The no black soot in tailpipe = OK was only valid on leaded fuel cars and modern ( 90's + ) feedback fuel injection cars. Lead would coat the exhaust leaving it gray, with modern FI fuel control is tight enough the tail pipe won't get black.

Water from the exhaust is a byproduct of combustion, and is one reason why it is a bad idea to start a car for 10 min on a regular basis then shut it off.