Work included replacing the uninsulated concrete exterior with a high performance curtain wall and installing a large roof canopy containing PV panels and rainwater collection system for toilet flushing and irrigation. (architecture2030.org)
Given these benefits, some states, including even drought - prone Texas, subsidize residential rainwater collection systems. (scientificamerican.com)
It has its own rainwater collection system that feeds into the indoor plumbing, in addition to the 120 - watt solar panel system to provide electricity. (treehugger.com)