Apple started dabbling in water resistance with iPhone 6s, using gaskets and seals to protect against accidental splashes and dips. (imore.com)
Rated IP67, they can survive accidental splashes, dunks, and floods, but isn't rated as highly as some competing phones from Samsung and others. (imore.com)
So accidental splashes are fine, but do not immerse it in water. (techtree.com)