While some have suggested taking abandoned or foreclosed McMansions and putting them to constructive uses (see an example here and here), there are also less constructive uses:

Manteca Police filled a huge dumpster to the brim with some $2 million worth of marijuana plants after executing a search warrant at a home midway between Woodward Park and South Main Street

Sgt. Chris Mraz, heading up the four-member Street Crimes Unit (SCU), said the search of the 4,000-square-foot, two-story rental home in the 1800 block of Arlington Court contained the largest marijuana grow he has ever seen within the city of Manteca.

Elaborate marijuana growing operations have been found in other Manteca neighborhoods in the so-called McMansions due to their massive square footage. The last such large operation was found off Pestana Avenue near Joshua Cowell School…

The in-house nursery was highly sophisticated with growing operations underway in every room of the house, Mraz said, except for one bedroom that was used by one of the two men in a caretaker role. He noted that the plants found in the grow operation went from seedlings to fully mature plants. The Street Crimes Unit lead detective said the grow made the one found last year in a vacant building in the Manteca Industrial Park look insignificant in comparison.

This sounds like a plot of a typical movie depicting the suburbs: who knows what your suburban neighbors are really doing next door.

Just how many McMansions are home to such plots?

At the same time, the amount of water and electricity needed for this operation would fit the stereotype that McMansions are not green at all.