I've been following IB-NET for several years. It's a World Bank project that collects data on water/wastewater charges (at a high cost of time and money) and they publishes that data in an easy-to-use and compare format that really helps researchers, policy people, water managers, and just normal people understand who prices are set, where they are unsustainable, and so on.
I recommend that you head over to IB-NET to check out your country -- and maybe even your city!
Here's Amsterdam (click to enlarge):
and here's Los Angeles:
Comment: It's curious that Amsterdam -- relatively speaking -- is more expensive to small users (15m3 is 41 liters/day) but cheaper for heavy users. That's probably because Amsterdam has plenty of water and a top-notch system. Are LA's prices "right"? If the water is on and safe, then yes. If there's a risk of shortage or network failure, then probably not. (Money helps, but good regulation and professional managers are what make a system work, long run.)