fresh water vs freshwater

fresh water

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

freshwater

noun
  • A body of fresh water 

adj
  • Consisting of fresh water. 

  • neoclassical, in reference to U.S. macroeconomics and economics departments near the Great Lakes. 

  • Unskilled as a seaman. 

  • Living in fresh water. 

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