[jeza]

Interesting topic. The Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia has been looking into the usage of aquifers for water storage in urban areas for some time now (the most recent project was Managed aquifer recharge and storm water http://www.csiro.au/en/Research/LWF/Areas/Resilient-cities/U... from 2010 to 2014, though I remember reading reports about some research around 15 years ago).

I think it is particularly interesting that their research is focused on urban areas, where all the concrete and bitumen results in huge runoff. This creates risk of flash flooding, wastes a useful resource and even causes problems for marine life. So if it can be stored underground in natural aquifers and utilised locally that'd be quite an improvement. Apparently the cost of treating storm water for drinking is similar to treatment of water from reservoirs. No doubt there'd be a pretty big saving infrastructure needed for distributing water over long distances as well.