Zenith International chair Richard Hall today noted the launch of the water, which has apparently been sold since 2012.
It's clearly a major customer draw, if the Casa del Agua Facebook page is anything to go by! It's also quite a business model. Clearly you'd need somewhere relatively pollution free with a high rainfall.
I'm not saying anything about Mexico City pollution levels - they appear to be quite high - but the water is clearly a seasonal product. Beyond June-October there's relatively little rain.