San Francisco Skyscrapers: Leading the Charge in Water Conservation.June 8, 2015
California is currently in the midst of one of the most severe droughts on record, and avoiding a further crisis will doubt require a great deal of collective and individual sacrifice. The San Francisco area is the unquestionable state leader in the water conservation effort. SF residents are some of the lightest sippers in California, using only 49 gallons of water per day as compared with the state average of 100 gallons. Even more impressively: even though the population of the city has exploded in recent times, total customer water use has decreased over that same time period. San Franciscans take water conservation seriously, and it shows.
But San Francisco’s residents aren’t the only ones who are watching every drop — the towering buildings that make up the City’s famous skyline are also tightening their belts in ways that range from seemingly mundane to brilliantly innovative.
The Transamerica Pyramid is SF’s most distinctive and recognizable skyscraper, and it’s also a quintessential example of the way that smart design can cut a structure’s environmental footprint. In 2011, the building received a Platinum LEED rating (LEED stands for Leadership in Energy and Environmental Design) from the U.S. Green Building Council, a milestone upgrade from the Gold rating the building received just two years prior. Platinum LEED ratings are given only to those buildings that combine continual structural and engineering improvements with a powerful leadership element that drives the occupants to be conscientious of how their actions affect the environment. The Pyramid’s initial Gold rating and the subsequent upgrade came on the heels of decades of work from all involved parties, but the environmental protection payoffs are well worth the effort.
Water conservation at the skyscraper level usually focuses on two areas: plumbing and fixture retrofits and water reclamation and recycling. Changes as simple as adding aerators to bathroom faucets and switching to Ultra-Low-Flow Toilets can result in huge improvements in water efficiency (20%, in the case of retrofits performed on the Transamerica Pyramid) without negatively affecting the lives of a building’s occupants. Sweeping changes to a skyscraper’s pre-existing plumbing might seem like an unfathomable task. But, improvements to the Transamerica Pyramid, as well as other notable LEED Platinum structures like Taipei 101, show that meaningful increases in water efficiency are within reach.
Aside from controlling occupant water use through plumbing and fixture modification as the Transamerica Pyramid does, high-rises can also find innovative ways to capture and re-use what’s already been through the pipes. Because access to potable, high-quality water has never historically been a problem, industrialized societies have simply used the high-quality water for everything, even when lower-quality, non-potable water will do.
There are two accessible sources of lower-quality water that could be employed by SF skyscrapers: rainwater, “blackwater” (used water that has been in contact with human waste) and “greywater” (lightly-used water that has not). Processing these sources on-site to be fit for human consumption would be a time- and energy-intensive process, but the standards for re-use in toilets, laundry, and cooling systems are much lower. While installation of the right water-reclamation systems would by no means be free of cost, almost half of all office building water use requires only a non-potable source. Accessing and utilizing these non-potable sources would represent a huge step towards meaningful water conservation at the office building level.
Our state is at a crossroads with respect to its response to this historic drought, but San Francisco has been a leader in conservation efforts across the board. Still, it’s crucial that we continue to look for further solutions and innovations that will change how we use water in both our homes and our high-rises.