fresh water vs springwater

fresh water

noun
  • Water with a very low content of dissolved salt, as opposed to brackish water or salt water. 

springwater

noun
  • Water that is purportedly, and marketed as, originating from a spring, but is mostly or entirely filtered or tap water. 

  • Water originating from a spring. 

How often have the words fresh water and springwater occurred in a corpus of books? (source: Google Ngram Viewer )