California’s years-long drought conditions and this winter’s unpredictable, underperforming El Niño rainy season have put water issues at the forefront of the state’s public attention. Just as interest in clean energy and energy conservation spurred an explosion of energy-saving technologies and regulations in California years ago, the way we think about water conservation and water reuse in our state may now be poised for a major overhaul. Directives from the state of California, the initiatives of individual project owners, and the efforts every stakeholder in between are contributing to a revolution in the ways we use, save, and treat our water.
Here in southern California, for example, local regulations are opening the door for innovative water saving strategies. As part of the Beverly Hills Revitalization Plan, the currently under-construction Waldorf Astoria Beverly Hills will be required to irrigate all landscaping with nonpotable water. To this end, the project includes an Aquacell greywater system that collects and treats shower, tub, and lavatory water from a swath of hotel rooms to be used for irrigation. In San Francisco, beginning last November projects over 250,000 square feet are required to meet both irrigation and toilet flushing demand to the greatest extent possible utilizing recycled water produced onsite, including recaptured greywater and rainwater. This regulation, which prescribes the ends but not the means, forces each project to consider strategies to minimize water demand and maximize recycled water supply that are unique to the intended use, building design, and inherent hydrology of each site.
Due to growing interest and concern for the drought in California, more and more project owners are looking seriously at water conservation strategies without direct mandates from local regulators. For example, A/G is working with a large restaurant group dedicated to tackling water issues at a new Southern California location. The project is early in design, so many water conservation and water reuse strategies are still being carefully considered. The most plentiful potential supply of water for capture and reuse onsite is kitchen process water – this is a major challenge, since under local regulations kitchen water is considered blackwater, which requires additional treatment and currently can only be used for subsurface irrigation. For the project this presents a tension between supply and demand. Greywater can be collected, but only in relatively small amounts that cannot measure up to high demand uses such as toilet flushing. Blackwater can be collected and reused, but it is costly to treat and the supply far outstrips the demand for subsurface irrigation alone. The project team will work together with local regulators and third-party water reuse technology companies to find solutions that maximizes water savings while satisfying all public health and safety regulations. As one of the first projects of its kind to consider onsite water reuse in Los Angeles, this project will be paving the way for future commercial kitchens to utilize these technologies.
For projects without commercial kitchens, other types of process water can be a potential source of greywater supply as well as an often-overlooked area for water conserving technologies. By using technologies that increase the number of times water can be cycled through water-using building systems such as cooling towers, for example, projects can conserve water much more effectively than through the use of low-flow plumbing fixtures alone. For further savings, projects can look for ways to treat and reuse the process water after its final cycle, whether for toilet flushing, irrigation, or other uses.
Even as more and more municipalities and project owners are experimenting with innovative, technology-based solutions for water conservation and water reuse, California isn’t wasting any time in moving forward with common sense, low-tech water conservation solutions. Starting this year, California’s already stringent maximum flow rates for basic water fixtures are being further slashed, and not just for new projects. Starting this year, the installation and sale of any new urinals with a flow rate greater than 0.125 gallons per flush will be prohibited – this aggressive standard matches the maximum flow rate already in place for the City of Los Angeles. The maximum flow rate for kitchen sinks is reduced to 1.8 gallons per minute and, perhaps most controversially, the maximum flow rate for residential lavatory faucets is reduced to 1.2 gallons per minute (http://drought.ca.gov/news/story-81.html). This last item alone is expected to save about 4.5 billion gallons of water, 16 million therms of natural gas, and 118 gigawatt hours of electricity in the first year the standard is in effect, though there is some discussion of delaying implementation of this measure until July 2016 due to limited availability of compliant fixtures on the market today. (http://www.energy.ca.gov/business_meetings/2015_packets/2015-08-12/Item_06/Item_6_Faucet_Staff_Paper.pdf).
California has come a long way in its regulation of water as a part of our built environment, from seeing water as a one-dimensional utility to a precious resource that interacts in complicated ways with with our infrastructure as well as our energy budget. Taking an even wider view of water, though, will be an important part of the next major step forward in thinking about water – large scale stormwater retention strategies to keep California’s reservoirs filled and infiltration and reclamation of California’s polluted aquifers to ensure a safe, clean, and plentiful water supply for generations of Californians to come.