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. This installation provided filtered water for every resident of the area, and the network design was widely copied throughout the United Kingdom in the ensuing decades.
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. Clean water was now abstracted from the natural channel which had been by-passed by the Hackney Cut, to a new reservoir at Old Ford. In 1830 the company gained a lease on the existing reservoir at Clapton.
- East London Waterworks Company, Brief history during the Snow era, 1813 – 1858 (UCLA Epidemiology), accessed August 28, 2016.