 In 1825, the ponds of the Chelsea Waterwork Company were used as the basis of the Grosvenor Canal which was opened to traffic that year.By this time there were complaints about the quality of the water that the company was drawing from the River Thames, and in 1829, under engineer James Simpson the Chelsea Waterworks Company became the first in the country to install a slow sand filtration system to purify the water.In 1829, the East London Waterworks Company moved their source of water further up river to Lea Bridge as a result of pollution caused by population growth.