As the industry increased and other gas works were opened, so the problem increased. The effect on the water systems was soon apparent. Many sewers were old natural watercourses into which domestic effluent ran, and from there into the Thames. While the waste was domestic and on a small scale it was acceptable, but the rise of large-scale industries - like gas - caused immediate problems. The Thames became seriously polluted. By the early 1820s the river was unfit 'for culinary purposes' as eels and fish died.
This had an immediate and serious effect on the Thames fishing industry. In 1815 there were been many fishermen between Dartford and Richmond. They had expected to catch around 10,000 salmon in season and 50,000 smelts each year. Within five years of the gas industry opening only half of the smelts were left and the salmon had all gone. Dead fish were found which smelled strongly of gas: 'The residue of the gas works.. floats on the surface in patches like oil'. It is in this period that Thames fishing as a major industry collapsed.
In 1822 the City of London successfully prosecuted the Chartered Co. 'on account of the communication between the works in Peter Street and the river Thames'. Indicative of the mood of the early 1820s is a Parliamentary Bill 'to prevent washings of substances from making of gas being conveyed into rivers' - presented, but never passed, in 1822.
The history of London's water/sewage system has been covered in a number of works, some written for a popular audience. These have often appeared as either engineering or local government problems. Both have concentrated on the solutions rather than the continuing problem. Such histories have tended to highlight successive cholera epidemics and the achievements of the Metropolitan Board of Works in the 1850s. Public discussion on London's water supply and disposal system had begun long before this and was gathering momentum as time went on.
A number of water supply companies had been set up in London in the early years of the century. Their establishment in many ways parallels that of the gas industry. Many of the same factors which affected the rise of the early gas industry in London influenced the water supply industry. Legislative, financial and technical developments are all important and sometimes complementary. The first cholera epidemic of 1827 provided a focus for continuing disquiet on provision and disposal of water. Initially attention was drawn to the sources from which water was drawn for distribution to the public. A Royal Commission into drinking water was set up. To them gas industry effluent was just one of many concerns.
Much later in the century these concerns were to come together with the engineering solutions of the Metropolitan Board of Works. Before this could take place, the tools for the analysis of water pollutants were developed. The story of Dr. Snow and the Broad Street pump is well known. However these two famous episodes in the history of the London cholera outbreaks and water supply are usually told today with the benefit of hindsight. In 1827 the problems were not so clear. Cholera was one problem - for which neither the cause nor the solution was known. Increasing pollution of water supply was another, different, problem - but one that caused disquiet and in which the new gas industry was seen to be a major player.