Cancun is a city with close to one million inhabitants looking like a smaller town, and a short distance from the center is the 22.5 km long hotel zone which is located on a peninsula around a huge lagoon. The hotel zone is very posh.

The water used in the hotels (as well as the town) is groundwater. 

What are the hotels in Cancun doing with their water after use and what is done in Miami Beach? Who has developed smart concepts and who hasn't and what can motivate the hotel chain operators to apply good concepts?