Hi, here you can find an example showing development of specific water consumption vs metering level in a small town of Leova, Republic of Moldova. It is clearly seen that a total specific consumption decreased as result of installation of water meters. https://ru.scribd.com/doc/254659363/Indicator-Report-Water-Supply-Leova-Moldova
You may also want to analyse additional indicators (e.g. collection ratio, etc.), so you can easily get these data from http://www.ib-net.org/ . This database contains quite comprehensive benchmarks from the developing countries. Good enough for a desktop analysis. Enjoy!