The City Dehumidified

I'm in London, watching snowflakes fall amidst early morning rain flurries, reading David Grann's new book The Lost City of Z, and getting ready for the Barbican event tomorrow night.
But there's an article in the Guardian today about the WaterMill, which "uses the electricity of about three light bulbs to condense moisture from the air and purify it into clean drinking water." The company, Element Four, imagines a future for their product involving everything from irrigation and personal thirst to peacekeeping and disaster relief. Perhaps it might even require an update to the atlas of hidden water – where the water supply is "hidden" in the sky itself.

[Image: A diagram of the WaterMill at work].

As the company describes it:

The system draws in moist, outside air through an air filter. The moist air passes over a cooling element, condensing the moist air into water droplets. This water is then collected, passed through a specialized carbon filter and is then exposed to an ultraviolet sterilizer, eliminating bacteria.

Further:

The WaterMill is installed unobtrusively on the outside of your home, using outside air, so it won't dry out the air you breathe in your home. And don't worry if your outdoor air is less than pristine – even if you live in a crowded city, the Watermill's filtration system ensures your drinking water will be clean and free of toxins and bacteria – more pure than tap water or even spring water.

You're basically drinking water from a dehumidifier, then.
According to the Guardian, the obvious – if extremely uninteresting – next question is: "are you crazy?" But it would seem that the next question might actually be one of large-scale climate-engineering and the future of urban design.
In other words, would it be possible to re-engineer a city's weather patterns through the judicious and geographically strategic deployment of WaterMills? What might happen if this were to occur accidentally, over time, and according to no particular plan?
Over the years, say, tens of thousands – even millions – of these machines are installed in a humid city like New York, Tokyo, or London, achieving imperceptibly slow local climate modification. The city goes into a drought, with very little rainfall as humidity disappears – and it's all because of a certain line of products that have been installed, gradually, home by home, over the course of a decade.
Sucking hundreds of thousands of liters of water out of the air everyday, and re-directing that water into the sewage system through the metabolic processes of human bodies, these machines inadvertently re-engineer the local climate.
I remember walking to a restaurant through almost unbelievable summer humidity, thinking that massive, solar-powered air-conditioning units installed atop Manhattan skyscrapers could flood the surrounding streets with downward winds of cooled air to avoid uncomfortable nights – but industrial-sized WaterMills might accomplish the same thing, sitting up there in the heights of the marvelous, stealing water from the sky. Anti-clouds. Black engines atop roofs prevent rainfall. Whole summer storms could be stopped before they form. City-wide, temperatures drop and the humidity falters.
The resulting fresh water is then sold to Spain.
So if designer climates are the future of urban design, something explored in the forthcoming BLDGBLOG Book, then perhaps the widespread use of WaterMill technology might be an interesting way to start. Convince enough people in one large building, say, or even one borough, to install a home WaterMill... and see if the local climate begins to change.