Perhaps the most important and influential figure in water towers (and in Civil Engineering in general) was the incredibly prolific Louis Gustave Mouchel.
Both Gawthorpe and Newton le Willows were built by his firm after he introduced 'ferro-concrete' to Britain. This was one of the most influential and far-reaching inventions to shape 20th century civil engineering.
The engineering timelines website has a special feature on his life and work.
Incredible to think he did what he did in just eleven years before dying of stomach cancer at 56.