Water - The good news is we can do it

COWF:

Most of the cost-saving levers on the left of the cost curve for China are industrial efficiency measures. These have the potential to close a quarter of the gap and result in net savings of some $24 billion. They are distributed among the thermal power, wastewater reuse, pulp and paper, textile, and steel industries. Their savings potential derives from significant savings in energy and other operational expenditures, translating into overall productivity gains. The net capital expenditure to close the remainder of the gap amounts to $8 billion, or less than 0.06 percent of projected 2030 GDP.

...

(Sao Paulo) - Industries can generate significant financial benefit from reducing their water use via levers such as spring-valve installation and sensitivity sensors. Utility leakage reduction can save nearly 300 million m3. Wastewater reuse for gray-water purposes (such as industrial processes and public works uses) offers roughly 80 million m3 in new water.
…
Most solutions imply cross-sectoral trade-offs. South Africa has a balanced solution with cost-effective measures available across supply (which can close 50 percent of the country’s projected supply-demand gap to 2030), agricultural efficiency and productivity improvements (30 percent), and industrial and domestic levers (20 percent). Seven river sub-basins are almost entirely dependent on agricultural improvements, while the economic centers of Johannesburg and Cape Town are dominated by industrial and domestic solutions. Almost 50 percent of the levers involve significant savings of input costs, effectively making half of the solution “costnegative”. In the case of industrial levers (such as paste-thickening and water-recycling in mining, and dry-cooling, and pulverized beds in power), up to $418 million in annual savings can be captured from the pursuit of efficiency.

...

In India and China, for example, almost 75 percent of the gap could be closed with measures offering payback time of 3 years or less. São Paulo state, on the other hand, relies heavily on supply and efficiency measures that are not yet sufficiently attractive to adopters—86 percent have payback times above 5 years.
…
In India, where agriculture plays the most important role in the least-cost solution, aggregate agricultural income could increase by $83 billion by 2030 from operational savings and increased revenues, if the full potential of agricultural measures is mobilized.