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.