Watt died in Bournemouth, Dorset on 28 September 1897. He was survived by three of his five sons and five daughters, the youngest son was Oswald Watt, a celebrated aviator. Another son, Ernest Watt, became the father-in-law of Sir Laurence Whistler Street when he married Ernest's daughter Susan Gai Watt, herself the first female chair of the Eastern Sydney Health Service (now amalgamated with Illawarra).
