The Colne Valley Water Company was a statutory water company, formed in 1873. For a hundred years its water supply was obtained from underground sources accessed by boreholes. Pressure on these resources led to the Three Valleys Scheme and the construction of nine miles of trunk main from the River Thames was completed in 1974. In 1994, Colne Valley merged with the other two companies in the Scheme, the Rickmansworth and Lee Valley Water companies, to form Three Valleys Water plc. That in turn was acquired by Veolia Water in 1987.