Water supply is likely to be the next big ecological crisis in the U.S., and this crisis likely will come as a result of drought and lack of funds for infrastructure upgrades to provide new sources of supply for a population that continues to grow. One response to America’s growing water shortage might be an increased business and government focus on water conservation, water efficiency technologies, and on-site water treatment and reuse, both in homes and buildings. This situation could produce unprecedented opportunities for contractors, technology suppliers, and engineering consultants. What’s more, the continued growth of LEED, especially LEED for Existing Buildings: Operations & Maintenance (LEED-EBOM), will put extra emphasis on water efficiency for building owners and designers looking for green solutions.
My report for the Mechanical Contractors Education and Research Foundation, “Water-Efficiency Technologies for Mechanical Contractors: New Business Opportunities,” reviews a range of options available to building practitioners in addressing water use, ranging from water efficiency audits to rainwater harvesting, graywater reuse, high-efficiency fixtures, and cooling tower water conservation. Practitioners looking for solutions may want to consider some of the following areas.
Impending code changes from both the International Association of Plumbing and Mechanical Officials (IAPMO) and the International Code Council (ICC) will facilitate adoption of local codes permitting both rainwater and graywater reuse. Code issues may make your eyes glaze over, but they are critical for opening up possibilities for reclaimed water. The IAPMO’s Green Plumbing and Mechanical Code Supplement to its 2009 Uniform Plumbing & Mechanical Codes will be released in February 2010 and will include greatly enhanced requirements for water efficiency including graywater recycling and high-efficiency plumbing fixtures.
Fixture renovations can be made at any time using a new generation of low-flow toilets, sinks, urinals, and other appliances. So-called High-Efficiency Toilets (HETs) use 20 percent less water per flush, which is 1.28 gallons, and are now required for all new product sales in California and Texas. The Environmental Protection Agency’s (EPA) WaterSense program already certifies low-flow toilets, bathroom sinks, and urinals for commercial buildings. In the pipeline are low-flow showerheads, pre-rinse spray valves for commercial kitchens, and landscape irrigation controllers. The EPA has announced a WaterSense Home specification for builders that will complement the existing Energy Star program for new homes. Over time, WaterSense Homes could reduce water consumption by 20 percent, depending on the efficiency of the devices installed.
Some experts are concerned that reduced water flow might cause drain line problems, as there would be less water available to flush solids and paper, so the plumbing industry has commissioned a research project to study this issue.
Rainwater and Graywater Harvesting
Rainwater harvesting and graywater reuse are good technologies for new buildings and major renovations, since they both require dual piping systems to collect, treat, and reuse water inside the building, as well as space for possible water storage. Typically, rainwater storage systems are integrated with a building’s fire-storage water tank. The storage tank often is sized to hold 50 percent or more of the water from a site’s annual rainfall as creating a tank big enough to capture 100 percent of the annual rainfall usually doesn’t pay since much of a site’s annual rain often falls during a few big showers or storms. The harvested and treated rainwater can be used for toilet flushing, site irrigation, or to generate makeup water to compensate for loss of water to evaporation or leakage in a cooling tower.
Installing these systems in existing buildings is more costly and technically difficult. However, rainwater harvesting is gaining popularity for use in conjunction with existing buildings because it’s feasible to implement an on-site treatment and reuse system to generate cooling tower makeup water or for use in landscaping, two applications that don’t require installing new piping in the existing building. There also are opportunities in existing buildings for graywater reuse, a technology that involves both mechanical and landscape contractors, since most graywater captured and treated will be used on-site for landscaping.
Nonconventional technologies for on-site blackwater treatment and reuse are slowly gaining support, but probably will take another five years to gain any form of popularity. At present, their use is limited to new construction projects with educational objectives and those seeking high levels of LEED certification.
LEED-EBOM and the New Water-Efficiency Technologies
All LEED rating systems now require a 20 percent reduction in water use as a prerequisite for certification. In 2009, the fastest growing LEED system was LEED-EBOM, which added about 1,700 registered projects totaling more than 400 million square feet through the end of September alone. Retrofits are the next huge water conservation opportunity, and LEED-EBOM certification is an important driver of both energy and water retrofits.
LEED-EBOM’s water efficiency prerequisite mandates that a project reduce water use 20 percent below the LEED baseline. The baseline assumes that all building fixtures meet the 2006 Uniform Plumbing Code or the 2006 International Plumbing Code. The baseline is raised 20 percent from the code limits for buildings completed in 1993 or later and 60 percent for buildings constructed prior to 1993. For example, let’s consider the case of a building completed in 1990 with 100 water closets flushing at 3.5 gallons per flush (gpf). The current code is 1.6 gpf, so the baseline would be 2.56 gpf (1.6 gpf plus the 60 percent baseline adjustment). To meet the prerequisite, you’d have to reduce water use by about 27 percent, which means you’d have to change out roughly 50 percent of the toilets to fixtures that meet the new codes (94 gallons required savings divided by 1.9 gallons savings per fixture). At today’s water rates in most cities, a building owner would make money doing this, since future water savings would more than pay for the costs of the upgrade.
LEED-EBOM awards up to 14 points for water efficiency attainments and a project may attain additional bonus points for exemplary performance or for meeting regionally significant water-use reduction targets. However, water conservation is doubly important when you consider that the process of capturing, storing, transporting, distributing, and treating water consumes significant amounts of electrical power.
I recommend that contractors, engineers, manufacturers, and system designers have a single point of responsibility inside their companies for tracking the progress of water-related technologies and the associated opportunities. For example, there are immediate business opportunities in water audits, as well as water-efficient fixture retrofits. Further, contractors, engineers, manufacturers, and designers should gain experience with cost-effective retrofit opportunities now while on-site water efficiency and recycling is still in a developmental stage.
Jerry Yudelson is principal at Yudelson Associates in Tucson, Ariz., and the author of Dry Run: Preventing the Next Urban Water Crisis. To view his full report on water efficiency technologies and the business opportunities associated with them, visit greenbuildconsult.com.