THE WATER SUPPLY OF LONDON. 



169 



THE PRESENT WATER SUPPLY. 



At present London is supplied with water from four 

 sources — the Thames, the Lea, the New River, and deep 

 wells. Of these the deep wells yield as a rule the purest 

 water, requiring no filtration or treatment of any kind before 

 delivery for domestic use. The river waters, on the other 

 hand, require some kind of treatment before delivery — 

 storage, subsidence in reservoirs, and filtration. The water 

 from the Thames is abstracted at and beyond Hampton, far 

 above the reach of the tide and London drainage. The 

 water from the Lea is taken out at two points, viz., at Angel 

 Road near Chingford, by the East London Water Company, 



No. 2. 



and above Hertford by the New River Company, who 

 convey it to Green Lanes by an open conduit twenty-five 

 miles long, called the New River Cut, in which it is mixed 

 with a considerable volume of spring and deep well water. 



All three river waters are affected by floods and are, as 

 raw materials, of considerably different quality as regards 

 organic purity (see diagram No. 2). From these raw 

 materials by far the largest volume of the Metropolitan 

 Water Supply is derived, and the chemical or organic 

 purity of the water sent out to consumers stands in direct 

 relation to the organic purity of the raw material used, as 



