An account of how a city's water supply is purified. Each stage of purification in a filtration plant is shown, together with the complex system of underground mains serving all parts of the city. The safeguarding of water supplies on common carriers (trains, ships, aircraft) through regular government laboratory analyses is illustrated. The film closes with a glimpse of developments in the treatment of water supplies, including the addition of fluorine.

More info on this film in NFB catalogue »»