Whitepaper:Water Conservation Best Management PracticesBy Amy Cornelius

Within the next 100 years…“Water will shape the full spectrum of economic, political and social trends, as well as how we make decisions. We will all begin to view water more as a precious resource rather than a free commodity to be exploited and wasted.” Steve Maxwell, The Future of Water: A Startling Look Ahead

ABSTRACTFreshwater, a critical resource that is necessary to support life on the planet, is facing a crisis that has far reaching implications for human health, productivity and peaceful existence. The design community has significant responsibility and opportunity to influence the management of both potable, freshwater and rainwater in buildings and their surrounding landscapes. Through design, conservation measures that dramatically reduce consumption can be introduced with little to no difference in occupant comfort and through the introduction of ‘new’ technologies such as graywater recycling and onsite infiltration of stormwater, water consumption and its treatment can be further reduced. The Best Practices detailed in the article provide a guide for designers.

Water Conservation Best Management Practices

Imagine you have a glass that is full of water. In that glass is all the water in, on and around the world, all 1.4 billion km³ of it. Only 2.5% of that water is considered freshwater. Of the 35 million km³ of freshwater: 70% is trapped in ice or snow 0.3% is in rivers and lakes .05% is in the atmosphere About 1% is usable fresh water – 350 thousand km³ or 0.03% of all the water in, on

and around the world.That is a limited resource!

Unlike oil, water isn’t finite. It replenishes itself through the earth’s climate cycle. Because of this it is often taken for granted. Also unlike oil, water is something all of nature needs to survive and something which we all have a very intimate relationship. We drink, bathe, swim in and enjoy water. The problem is that, given business as usual, in the next 20 years, world demand for fresh water will outpace supply by 40%. 1 Also unlike oil, water is seen as a local resource and is consumed and conserved based upon the perceptions of its availability in a particular area. It is not valued as a resource shared with other geographic locations let alone with the whole world. In the US this leads to unbalanced approaches in code development for water management, classification and treatment. The Water Footprint Network is attempting to change people’s and industry’s valuation of water and to highlight its value as a resource in the hopes of developing balanced policy. That, together with education, may provide incentives to conserve in the future. Designer’s have the ability to immediately influence consumption.

Right now the world’s 6.8 billion people use 54% of the usable fresh water. But, according to the UN, even without outpacing supply, distribution of freshwater around the world is unequal to the point that many have no access to water: 1.5 million people die every year because of lack of access to clean, potable freshwater and/or poor sanitation. 1.6 billion people have no access to sanitation. Half of the people in the world who suffer from malnutrition, suffer because of water borne and sanitation related issues2

These are startling numbers. For Americans though they seem like far off statistics - problems in another place. Americans need to wake up.

In October 2010 Wall Street 24/7 reported 3 the ten largest US cities (by population) that have the greatest chance of running out of water in the near future (less than 50 and in some cases 2-3 years): Orlando, Atlanta, Tucson, Las Vegas, Fort Worth, the San Francisco Bay Area, San Antonio, Phoenix, Houston and Los Angeles. These areas represent 6% of the US population. 4 This is in an era where we are working mightily to reduce sprawl by providing incentives to induce people to move to the cities.

According to the World Business Council for Sustainable Development, “If a supply-oriented approach is taken to meeting the coming (potable water availability) gap, up to US$ 200 billion in investments per year will be required up to 2030. However, focusing on demand-side measures can achieve the same effect for US$ 50 to US$ 60 billion per year. This approach obviously leads to cost savings.”5 Demand-side approaches are often times in the designer’s control. Given some simple design strategies, architects and designers have a tremendous opportunity to reduce water consumption and design ways for those in need to capture, store, clean and dispose of water in a safe manner.

According to the United States Geological Service, Americans use about 408 billion gallons of freshwater a day. 6 The Environmental Protection Agency calculates that average per household consumption of an existing house is 190 gallons per day (gphd). 7

The residential water consumption patterns within the EPA’s 190 gphd estimate suggest a guide for architects and designers to focus on when making design decisions and setting

water strategies for new construction and for renovation. Following are some recommended Best Practices that architects and designers can employ in residential construction and renovation. Based on an extensive review of conservation strategies developed and recommended by: certification organizations, water conservation groups, worldwide social organizations, trade groups and incorporated into municipal codes and policies, these Best Practices represent simple to specify and implement design elements that make major impacts. Labeled Residential Strategies (RS), the strategies can reduce water consumption and have the secondary impact of reducing household and utility electrical use. 8

Residential Water Consumption

Outdoor28%

Toilet19%Shower

12%

Faucet11%

Clothes Washer

16%

Leaks10%

Other4%

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BEST PRACTICES – RESIDENTIALMinimum = should be considered building standard. No added cost or short payback.Medium = not normal practice but easily part of a building system. Some added cost. High = not currently normal practice. Code allowed. Added cost ranges upon type of system.

RS 1: Minimum - Specify Water Sense Construction Methodologies and AppliancesThe EPA recently funded a study 10 which shows that significant inroads – a 42% decrease in consumption - can be made by specifying Water Sense standards (Appendix A – 2009 WaterSense Single-Family New Home Specification; EPA) for the whole house:

The Water Sense standard includes: Construction pipe leakage testing Maximum service pressure of 60 pounds per square inch Hot water delivery that reduces wait time for delivery to tap 1.28gpf toilets

oLEED Homes - High-Efficiency is <=1.3gpf; Very High-Efficiency is <=1.1gpf Faucet aerators at 0.8-1.5gpm

oLEED Homes - High-Efficiency is <=2.0gpm; Very High-Efficiency is <=1.5gpm Showerheads total flow rate in house of 2.5 gpm.

oLEED Homes - High-Efficiency is <=2.0gpm; Very High-Efficiency is <=1.75gpm Clothes Washers to be less than or equal to 6.0 gallons per cycle per cubic foot

capacity.

RS 2: Minimum - Specify Energy Star Construction Methodologies and AppliancesThe Water Sense specifications require Dishwashers and Clothes Washers be Energy Star and Water Sense labeled. Energy Star recently unveiled their “Most Efficient” designation. According the DOE, specifying Most Efficient Clothes Washers provides an ‘incremental improvement’ in energy efficiency. (Dishwashers are not included in this designation).

RS 3: Medium - High - Specify Purple Pipe Wastewater Installation for Graywater CaptureCapturing graywater from the building and reusing it reduces water consumption. The system collects water from tubs, showers, bathroom sinks, clothes washers and laundry sinks, stores it for less than a day and then reuses it for landscaping and/or for toilets. The International Association of Plumbing and Mechanical Officials has designated purple as the color for reclaimed/recycled and graywater water lines. There is some dispute about including graywater in the color purple as it mixes ‘clean’ reclaimed/recycled with water that may contain pathogens. Municipal codes should be checked for applicability.

Graywater should not be stored more than 24 hours to avoid microbial growth so balancing supply and demand in the system is critical. Calculating the water supply using the most constrained volumes that are based on Very High-Efficiency fixtures and demand on High-Efficiency fixtures provides a ‘worst case’ situation to analyze. Also, the system must be piped independently of the domestic potable system to avoid cross contamination. Makeup potable water should be piped to the storage tank with a backflow preventer to ensure adequate supply to the connected systems.11

Balancing can be tricky but the key is to ensure that the toilet demand is met; then any overage can go to landscaping. An example: A residence is designed with 2-1/2 baths and a laundry room. The fixture schedule calls for the Very High-Efficiency Level: aerators at flow rate 0.8gpm, Showerheads at flow rate 1.75gpm, Clothes Washer at flow rate 6.0 gallons per cubic foot and toilets at the construction standard of 1.6gpf.

In both cases – based on specification and based on EPA study volumes, there is sufficient outflow to meet the toilet demand. If toilets were also specified at the Very High-Efficiency Level, this supply volume would be more than adequate. The cost factors for such a system include: installation of the purple pipe system and the tank and treatment systems for the graywater. Tanks and treatment systems are beginning to be available in the US as kits offering ease of assembly, monitoring and maintenance and costs are beginning to come down. 12

I like the Nubian System for graywater reuse because it is low maintenance and all in one: http://www.nubian.com.au/Residential-Greywater-Treatment-System.asp

RS 4 : Minimum - Specify Regionally Appropriate, Drought Tolerant LandscapingDo not install irrigation. The Water Sense specifications detail irrigation system requirements but by specifying regionally appropriate, drought tolerant plants, limiting turf and educating the resident about why using potable drinking water is inappropriate for outdoor avoids the need to install an irrigation system and will reduce outdoor water consumption dramatically. If it is necessary to install an irrigation system because of client demand, using the rainwater capture and graywater systems as supply water sources meets the same consumption reduction goal.

RS 5: Minimum – Specify On-Site Infiltration of Stormwater

The Water Sense specifications detail landscaping requirements for steep slopes but do not address on-site infiltration. Looking at stormwater as a resource rather than a waste product and managing it as close to its source as possible is an example of low impact development. Designers can include raingardens, landscaped infiltration boxes and bioswales, vegetated rooftops and permeable paving in the landscape and site preparation specifications to reduce stormwater runoff; improving stream health and allowing for groundwater recharge at the site. 13 14

RS 6: Medium – Specify Rainwater Capture and Reuse SystemThe Water Sense specifications mention rainwater capture as a possible alternate. Specifying rainwater capture as part of the stormwater management program and as the source of water for an irrigation system and if possible clothes washing and toilets and makes it part of the house’s systems rather than an a-la-carte nicety that can be later discarded in budget discussions. Integrating rainwater capture into an irrigation system effectively cuts the 27% of potable water used outside to zero, saving approximately 53 gallons per household per day plus delivery and treatment electrical expenses. The rainwater system capacity and identification of possible water uses should be calculated during the design phase. Many municipal codes require a freshwater makeup system if the rainwater system is designed to serve interior uses such as toilets or clothes washing. Calculating Rainwater Potential

o Square Feet Surface x 0.623 per inch x Inches of rain = Gallonso Thumb Nail allowing for 20% loss:

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Example: The building’s roof is 1,500sf so, based on thumb nail estimates, the building can capture 825 gallons per 1” rain event. Outdoor usage is estimated at 53 gallons per day (gpd) and toilets are estimated to use 36 gpd. If usage is limited to these two purposes that allows 9 days of survivability. Adding the 30 gallons for the clothes washer reduces survivability to 6 days. Both situations would save water but both would require freshwater makeup. If the system was limited to outdoors, survivability is not an issue and no makeup would be required.

Some flexible methods for collecting and storing rainwater: o www.tufftechbags.com : Flexible bagso http://rainwaterhog.com/ : Can lie flat or act as a wall.o www.rainharvesting.com : Complete packageso Bushman: cool tanks

RS7: Minimum – Specify 100% Commissioning of Plumbing Equipment and PipingDesigning plumbing piping in chases or risers so that they are centrally located and easily accessed for repair and maintenance allows for ease of long term repair, upgrade and interior renovations. It also makes it easy to identify leaks. The Water Sense program specifies pressure testing installed piping prior to wall close-in.

RS8: Medium – Employ active solar hot water technologies.Utilizing a closed loop solar hot water system reduces electricity demand for heating and storing water in traditional hot water tanks. Although not a true water saver it is part of the system that serves the occupants and should be specified as part of the plumbing system’s first costs.

RS9: Minimum – Specify the use of FSC (Forest Stewardship Council) Certified WoodEncouraging the use of wood and wood products that are certified to be harvested substainably, protects watersheds and potable drinking water sources worldwide and provides an education moment for clients to know that their decisions here in the US are connected to a worldwide system.

RS10: Minimum – Medium – Insulate all hot and cold water piping to R5.5Insulating the hot water system reduces consumption by reducing the time required to bring hot water to the spigot and preserves the heat in the hot water through its run to the demand point. Insulating all piping is good practice for durability as it reduces condensation in walls thus reducing the probability of water damage, rot and mold forming within the walls. Recommend Nomaco Insulation FlexTherm product at ¾” for R5 insulation: http://www.nomacoinsulation.com/files/new/NI-0017-PS%200909%20FlexTherm.pdf

How do these best practices affect consumption? Assuming a Base Line of 190gphd and a design that calls for implementation of all of the listed Best Practices:

The design community has significant responsibility and opportunity to influence the management of both potable, freshwater and rainwater in buildings and their surrounding landscapes. By specifying these 10 Best Practices in the design documentation, the designers have the potential of reducing demand by 82% over the Baseline case handily beating the Water Sense reduction goal of 42%. Imagine the impact of these strategies when implemented over a series of homes; the potential for saving clean, potable water is dramatic.

Although not within the context of this paper, water management in commercial facilities and schools has the potential to save enormous amounts of potable water via these same 1 US State Department remarks form World Water Day 2011. Viewed April 2011.2 UN Water, http://www.unwater.org/statistics.html Accessed July 20113 24/7Wall Street, October 29, 1020 “The Ten Biggest American Cities That Are Running Out Of Water”, http://247wallst.com/2010/10/29/the-ten-great-american-cities-that-are-dying-of-thirst/ Accessed July 2011

4 Census/population data for the 10 cities. Note that the bay area includes the surrounding areas, the other data are for the cities proper. This undercounts the population at risk as the water service is to the SMA not just the city proper. http://www.bayareacensus.ca.gov/bayarea.htm, http://www.census.gov/popest/cities/tables/SUB-EST2009-01.xls: 235,860 Orlando, 540,922 Atlanta, 534,910 Tucson, 567,641 Las Vegas City, 3,831.868 Los Angeles City, 2,257,926 Houston City, 1,593,659 Phoenix City, 6,783,760 San Fransisco Bay Area, 727,577 Fort Worth, 1,296,682 San Antonio. Accessed July 2011.

5 Page 52 of Vision 2050; World Business Council for Sustainable Development. http://www.wbcsd.org/web/projects/BZrole/Vision2050-FullReport_Final.pdf Accessed July 2011

6 U.S. Geological Survey, “Estimated Use of Water in the United States 2000, Hutson, Susan S., Linsey, Kristen S., Kenny, Joan F., and Barber, Nancy L. http://pubs.usgs.gov/circ/2004/circ1268/index.html Accessed July 2011.

7 Analysis of Water Use in New Single Family Homes study was conducted by a team lead by Aquacraft, Inc. and funded by a consortium of nine water utilities and by a grant from the US EPA. http://www.aquacraft.com/projects. Accessed July 2011.

8 Water uses energy. Fine Homebuilding reports that, “Running cold water for five minutes consumes as much energy as a 60kw lightbulb does in 14 hours. It also requires energy to treat the water afterward. Nationally it takes an average of 0.0033 kWh of electricity to supply and treat each gallon.” (Fine Homebuilding Magazine Fall/Winter 2010). Currently, about eight percent of U.S. energy demand goes to treating, pumping, and heating water and is equal to enough electricity to power more than 5 million homes for an entire year. Water heating alone accounts for 19 percent of home energy use and 13 percent of the average utility bill. (US EPA, Office of Water: www.epa.gov/water/water_efficiency.html) $4 billion is spent annually in the US for energy to run drinking water and wastewater utilities. (EPA Energy Star for Wastewater Plants and Drinking Water Systems. http://www.energystar.gov/index.cfm?c=water.wastewater_drinking_water). This represents and enormous amount of waste and a tremendous opportunity for savings.

9 Buildings and their Impact on the Environment: A Statistical Summary, Revised April 22, 2009, www.epa.gov/greenbuilding. Accessed July 2011.10 . Analysis of Water Use in New Single Family Homes study was conducted by a team lead by Aquacraft, Inc . and funded by a consortium of nine water utilities and by a grant from the US EPA. http://www.aquacraft.com/projects. Accessed July 2011.

strategies. The Best Practice list can easily be expanded in these buildings to include blackwater treatment (see footnote 12), reuse/ recycling of treated water used in air conditioning systems and full treatment of rain water for potable use.

Other strategies will need to be implemented in less resource rich countries including desalination and innovative individual and community wide water filtration systems. The lessons learned and the strategies implemented here in the US can provide a basis for developing and implementing innovative solutions worldwide. It is imperative that the design community work together to educate clients and the public about the necessity of water conservation and the need to work as a world community for the health of us all.

11 Sheikh, Bahman, PhD, PA, “Whitepaper on Graywater”, 2010 published by the American Water Works Association, Water Environment Federation and the WateReuse Association. Accessed 2010.12 Note: Blackwater, or the treatment of toilet and kitchen sink water, is not included as a Best Practice here because it is a hot bed of controversy in local health departments. Decentralization of sewage treatment is feasible and is even required under Living Building Challenge criteria but it is disallowed by many health departments. This will change in the near future and then it should be added to the designer’s strategy arsenal.13 For more information on Low Impact Development see http://www.epa.gov/owow/nps/lid Accessed July 2011.

14 Residential Green Building Guide: A Web Source Book for The Pacific Northwest and Alaska, Office of Air, Waste and Toxics, US EPA, Region 10, EPA 910-K-09-006, August 2009. Appendix B.15 Bushman USA, “How Much Water Can I Collect?” www.bushmanusa.com Accessed Jan 2010

Definitions:

GPHD: Gallons per household dayGraywater: Graywater is untreated wastewater, excluding toilet and—in most cases—dishwasher and kitchen sink wastewaters. Wastewater from the toilet and bidet is "blackwater." Exclusion of toilet waste does not necessarily prevent fecal matter and other human waste from entering the graywater system—albeit in small quantities. Examples of routes for such contamination include shower water and bathwater and washing machine discharge after cleaning of soiled underwear and/or diapers. California's latest graywater standards define graywater thus:

... "graywater" means untreated wastewater that has not been contaminated by any toilet discharge, has not been affected by infectious, contaminated, or unhealthy bodily wastes, and does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes. "Graywater" includes but is not limited to wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs, but does not include wastewater from kitchen sinks or dishwashers. (California Building Standards Commission, 2009)16

Rain Gardens: Rain gardens look like traditional gardens, but usually consist of deep-rooted native plant species and have a bowlshaped dip in the center. They are used to absorb and filter rain as it runs off paved and other impervious surfaces on a home’s landscape. Because they are typically planted with native species, they require little maintenance once they are established.Water Footprint: The water footprint of an individual, community or business is defined as the total volume of freshwater that is used to produce the goods and services consumed by the individual or community or produced by the business.

Sources:Alliance for Water Efficiency; Website: http://www.allianceforwaterefficiency.orgWater Footprint Network http://www.waterfootprint.org/?page=files/homeAmerican Rainwater Catchment Systems Association; http://www.arcsa.org/American Water Works Association; http://www.drinktap.org/consumerdnn/Default.aspx?tabid=85UN Water; www.unwater.orgAlliance for Water Efficiency; http://www.allianceforwaterefficiency.org/water-efficiency-watch-may-2011.aspx#a_new_studyForest Stewardship Council; www.fscus.orgInternational Green Construction Code; http://www.iccsafe.org/cs/IGCC/Pages/IGCCDownloadV2.aspxEPA Green Building; http://www.epa.gov/greenbuilding/index.htm

16 Sheikh, Bahman, PhD, PA, “Whitepaper on Graywater”, 2010 published by the American Water Works Association, Water Environment Federation and the WateReuse Association. Accessed 2010.

AppendixAppendix A: 2009 WaterSense Single-Family New Home Specification; EPA

Endnotes