Water Conservation Case Studies

The following case studies show how companies have practiced water conservation. For more money-saving ways to conserve water, visit water conservation in waste less at agencies & schools.

conserving water on campus
using condensation and rainwater to cool building
low-flow restroom fixtures cut water and sewer costs

Conserving water on campus

Columbia University has converted most of its buildings to low-flow plumbing and has replaced miles of leaky pipes. The university has also replaced its hot water heaters with highly efficient systems and has metered most of its housing stock. Read more about their water conservation projects.

Using condensation and rainwater to cool building

The Ford Foundation, founded in 1936, is a charitable foundation with approximately four hundred employees headquartered in a 14-floor, 287,000-square-foot building near the United Nations.

The Ford Foundation uses water from steam condensation, condensate off cooling coils, and roof drains to supply cooling towers and provide garden irrigation. Rain runoff flows into a 3,000-gallon and 13,000-gallon tank. The 3,000-gallon tank is used for watering plants and trees in the building’s atrium. Approximately 900 gallons per week are used to water atrium vegetation. This tank is easily replenished from the cooling tower condensate and/or rainwater within one day of use.

The 13,000-gallon tank is used for the cooling towers. Warmer summers that require more work of the cooling towers to maintain the building temperature create more condensation, and thus more water for the tanks. This keeps the tanks almost always full. When tanks do get low, the Foundation resorts to using water from the New York City water system. The Foundation receives a credit, instead of a charge, from the City for this water because it is evaporated, rather than sent into the sewer system.

Source: Conversation with Ford Foundation facilities management, Summer 2003

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Low-flow restroom fixtures cut water and sewer costs

The Port Authority of NY & NJ at LaGuardia Airport (PA-LGA), a partner in the NYC Wastele$$ Business Project, is installing low-flow water devices as restrooms are renovated. PA-LGA has renovated approximately 78 percent of its restroom fixtures. As part of the ongoing renovations, PA-LGA implemented a water conservation program, which involved the following initiatives:

• Established a leak detection and prevention program to reduce wasted water. A faucet drip or invisible leak in the toilet could result in up to 15 gallons of wasted water per day, or 5,475 gallons of wasted water per year.

• Installed low-flow toilets. Ultra-low-flow toilets use only 1.6 gallons of water per flush. Older toilets use 3.5 to 5 gallons per flush.

• Installed high-efficiency, low-flow faucets and aerators on all faucets. These use water at a rate of 0.5 gallons per minute (gpm), as compared to standard faucets, which use 3 gpm.

• Installed flow restrictors on all showerheads. Each showerhead was reduced from a 4.5 gpm shower head to high performance 2.5 gpm models.

The following table shows a brief cost analysis of the water conservation initiatives undertaken at LaGuardia Airport.

1. Low-flow showerheads, faucet/aerators, and auto-flush toilets, respectively, cost approximately $25, $302, and $225 each.
2. Low-flow showerheads reduce water use from 4.5 to 2.5 gpm (44 percent). Ten showerheads have been replaced. Typical shower usage is 30 showers per day for five minutes, 365 days per year.
3. Low-flow auto-flush faucets reduce water use from 3 to 0.5 gpm per fixture (83 percent). As of spring 2003, 160 of 228 (70 percent) low-flow faucets have been installed. Typical faucet usage is once per passenger for 10 seconds. Approximately 22 million passengers visit the airport yearly.
4. Low-flow auto-flush toilets reduce water use from 3.5 to 1.6 gpm per fixture per flush (54 percent). As of spring 2003, 183 of 223 (82 percent) low-flow toilets have been installed. The number of toilet flushes per day is based on the assumption that all visiting passengers flush the toilet once. It is assumed that the male/female ratio of passengers is 50/50 and 50 percent of male passengers will only use a urinal. This makes the base figure for the number of toilet flushes a year 16.5 million.
5. Water reduction rates for urinals are not included in calculations because data on usage rates was not available. As of spring 2003, 89 out of 104 (86 percent) urinals have been replaced.
6. Water costs are $12.50 per 1,000 cubic feet. Number of cubic feet = number of gallons x 0.1337
7. Sewage treatment costs are 159 percent of water costs or $19.88 per 1,000 cubic feet. Number of cubic feet = number of gallons x 0.1337
8. Payback period is Total cost of fixtures/savings x 12.

Source: NYC WasteLe$$ Business Project findings and conversation with Port Authority at LaGuardia Airport facilities management, Spring 2003

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