How did now higher-income countries make the transition in their urban water and sanitation services? How long did it take them? And what does that transition look like relative to economic wealth? That wealth being a proxy, perhaps, for societal willingness to pay for expanding and enhancing services ... eventually to all .....
The graph below shows the improvements in water and sanitation for a 'secondary city' in England (actually its 'second city' by some accounts) relative to the growth in GDP per person (2017 prices) over the two hundred year period - with a smoothed line for that economic growth, the actual line showing in faint print.
Intriguing to note that water meters were claimed to have been invented in the city at the start of the timeline .... only now moving to domestic metering for the majority ....
And to try and make sense of that development, the second version of the graph includes present GDP per person for Low, Lower Middle and Upper Middle-Income Countries as blocks, also showing the present average growth rates in GDP per person for Low and Lower Middle-Income Countries (starting from the present average GDP per person for those blocks - World Bank figures). Then adding the 'actual' growth rate required for Lower Middle-Income Countries if they were to achieve the SDGs over the timeline now available based on an equivalent societal demand. This is not to say that achieving the SDGs is not possible - but it is suggesting that it may well not be affordable (societal willingness to pay'?) without substantial 'transfers' from international donors. England only invested in improved watsan as and when society felt the need, either through cholera outbreaks in the mid 19th Century or through demand for improved living conditions and then environmental conditions in the 20th Century. And at the rate that the 'rich' were prepared/felt rich enough to support/cross-subsidise that improvement.
How much are we prepared to support 'global society' in achieving an accelerated transition?
To complement these graphs, included below is a graph detailing the investment levels in the England and Wales water industry over the past one hundred years (2014 prices, I will update this to 2017 and updated USD$ equivalence once the proposed Capex for 2020 to 2025 has been published. The black 'PWLB' line refers to the government's Public Works Loans Board which gave low interest cost loans for nearly one hundred years (stopping a short while before privatisation in 1989, perhaps deliberately to make the case for private investment? I don't know. And finally, a graph showing the percentage of GDP the water sector has been investing in England and Wales though this percentage should be a little higher to account for the investment in Scotland and Northern Ireland - I will update the figure accordingly when I update the Capex information.