verify waterproofing with a stated IPX rating and a real test method, and confirm the batch sampling plan.
- Order a pre-production sample and approve it before bulk production begins.
- Confirm MOQ, lead time, payment terms and the correct HS code before you commit.
- Match the material to the conditions: TPU for cold and UV, PVC for abrasion, coated nylon for weight.
- Ask for a dated test report and a pre-shipment inspection (AQL) for waterproofing and seams.
- Keep the most valuable items in an inner pouch as a second layer of protection.
- Rinse, dry and store the bag correctly to extend its lifespan season after season.
Bottom line
The bottom line is to treat an IPX rating as a claim to verify, not a guarantee to trust. A stated IPX7 or a fully specified IPX8 with a dated test report is meaningful; an unsupported IPX8 is marketing. Confirm the conditions and run your own leak test before relying on any bag. For "dry bag submersion test", this is the summary that matters most.
Frequently Asked Questions
Q1. What is the difference between a dry bag and a dry sack?
They are the same product. Dry sack is the more common British and outdoor-store term, while dry bag is used more in the US.
Q2. Does dry bag material affect waterproofing?
The material supplies the waterproof barrier, but the closure and seams decide real-world waterproofing. A good film still leaks if seams or closures fail.
Q3. What is a D-ring on a dry bag?
A D-shaped metal or plastic ring used as an attachment point for straps, carabiners or lashing the bag to a boat.
Q4. Can you put a phone in a dry bag?
Yes, using a dedicated phone dry bag or a padded roll-top bag. Test the bag first and add padding for impact protection.
Q5. What is the difference between waterproof and water resistant?
Waterproof means it keeps water out under submersion or jets; water resistant means it resists light rain and splashes but will leak under pressure or immersion.
Q6. What is the difference between a dry bag and a backpack?
A dry bag is waterproof and seals shut; a backpack is structured for carry but is rarely fully waterproof. A dry bag backpack combines both.
Q7. What are the different types of dry bags?
Roll-top, zipper, backpack, tote, phone, floating, waist pack, duffel and pouch styles, each built for a different activity and access need.
Q8. What is the difference between TPU and PVC dry bags?
TPU is lighter, softer and more UV-stable; PVC is heavier, more puncture-resistant and cheaper. TPU suits premium packable bags; PVC suits rugged, high-volume bags.
Q9. What is a purge valve?
A one-way valve that lets air escape after rolling, compressing the bag for packability.
Q10. What does IPX8 mean on a dry bag?
IPX8 means the bag survives continuous immersion beyond 1 meter under manufacturer-specified conditions. The depth and duration are only meaningful if stated.
Q11. Are dry bags safe for electronics?
Yes for water protection, but they do not protect against impact. Use a padded or dedicated electronics dry bag and test it first.
Q12. How are dry bags made?
The body is cut from waterproof film or coated fabric, seams are welded or taped, hardware is attached, and each bag is leak-tested before shipping.
Q13. What are the parts of a dry bag?
Body fabric, roll-top or zipper closure, buckle, D-rings or attachment points, straps or handles, and optional purge valve or window.
Q14. What can go in a dry bag?
Clothing, electronics, food, sleeping gear, documents, first aid kits and anything else that must stay dry around water or in wet weather.
Q15. What is a dry bag duffel?
A dry bag duffel is a large, roll-top or zippered duffel for expedition gear, often with shoulder straps and a wide opening.
Q16. How do I pack a dry bag?
Pack dense items at the bottom, soft items on top, leave fabric for the roll, and squeeze out excess air before closing.
Q17. What is a recycled dry bag?
A recycled dry bag uses recovered polyester or nylon fabric, often with a TPU or silicone coating, to reduce virgin material use.
Q18. Are IPX ratings on dry bags trustworthy?
Only when test conditions are stated and backed by a report. Many listings misuse IPX8 without specifying depth or duration.
Q19. How are dry bags tested for waterproofing?
Factories test with water submersion jigs, inflation and submersion to reveal bubbles, and seam pull tests. Third-party labs can certify IP ratings.
Q20. Are TPU dry bags eco-friendly?
TPU is generally considered more eco-friendly than PVC because it is phthalate-free and easier to recycle, though no plastic is fully green.