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Domestic Water Conservation

Introduction

New Jersey frequently suffers from both surface-water and groundwater drought conditions. In July 2010, the commissioner of the New Jersey Department of Environmental Projection issued a statement asking residents to voluntarily conserve water in light of extended dry conditions. Princeton University takes its responsibility to conserve water very seriously at all times, even during non-drought conditions.

Figure 12: Residence Hall Water Usage

Residence hall water usage has declined by 24 percent since 2007 — nearing the Sustainability Plan goal almost a decade early — due to low-flow fixture installation and new, efficient clothes washing machines.

Goals & Progress

  1. Goal: Reduce overall campus water usage compared to 2001 by 25 percent by 2010.*

    Progress:
    • Overall campus water usage has decreased by 27 percent since 2001, surpassing its goal due to combined efforts on campus and in the central plant (cogeneration and chilled water). Campus water usage has declined by 11 percent since 2007.
    • The University nearly has surpassed its goal to reduce water usage by 25 percent in residence halls by 2020. Water usage in all residence halls has declined by 24 percent (12 million gallons) compared to the 2007 baseline (since the adoption of the Sustainability Plan), due to the installation of low-flow fixtures and efficient clothes washing machines, among other water-saving measures (see graph above).
    • In addition to Princeton's standard low-flow fixtures in all residence halls, Brown Hall recently was retrofitted with the next generation of low-flow 1.28 gallons-per-flush (gpf) toilets. Installation of low-flow aerators, low-flow shower heads and dual-flush toilets continues in athletic facilities and academic and administrative buildings.
    • Dining Services has successfully implemented "tray-free" dining in five of six dining halls. For all dining halls, tray-free dining has the potential to reduce water and energy costs by $4,000 per year. 
    • Efficient new dishwashers have been installed in five of six dining halls, each saving about 300,000 gallons of water per year, or a total of 1.5 millions gallons — more than enough to fill two Olympic-size swimming pools.
    • To reduce the demand on domestic water supplies, the University has installed a rainwater storage and reuse system at the new Frick Chemistry Laboratory (see sidebar figure). It includes a 12,000-gallon underground storage tank that joins a 6,000-gallon cistern installed at Butler College in 2009.

      *The goal stated in 2009 (to reduce water usage in the residence halls by 25 percent by 2020) has been more aggressively revised to a more immediate deadline and to include all campus water usage, with the residential halls component as a sub-goal.
  2. Goal: Track and reduce potable water use for irrigation.

    Progress: Installation of computer-driven ("soil moisture" meters) at Holder Hall and Whitman and Butler colleges to track water usage in various areas, such as high-impact Reunions sites.
     

What's Next

Short Term

  • Support behavior-changing water conservation initiatives through student organizations such as the Eco-Reps, Greening Princeton and WaterWatch.
  • Continue to assemble and track data indicating the acreage of areas planted with drought-resistant or native varieties.
  • Evaluate effectiveness of 1.28 gpf toilets in Brown Hall renovation.

Long Term

  • Complete low-flow bathroom fixture replacements in athletic facilities, and academic and administrative buildings, including retrofitting 3.5 gpf toilets with 1.28 gpf fixtures in residence halls.* 
  • Continue to evaluate drought-tolerant lawn species.

*As an interim conservation effort, current 3.5 gpf toilets in residence halls are retrofitted with dual-flush valves.

"The 27 percent water savings we've achieved at Princeton since 2001 as a result of low-flow fixtures and other water-saving initiatives is a great example of when being green can save green. The proof is in the bills."
—Timothy Downs, manager, Budget and Finance, Facilities Finance and Administrative Services


Low-flow faucet

Since 2007, Wayne Meyer and his team in the Plumbing Shop have installed hundreds of low-flow fixtures in dormitories, administrative buildings and athletic facilities.

 

Figure 13: Water Collection at Frick Chemistry Laboratory


This drawing of the Frick Chemistry Laboratory shows how rainwater is collected on the roof of the building, and condensate is collected from mechanical systems in the "penthouse." The water is stored underground in a 12,000-gallon cistern, and is treated and reused for toilet flushing through high-efficiency, automatic flush valves. Data on stormwater and condensate collection and usage is then analyzed and fed to a video display in the atrium, along with data on photovoltaic panel production and fume hood energy consumption. Click to enlarge.