In a bit of coast-envy, suddenly Chicago is at the forefront of an environmental movement. As Californians move to catch up to this growing phenomenon, even they acknowledge Chicago encourages living roofs on most new public buildings, and is nudging private developers to do the same. It started on the top of City Hall, after a visit to Germany by Mayor Daley in 1997. Green roofs can reduce heat needs inside the structure and capture rainfall before it gushes into larger drainage systems, keeping as much as 70 percent and filtering the rest. In addition, the green rooftop is estimated to save $10,000 per year in energy costs for the building.