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1. Water Performance: Getting the Most from Every Drop

1. Water Performance: Getting the Most from Every Drop

August 11, 2010
This article first appeared in the 200911 issue of BD+C.

Since 2003, Building Design+Construction has produced a series of annual reports on the green building movement.¹ Our first two White Papers covered the early days of green building. In subsequent reports, we took on life cycle assessment of green building products (2005); analyzed the bottom line of green buildings (2006); and conducted groundbreaking studies of owner and user perceptions of green buildings (2007). Last year, we tackled climate change in an effort to help our audience of AEC professionals, building owners, and real estate developers understand the impact of global warming on their businesses.

Together, these White Papers encompass more than 225,000 words—enough for a decent-size book—and provide arguably the most sustained, objective analysis of the green building movement available to the AEC community. Four have been finalists for the Jesse H. Neal Award (called the “Pulitzer Prize of the Business Press”); two have won that award, along with national awards from the Construction Writers Association and the American Society of Business Publication Editors.

Now, in our seventh White Paper, we turn to water. Why water?

The availability of water is becoming an increasingly serious public issue. A 2003 survey by the General Accounting Office found that water managers in 36 states foresaw water shortages hitting their states to some extent over the next 10-year period under merely “average water conditions” (Figure 1.1). Colorado and South Carolina said their states would be entirely under drought; 16 states said one or more regions would be affected, while another 18 states saw localized water shortages.²

Two water-stressed states, California and New Mexico, did not complete the survey (along with Michigan). Georgia, which experienced a crippling drought in 2007, said in 2003 it would only experience “localized” water shortages.

Water managers in 11 states told the GAO that their states were likely to experience water shortages “under drought conditions” in the following decade; 29 states said water shortages would be regional, and another six said it would be localized. Again, California and New Mexico did not participate.

On top of this, the U.S. will be adding another 100 million to its population over the next three decades, adding further to water stress.

Defining water performance. It is important to draw a distinction between water efficiency and water conservation, according to John Watson, water efficiency director for Sloan Valve Co. (a sponsor of this report). Water efficiency is driven by technology—how well a plumbing device such as a toilet or showerhead can operate effectively, using the least amount of water. Water conservation refers to the actual consumption of water by the end user. “You have the efficiency component and the conservation part of the formula. Together, they yield water performance”—a measure of how well the technology works and how well it meets the needs of the end user, says Watson.

Although power plants withdraw large amounts of water, only a small percentage is evaporated; as a result, power plants consume only about 3% of the water in the U.S. Agricultural irrigation accounts for the great-est amount of actual water consumption, 82%

For example, Watson points to plumbing industry research which showed that 95% of consumers were satisfied with a flow rate of 0.8 gallons per minute for high-efficiency lavatory faucets. For high-efficiency showerheads, the industry first modeled an optimal system, then built an apparatus to test the “ideal” model in the real world. “We actually proved that the data we came up with mathematically”—a flow rate of 2.0 gpm—“was a good shower” in most people’s view, says Watson.

Kate McMordie, of the U.S. Energy Department’s Pacific Northwest National Lab, frames “performance” another way. “It’s not about everyone taking shorter showers” to save water, she says. “It’s doing the same function with less water”—with no loss of end-user satisfaction.

How water is used. Buildings account for somewhere around 12% of water use in the U.S., according to the U.S. Geological Survey (or 14%, if you use the U.S. Green Building Council’s figure). The preponderance of the water that is actually consumed in the U.S.—82%—is used for irrigation (Chart 1.1). About two-thirds of water use in urban areas goes to homes, apartment buildings, and condominiums (Chart 1.2). And nearly two-thirds of the water for single-family homes winds up on the lawn, or is lost to leaks (Chart 1.3).

In 2003 water managers in 36 states said they anticipated shortages in local areas, regions of their states, or statewide in the next 10 years under “average water conditions.” Forty-six of 47 water managers said at least portions of their states were likely to experience water shortages “under drought conditions” in the next 10 years; 11 said such conditions would impact their entire state. California, New Mexico, and Michigan did not respond to the GAO survey.

This raises the question of how much water homeowners and building occupants can actually save.

“One of the real disconnects we have is that you 'know’ what you 'see,’ says Rob Zimmerman, a senior staff engineer for water conservation initiatives at Kohler Co. (a sponsor of this report). “People think the toilet wastes water, or the shower wastes water. But only about 4-5% of water use in U.S. goes through plumbing fixtures. When we talk about water shortages, there’s only so much we can do on the plumbing side. If people think we’re going to solve this problem with low-flow showerheads and faucets, that’s not going to happen.”

This is not to say that we shouldn’t seek what Zimmerman calls “definite and attainable goals”: an average 100 to 250 gallons per capita per day (GPCD) for single-family homes, about 55-70 GPCD for indoor use—possibly as low as 40 GPCD for indoor use in new green homes. Bill Gauley, a water engineering expert with Veritec Consulting, Mississauga, Ont., thinks 32 GPCD is feasible.

Residential uses account for nearly two-thirds of actual water consumption in the urban portions of the U.S. In the late 1990s, the AWWA Research Foundation commissioned Aquacraft Inc. to study the end uses of water in 100 single-family homes (statistically selected to be representative of all single-family homes) in 12 cities and water districts.* Indoor use, not counting leaks, accounted for about 35% of the total. The bulk of single-family water use occurred outdoors.

But indoor plumbing may not be the real culprit. As we shall see (Chapter 4), landscape irrigation uses a lot more water than is used inside buildings or homes.³ “Using potable water for irrigation is a sin,” says Toto USA’s Gunnar Baldwin, a charter board member of the Alliance for Water Efficiency. “It’s totally unnecessary and should be banned completely.”

In commercial buildings, cooling towers can account for a major chunk of water use, especially in hot, dry climates, says Texas-based water consultant H.W. (Bill) Hoffman. “In a typical office building in downtown Austin, cooling tower use typically would be 30-50% of total water use,” he says. On a hot, dry day, an office building with 800-1,000 tons of A/C equipment can use 20,000-30,000 gallons a day, “even if the system is operating efficiently.”

Hospitality (restaurants and lodging), office buildings, hospitals, and schools and university buildings represent good opportunities for water performance improvements. These • gures are based on the EPA’s “Study of Potential Water Ef• ciency Improvements in Commercial Businesses (1997) and, according to the EPA, “represent the largest national data sample to date, and are consistent with other available studies regarding subsector water usage” in commercial and institutional buildings..

The true cost of water. In the U.S., water, like gasoline, is cheap. It is estimated that water used for agricultural irrigation is priced at only one-sixth of its true value. According to Jeff Kishel, PE, SVP and leader of A/E firm Stantec’s environment business, agricultural users may pay about $10 an acre-foot for water, while residential users might pay hundreds of dollars for the same amount, depending on location.

Becoming more efficient also drives up the unit cost of water. “Los Angeles is using the same amount of water it used 20 or 30 years ago, but the cost per gallon has gone up, because your fixed costs are virtually the same,” says Kishel.

In fact, water in the U.S. is so cheap that it makes it difficult to pay for much-needed improvements to the system. “The true cost of delivering clean water continues to creep slowly upwards, as does the average price of water, but not at the kind of rates that would seem to be required if we are going to upgrade and truly maintain our infrastructure on a sustainable basis,” note the editors of Environmental Business Journal in their recent WaterView 2009 Report. “It seems clear that we still don’t really recognize the true value of water—nor do we have to currently pay a price for water anywhere near what it is really worth to us.”4

Hidden costs of water. One of the less well-understood aspects of water is its energy cost. In most parts of the country, however, water has to be pumped to its point of use, and that takes energy, usually in the form of electricity or natural gas.

Water processing and distribution, coupled with sewage treatment, consumes about 4% of electricity in the U.S., according to the Electric Power Research Institute (EPRI), Menlo Park, Calif.5 A 2009 analysis by River Network, Portland, Ore., estimated U.S. water-related energy use—including heating water for homes and businesses—at 521 million MWh a year—equivalent to 13% of the nation’s electricity consumption.6 In California, water transport and treatment accounts for 19% of electricity used in the state. For many older municipal water systems, supplying fresh water to buildings and homes can account for 80% of the energy used by local water utilities, according to the Alliance for Water Efficiency

Crumbling infrastructure. The U.S. has about 700,000 miles of water and sewer pipe, of which an estimated 72,000 miles are 80 years of age or older. “The stuff’s falling apart,” says Stantec’s Jeff Kishel. “A lot of it is owned by public agencies and they tend to leave it in the ground until it falls apart. A lot of this infrastructure is nearing or at or even beyond its useful life.”

Greg Kail, public affairs director for the American Water Works Association, whose 60,000 members represent the nation’s water utilities, says what the AWWA calls “non-revenue water” comes in part from such things as water lost due to fire hydrants being flushed. As for leaks, says Kail, “We’ve gotten away from what an average percent would be, because of the various ways it’s measured” by the nation’s 54,000 community water systems. A 1996 estimate said that a 10% loss would be “a good level,” says Kail, but experts say it could be as much as 20-30% in older cities of the Northeast and Midwest.7

The nation’s larger water utilities are spending billions on infrastructure improvements—$46 billion for water (in 2004), $36.4 billion for sewers (2005).8 According to Jennifer Hoffner, of Portland, Ore.-based American Rivers, Atlanta has cut its leaks from 20% to about 14-15%. Chicago has made significant strides in relining and repairing miles and miles of its water pipes.

The AWWA says that an additional $250 billion spread over the next couple of decades is needed; the 2003 EPA Drinking Water Needs Survey put the cost at $276.8 billion over 20 years. But that kind of investment is unlikely to happen. Of the $787 billion in the economic stimulus, for example, only about $2 billion is set aside for drinking water improvements and about $4 billion for wastewater—“a drop in the bucket,” according to Kail.

In the meantime, billions of gallons of fresh water will be lost en route to homes or buildings, building owners will be charged for sewer services for wastewater that never reached the treatment plant, huge amounts of energy will be consumed, and untold tons of greenhouse gases will be generated.

'Unintended consequences.’When it comes to water performance, sometimes doing the right thing creates “unintended consequences,” to use the phrase du jour. Manufacturers are getting so good at making toilets efficient that we may be in danger of not having enough wastewater to flush the sewer lines properly—the so-called “drain line transport problem.”

In the U.S., five organizations—the Alliance for Water Efficiency (AWE), the Plumbing Manufacturers Institute (PMI), the International Association of Plumbing and Mechanical Officials (IAPMO), the International Code Council (ICC), and the Plumbing-Heating-Cooling Contractors Association (PHCC)—have formed the Plumbing Efficiency Research Coalition. PERC’s first initiative: a research study on the drain line carry problem, which will seek to determine the minimum amount of water necessary to safely flush drain lines.

Another “unintended consequence” is what Gary Nuss, managing principal for water resources at Jacobs, calls “regulatory drought.” This occurs when protecting the environment trumps human need for water. This past July, a U.S. District Court judge ruled against the U.S. Army Corps of Engineers in favor of Florida, which said it was entitled to water from federally controlled Lake Lanier, Atlanta’s main reservoir, to maintain marine life in the Chattahoochee River on its side of the Georgia-Florida state line.


“One thing that’s quickly gaining momentum is water reuse,” says Sloan Valve’s John Watson. “This is the next big thing.”

Water reuse involves both graywater and rainwater. In the case of graywater, why not collect the wastewater from sinks, clothes washers, and showers, give it a moderate level of filtering and disinfecting, and use it to flush toilets in a house or building? Why not give this valuable resource a second life, so to speak? It may seem logical, but plumbing, building, and health regulations in many jurisdictions prohibit this practice as a potential danger to the health of building occupants.

Likewise, it would seem to make sense to use roof runoff for other useful purposes. “We’re using fresh domestic drinking water to irrigate grass and replenish cooling towers,” says Rick Reinders, president of Watertronics, Hartland, Wis., a manufacturer of rainwater harvesting systems (and a sponsor of this report). “By harvesting rainwater, you’re reusing that water, and it’s not going into the treatment system. That relieves pressure on sewer and septic systems.”

Yet many states and local jurisdictions prohibit the indoor use of graywater and rainwater and limit their use at most to underground drip irrigation. NSF International, a product testing organization based in Ann Arbor, Mich., is drafting a standard on the water quality and O&M aspects of graywater to help clarify the health and safety aspects associated with reused water.9

In the following chapters we expand on the points hinted at here. Chapter 2 presents the results of two exclusive surveys. Chapter 3 explores what Building Teams are doing about indoor water performance; Chapter 4 looks at the exterior of buildings. Chapter 5 surveys the water components of the green building certification programs. Chapter 6 delves into water and energy.

We conclude with our Action Plan—21 specific recommendations on what AEC professionals, home builders, government agencies, trade associations, and the public can do to improve water performance.


  1. To download copies of past White Papers, go to: /university/community/934/White+Papers/47492.html

  2. “Freshwater Supply: States’ Views of How Federal Agencies Could Help Them Meet the Challenges of Expected Shortages,” U.S. General Accounting Office, GAO-03-514, July 2003.

  3. There is the further problem of “water gluttony.” A study of residential water use in Dallas, in 2005, found that the top 10% of homeowners used 34% of the city’s residential demand. The most gluttonous household used enough water to supply the indoor needs of 425 people. “Discussion: Are Water Managers Becoming Lawn Irrigation Managers?” Amy Vickers, Journal AWWA, February 2007.
    Even the age of homes may be a factor. A U.S. Environmental Protection Agency WaterSense survey of 18,000 homes, half of them built before 2001 and half built in 2001 or later, found that new homes in seven of nine cities under study used 40% more water than older homes. Why? New homes had more bathrooms, and this seemed to encourage use. “Can water efficient technology save us from ourselves?” Doug Bennett, Landscape Management, 9 September 2008. wwww.landscapemanagement.net/landscape/Green%20Industry%20News/Can-water-efficient-technology-save-us-from-oursel/ArticleStandard/Article/detail/548578?contextCategoryId=465
    *Boulder and Denver, Colo.; Eugene, Ore.; Las Virgenes (Calif.) Metropolitan Water District; Lompoc, Calif.; Phoenix; San Diego; Seattle; Tampa, Fla.; Tempe/Scottsdale, Ariz.; Walnut Valley (Calif.) Water District; and Waterloo/Cambridge, Ont.
    Aquacraft’s Peter Mayer: “The outdoor use component is strongly influenced by the the geography and climate of the cities that participated in the study. Outdoor use as a percent of the total ranged from 22-67% in this study. While the 58.7% outdoor use was the average for the participating agencies, these agencies are not representative of the entire U.S. It is an acknowledged weakness of the study.”

  4. “WaterView 2009 Report: Water & Wastewater Markets,” Environmental Business Journal (published by ZweigWhite), Summer 2009.

  5. “Water and Sustainability (Volume 4): Use Water Consumption for Water Supply and Treatment—The Next Half Century,” Electric Power Research Institute, Topical Report, March 2002.

  6. “The Carbon Footprint of Water,” Bevan Griffiths-Sattenspiel and Wendy Wilson, River Network, May 2009. www.rivernetwork.org The authors note further: “While this appears to be a conservative estimate of water-related energy use, our findings suggest that the carbon footprint currently associated with moving, treating, and heating water in the U.S. is at least 290 million metric tons a year. The CO2 embedded in the nation’s water represents 5% of all U.S. carbon emissions and is equivalent to the emissions of over 62 coal-fired power plants.”

  7. The Infrastructure Leakage Index provides a measure of how a water system is performing vs. best practices. An ILI of 3 would mean that the system is three times “leakier” than it should be. Presumably, new systems should have low ILIs; older systems, high indexes. ILI was first published by the International Water Association in 1999 and is in use in 50 countries.

  8. “Financing Water Infrastructure: A Water Infrastructure Bank and Other Innovations,” American Water Works Association, 26 February 2009, page 3.

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