He was educated at Bancroft"s School in 1894-1900 and then at the University of London.
He was killed on the first day of the Battle of the Somme, in World War I, while serving as a second lieutenant in the 2nd Bn Essex Regiment. A volume of his poems Rail-Head and other poems (including the poems Rail-Head and Bivouacs) was published posthumously in 1916. At the time of the United Kingdom 1901 national census, the family were living in East London, where Gilbert"s occupation, aged 18, was given as a ship"s Draughtsman.
He later qualified as an architect (Royal Institute of British Architects) and gave his profession as "architect-surveyor" when he enlisted in the army on 8 September 1914.
Waterhouse enlisted as a private, aged 31, in the 18th Battalion Royal Fusiliers. He applied for a commission in April 1915, and became an officer in May 1915, when he was posted as a second lieutenant to the 3rd Battalion Essex Regiment at Harwich, a training unit for officers and soldiers.
His sonnet "Coming in splendour thro" the golden gate" appeared in The English Review in October 1915. lieutenant is not known when he was posted to 2nd Battalion Essex Regiment in France, but National Archive contain a telegram to his father, dated 25 February 1916, stating that Waterhouse has been "admitted to Number 3 General Hospital Le Treport 22 February suffering from septic left arm, slight." Waterhouse returned to his unit, the 2nd Battalion, The Essex Regiment, at some stage prior to the Battle of the Somme.
This Battalion was part of the 12th Brigade of the 4th Infantry Division On 1 July Waterhouse was serving with C Company.
His unit was stationed in the line south of the village of Serre. At the start of the assault the 2nd Bn had comprised 24 officers and 606 other ranks. By the end of the day it was decimated and finished it with only two officers and 192 other ranks unscathed.
Waterhouse was initially posted "wounded and missing".
His personal records are available in the United Kingdom National Archives and it is clear from survivor testimony that he either died of wounds or was killed after being initially wounded and cared for by his servant. However he was not formally pronounced dead until March 1917, leaving his family in some anguish and forlorn hope he may have been taken prisoner.
From Pte J Adkins 15951 Street John"s Hospital Etaples 11 July 1916: His body was not recovered until after the battle, when he was buried in the CWGC Serre Road Number.2 cemetery around July 1917.