greatest thing since indoor plumbing

the greatest thing since indoor plumbing

A humorous and hyperbolic statement indicating one's belief that something is excellent, especially something new and innovative. These waterproof jeans are the greatest thing since indoor plumbing. I don't have to worry about getting soaked!
See also: great, indoor, plumbing, since, thing
Farlex Dictionary of Idioms.

greatest thing since indoor plumbing

 and the greatest thing since sliced bread
Rur. the most wonderful invention or useful item in a long time. As far as I'm concerned, this new food processor is the greatest thing since indoor plumbing. Joe thinks Sally is the greatest thing since sliced bread. You can tell just by the way he looks at her.
See also: great, indoor, plumbing, since, thing
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • (something) is the new (something)
  • a fast talker
  • (one) could use (something)
  • a horse of another
  • a horse of another color
  • a horse of another colour
  • a/the feel of (something)
  • (I) wouldn't (do something) if I were you
  • a slew of (something)
  • a straw will show which way the wind blows