That's the $64,000 dollar question. There are many researchers working on who Erastus's father was. We do suspect that he is from a family that moved from Beaufort County NC. There were three or four Waters's who moved to southeast GA about the same time. The names that moved were John, Thomas and Issacc. I, personally, only have hard evidence back to Erastus, born in 1809.
Check out on Ancestry.com "Waters of Bulloch,GA". A cousin, Gregg Waters, maintains the site and it is very extensive. Gregg believes Erastus's parents were John Frank Waters and Milly Green. I tend to believe he is right. John's father is supposedly John Calvin Waters, born in 1740 in Marion Co. SC, son of John W. Waters of Beaufort Co. NC. That's about as far back as it goes, right now. I am thinking about submitting DNA to see if we can link back to very early Waters in England/Wales for which there are DNA markers..