The terms "water resistant"/"waterproof" are not concrete, so the environmental waterproofing rating of enclosed electronic equipment is codified formally by tests specified by the International Electrotechnical Commission (IEC) Standard 529:
- IPX0 - Ordinary use; no water resistance tested
- IPX1 - Protected against vertically falling water drops
- IPX2 - Protected against vertically falling water drops when enclosure tilted up to 15 degrees
- IPX3 - Protected against spraying water
- IPX4 - Protected against splashing water
- IPX5 - Protected against water jets
- IPX6 - Protected against powerful water jets
- IPX7 - Protected against temporary immersion in water
- IPX8 - Suitable for continuous immersion
For all weather outdoor equipment, e.g.
GPS or Surveying equipment, an IPX rating of 4 or better is essential.