“I bought powdered water, but I don’t know what to add to it”

“Just add water” is a popular direction on simple recipes or product instructions. “I bought powdered water, but I don’t know what to add to it” is a joke that has been told by several comedians.
 
“Red Skelton swears he just invented something called powdered water: all you do is add water” was cited in print in 1964; Red Skelton (1913-1997) was a popular American comedic entertainer. “I bought some powdered water, but I don’t know what to add to it” was credited to American comedian Steven Wright in 1985.
 
   
28 August 1964, Marietta (GA) Daily Journal, Mike Connolly column from Hollywood, pg. 2B, col. 4:
RED SKELTON swears he just invented something called powdered water: all you do is add water.
     
Google Books
The Collected Stories of William Humphrey
By William Humphrey
New York, NY: Delacorte Press/Seymour Lawrence
1985
Pg. 308:
“Water. Powdered water. Dehydrated. When you’re ready to use it you take and mix it with a little water. They say it makes a pretty fair substitute. Tastes a little flat, they say, but does all right for mixing.”
 
4 February 1985, Trenton (NJ) Times, Frank Tyger column, pg. A2, col. 2:
“I bought some powdered water,” says Steve Wright, “but I don’t know what to add to it.”
 
Google Books
No Hang-ups III
By John Carfi, Cliff Carle and Greg Tenorio
Chatsworth, CA: CCC Publications
1988
Pg. 63:
I just bought some powdered water and I’m not sure what to add.
 
Google Books
What a College Senior Should Know When the Barrel Is Empty and the Party Is Over
By Charley Swayne
La Crosse, WI: Charley Swayne
1994
Pg. 72:
If you have powdered water, what do you add to it?
 
Twitter
Schwartz Koph
‏@schwartz_koph
I bought powdered water but I don’t know what to add to it.
7:55 AM - 22 Sep 13