William Ingham, civil engineer, was the son of Joshua Ingham, himself an engineer, and his wife Nancy. He attended evening classes at the Technical School in Burnley, completed a five year apprenticeship in mechanical engineering under his father, and later an apprenticeship in civil engineering with the borough surveyor of Burnley. In 1891 he was appointed assistant water engineer to the Plymouth Corporation and later became resident engineer on the Burrator Water Works for that town. In 1896 he was appointed water engineer to the borough of Torquay and was involved in the design of several water works and related tasks. In 1899 he published a paper on "The incrustation of iron pipes at the Torquay Water Works" in the Proceedings of the Institution of Mechanical Engineers. He was a member of the (British) Institution of Civil Engineers and the Institution of Mechanical Engineers. In 1893 he married Isabel Hindle, with whom he had two sons and two daughters.
Ingham came to the Cape Colony in June 1903, having been selected to design and carry out a water scheme for Port Elizabeth. The project included a large reservoir on the Sand and Bulk rivers and was completed in November 1907. The loyalty he inspired in his staff is shown by the fact that most of his assistants in England followed him to South Africa. He described the work in "The new water works for Port Elizabeth, South Africa", a paper delivered before the South African Association for the Advancement of Science at its meeting in Grahamstown in 1908. A summary of the paper was published in the association's Report for that year (pp. 74-75). After a visit to England he was in private practice as a consulting water and irrigation engineer at Port Elizabeth for some time. In May 1909 he delivered a paper on "Irrigation, with special reference to pumping plants" at the First South African Irrigation Congress. The paper was published in the congress Proceedings (Cape of Good Hope, 1909). Later that year he became resident engineer at the Smartt Syndicate irrigation works at Britstown, but in October 1910, before the work was completed, he was appointed chief engineer to the Rand Water Board, a post he held until his death in 1924.
After considering various possible water schemes for Johannesburg Ingham chose building the Vaal River Barrage, with a pumping and filtration works near Vereeniging. This carefully designed and well constructed scheme was started during World War I (1914-1918) and was completed in 1923. He also acted as consulting engineer to many municipalities and other clients, and was widely regarded as a brilliant engineer.
Ingham participated actively in the proceedings of several professional societies. He was a council member of the South African Society of Civil Engineers by 1913, serving as president in 1920. His presidential address was devoted mainly to hydraulic engineering, particularly the Vaal River water scheme, but he also expressed himself in favour of the formation of a joint secretariat for the engineering and technical societies of South Africa. He was president of the South African Institution of Engineers for 1915/6. In 1913 he joined the South African Association for the Advancement of Science and at its meeting in Mozambique that year contributed "A few notes on water divining". He served as president of Section A of the association in 1919. His presidential address, "The Vaal River and its possibilities", dealing mainly with water supply from the river's catchment area and its rainfall records, was published in the association's Report for that year (pp. 17-41). For five years he was chairman of the South African branch of the British Municipal and County Engineers. Shortly before his death he was elected president of the Associated Scientific and Technical Societies of South Africa. For five years he was an examiner in engineering for the University of the Witwatersrand.
Ingham published many reports and papers on waterworks, irrigation schemes, water conservation, and afforestation. For example, "Pumping and irrigation" (Agricultural Journal of the Union of South Africa, 1909), "The pumping and purification plant at the Springs Pumping Station, Rand Water Board" (1915) and "Vaal River scheme, service reservoirs recently constructed by the Rand Water Board", both in Civil Engineering= Siviele Ingenieurswese .
The day before his death he was informed that the University of the Witwatersrand wished to confer on him an honorary Doctor of Science (DSc) degree.