|Died||15 June 1905 71) (aged|
|Resting place||Hampstead Cemetery|
|Projects||Claymills Pumping Station, Hury Reservoir, Elan Reservoirs/Elan Aqueduct|
His most famous projects were:
- Elan Valley Dam and Elan aqueduct for Birmingham Corporation Water Department, England (water supply).
- Hury Reservoir for Stockton and Middlesbrough, England (water supply).
- Abbeystead Dam, one of the first stone-faced concrete dams.
- Werribee sewage works and farm for Melbourne, Australia.
- Claymills Pumping Station for Burton upon Trent, England (sewage disposal).
- Laid out parts of Ramsey, Isle of Man (drainage).
He became a member of the council of the Institution of Civil Engineers in 1884, vice-president in 1895 and was elected to the chair of the institution from November 1900 to November 1901.
He became the elected chairman of the Engineering Standards Committee, when it was formed in 1901 from a combination of organizations, which later became the British Standards Institution. He served as High Sheriff of Radnorshire for 1901.
He was elected a Fellow of the Royal Society in 1901. His candidature citation read:
President of the Institution of Civil Engineers. Author of 'Lectures on Water Supply, Prospecting for Water, Prospecting and Boring' delivered at the School of Military Engineering, Chatham, also of 'The Supply of Water to Towns,' and other works. The designer of the waterworks and sewerage of Lancaster, Lincoln, Stockton, Middlesbrough, Rotherham, Southport, Burton-on-Trent, Melbourne (Australia), Birmingham, and many other towns. These designs include some of the largest schemes of water supply, sewerage or sewage disposal for Halifax, Herford, St Helens, Darlington, Whitby, the Potteries, Derby, Southampton, Durham, Shrewsbury, Malvern, Cambridge, Edinburgh, Plymouth, York, Antigua, Philadelphia (US), and other places. Was a member of the Royal Commission on Metropolitan Water Supply. Eminent as a hydraulic engineer.
In March 1903 he received the honorary freedom of his native town of Lancaster
He died at 51 Fitzjohn's Avenue, Hampstead, London and was buried in Hampstead Cemetery.
- ""THE BIRMINGHAM WATERWORKS." Lecture by JAMES MANSERGH, President of the Congress". International Engineering Congress 1901 : Glasgow. Report of the proceedings and abstracts of the papers read. 1901.
- "Abbeystead Dam". Engineering Timelines. Retrieved 31 January 2017.
- Watson, Garth (1988), The Civils, London: Thomas Telford Ltd, p. 252, ISBN 0-7277-0392-7
- "No. 27293". The London Gazette. 12 March 1901. p. 1761.
- "Certificate of Candidature for Election". Library and Archive catalogue. Royal Society. 6 June 1901. Archived from the original on 19 October 2018. Retrieved 19 October 2018.
- 1898 Official Guide to Isle-of-Man
- Elan Valley
- Claymills Archives
- Report of a 1901 lecture by James Mansergh, on the Elan Valley scheme
|Professional and academic associations|
| President of the Institution of Civil Engineers
November 1900 – November 1901