Water ratings come in two families. IP codes, defined by IEC 60529, appear on phones, earbuds and many watches. Watch water-resistance ratings, given in ATM, metres or as WR, follow ISO 22810. Both are laboratory tests under set conditions, often in fresh water. Neither means "waterproof forever": heat, soap, pressure, knocks and age all wear the protection down, and liquid damage is commonly excluded from warranties. Here is how to read them and what they leave out.
Reading an IP code
The IEC explains that an IP code has two numerals. The first rates protection against solid objects, from 0 (no protection) to 6 (no ingress of dust). The second rates protection against liquids, from 0 (no protection) to 9 (high-pressure hot water from different angles). Brands write an X in the position they are not rating: Sony's IP table, for example, lists dust levels as IP0X to IP6X and water levels as IPX0 to IPX8, and Apple rates its Ultra 3 watch IP6X for dust under IEC 60529 while stating its water resistance separately under ISO 22810. So IPX4 tells you about splashes and nothing about dust.
| Code | What the test represents (Garmin's definitions) | Garmin says it suits |
|---|---|---|
| IPX4 | Splashing water from all angles for up to 5 minutes | Splashes, light rain or snow |
| IPX7 | Incidental immersion up to 1 m for up to 30 minutes | Splashes, rain or snow, showering |
| IP68 / IPX8 | Submersion beyond 1 m; the exact depth is defined by the manufacturer | Temporary submersion |
| IP6X |