flush toilet vs washroom

flush toilet

noun
  • A toilet that uses water to flush urine and feces through a pipe to another location, typically a sewer main in urban settings or a septic tank elsewhere. 

washroom

noun
  • A room with a toilet, particularly a public toilet. 

  • A room intended to wash the face and hands. 

How often have the words flush toilet and washroom occurred in a corpus of books? (source: Google Ngram Viewer )