Son of Samuel and Sarah Ann Hewitt of 7 Garden Street, Blaydon on Tyne, Co Durham (late of Hamsterley Colliery, Co Durham) and later, of Barlow, Co Durham. Two sisters: Mary and Elizabeth. Brothers: John and Joseph. William's brother, Private John Cousins Hewitt, 13306 11th (Pioneer) Bn Durham Light Infantry, was killed in action in France on 11th February 1916 and buried in Ferme-Olivier cemetery, France (as reported in the Blaydon Courier, 19th February 1916). William's father, Samuel, died on 9th December 1922, aged 63. His mother, Sarah Ann, died on 15th September 1929, aged 78. Joseph died in Canada in 1926. His sister Mary had died on 21st December 1912, aged 19. Elizabeth married Robert Ripley and died on 28th April 1953, aged 57.