“Waterproof” is not a specification. It is a marketing adjective, and in most jurisdictions manufacturers are careful never to claim it in the legal text while implying it everywhere else. What the text says instead is “water resistant” — followed by a code that consumers are expected to decode.
The two rating systems, decoded
IP ratings — the “IP67” and “IP68” on your phone's spec sheet — are laboratory codes for ingress protection. The second digit is the water story: 4 is splashes, 5 is jets, 6 is immersion. An IP68 rating means the device survived a specific depth for a specific time in fresh water, in a lab, stationary, new.
- IPX4 — splash resistant; rain, sweat, the odd spill
- IPX5/6 — jets and heavy spray; showers, kitchen taps
- IP67 — brief immersion, roughly a metre, roughly half an hour
- IP68 — deeper, longer; the manufacturer must state the depth
Watchmakers quote a different system: metres of “water resistance” that are not swimming depths but pressure tests. A 30-metre-rated watch is splash-proof; a swimmer needs 100 metres on the dial, and a diver needs the ISO diver certification behind it.
What the ratings quietly exclude
The exclusions are where warranties live. Standard IP tests use fresh water; chlorinated pools and seawater attack seals faster. Tests are done with intact gaskets; a device that has been dropped or opened for repair is no longer the device that was tested. Hot water, soap and steam defeat seals designed for cool immersion — the shower is harder on earbuds than the rain. And ratings describe new products: seals age, and the second year of ownership is not the first.
The buyer's practical rules
Buy one rating class above your real use, and treat the rating as the immunity it is: a specification with conditions. If the product's advertising shows it in a pool and the warranty excludes liquid damage, believe the warranty — it is the only sentence in the box that was written by lawyers.