This is excerpted from a New York Times article.
“For its recent Galaxy devices, Samsung touts “an international standard rating of IP68” and says the Galaxy S7 and later models are “deemed fit enough to withstand dust, dirt and sand, and are resistant to submersion up to a maximum depth of 1.5 meters underwater for up to 30 minutes” — which should protect it from the dreaded Toilet Drop.
As for those numbers, the first digit in the rating refers to the level of protection from solid substances and is measured on scale of 0 (no protection) to 6, with a 6 meaning no dust enters the device for two to eight hours of exposure. The second number refers to water and is measured on a scale of 0 to 9. A rating of 8 designates protection against water immersion under pressure for long periods, and a 9 rating means the object can also hold up against high-pressure water jets.”