Case Study

Tah.Mah.Lah. Residence Tah.Mah.Lah. – Welcome to the Greenest Home in America

Portola Valley, California, USA

The Challenge

To design a residential home that would be 100 percent sustainable for generations to come and seamlessly integrate into its ecosystem, producing more energy than it consumes, restoring habitat, saving and repurposing water and reusing waste.

The Design Solution

Built with reclaimed wood, glass, metal and stone and fully solar-powered, the 5,600 square-foot Tah.Mah.Lah. eliminated its own and its occupants’ total carbon footprint, including transportation. All water used at the site is recycled or repurposed and a high-efficiency irrigation system uses harvested rainwater and treated black/grey water with the help of a 50,000-gallon underground cistern. The design solution centered on all four areas of sustainable and regenerative building: energy, materials, water and habitat, delivered by a team of more than four dozen project consultants and artists, wastewater system engineers, energy specialists and wildlife biologists, collaborating in a fully integrated design process incorporating the owners’ lifestyle and green goals.

The Design Impact

Tah.Mah.Lah. achieved USGBC LEED for Homes Platinum certification; with the homes’ innovation credits, it is the greenest custom home in the United States. It’s also a demonstration project, serving as an inspiration and educational place to share knowledge and build green, helping create a market for green ideas, goods, services and jobs. Since July 2011, Tah.Mah.Lah. has hosted numerous groups and tours – Stanford University students, USGBC Greenbuild Conference tours, and Bay Area Peninsula mayors who discussed ways to create sustainable cities.

Project Features

  • Net-zero energy including transportation
  • Fossil fuel free
  • Nearly all — 99 percent — construction materials recycled/repurposed
  • Native landscaping and habitat restoration (all California-native plants, except for an organic food garden)
  • Solar-heated pool


  • 2014 National Wildlife Federation, Certified Wildlife Habitat
  • 2014 Interior Design Magazine, Best of Year Award, Green Category
  • 2012 National Association of Home Builders
  • 2012 Green Builder Magazine, Green Home of the Year
  • 2012 Sustainable San Mateo County, Residential Award of Excellence