The Green Supplement is not a "greener" version of the Uniform Codes, but rather a separate document establishing requirements for green building and water efficiency applicable to plumbing and mechanical systems. The green supplement covers: Water efficiency and conservation including: High efficiency fixtures, fixture fittings, and appliances High efficiency plumbing fittings, fixtures and appliances Water softening equipment Cooling towers and Evaporative cooler Alternate water Source Usage, including gray water, rainwater, and recycled water Water heating system, including equipment efficiency, insulation, recirculation, design and system controls Energy efficiency for HVAC systems based on ASHRAE 90.1 and 90.2 Enhanced environmental quality for buildings based on ASHRAE 62.1 and 62.2