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Rainwater Recycling in Modern Homes and Hospitals

Resilient Societies

Environmental Stewardship

Most people turn on the faucet and let fresh water flow without considering its source or the potential that it might run dry.

rainwater streaming into barrel from drain pipe

However, as droughts become more common and severe, water rationing is becoming a reality for more Americans, including those in Central Texas. Water scarcity poses a particularly grave problem for hospitals, which are the most intensive consumers of water among all large commercial buildings. Dr. Larry Fulton says, “We treat the environment like the water is always going to be there,” but as scarcity worsens that attitude will be difficult to maintain. According to Fulton, an associate professor of health administration, the solution is the same for both hospitals and personal consumption, and it is as clear as rainwater. 

Dr. Larry Fulton

Rainwater harvesting is both a personal and professional interest for Fulton because, as he puts it, “I research what I love.” Specifically, Fulton has a longstanding interest in the intersection of sustainability, finance, and healthcare. When Fulton retired from the Army Medical Department in 2010, he endeavored to use his own home as a test case to research sustainability’s practical and financial viability. “Done well,” he argues, “sustainability can generate a return on investment. I am green for the pocketbook, as well as for the environment. I engineered and built my home to be sustainable from the ground up, meaning that I would not have an electric or water bill.”

Fulton eliminated his need for city water by installing a rainwater capture, purification, and delivery system. His results were impressive, so he published them. Even in arid San Antonio, he satisfies 100 percent of his household’s water needs with rainwater, the level in his cistern never drops below 75 percent, and he eliminated his water bill. This success led him to his next research question: How could his household system be scaled up for maximum impact? Fulton’s experience working in medical systems made the answer obvious. 

150 gallons per day - average American’s daily use of city water


0 gallons per day - city water used by household with rainwater harvesting system

Hospitals are notoriously thirsty. In addition to drinking water and landscape irrigation, hospitals use an immense amount of water for cleaning. For every staffed bed, hospitals use an average of 570 gallons of water daily, compared to the average American’s daily use of 150 gallons (which dwarfs the usage of an average Briton, 44 gallons). 

gloved hand cleaning hospital equipment

Fulton’s most recent research, published in Sustainability, used 71 years of historical data to assess rainwater’s potential to meet the water needs of hospitals in his hometown of San Antonio. The results of his research bear out the viability of using rainwater to supplant a substantial part of hospital water usage.

Even using conservative assumptions, Fulton concludes that hospitals could replace a quarter of their water supply with water capture systems equivalent in size to the buildings’ footprints, such as rooftop systems, whether constructed at the initial building stage or through retrofitting. In combination with conservation efforts, such as low-flow technology and reuse of grey water (typically used for toilets or landscape irrigation), the impact could be even greater. 

570 gallons per day - city water used per staffed bed in hospitals daily 

Rainwater harvesting would have many benefits for hospitals beyond the alleviation of scarcity-related risks. Rainwater is free, so after the systems are constructed their use would result in major cost savings. Purified rainwater is particularly good for hospital use, because it is a zero-hardness, zero-salt solution, and contains none of the pharmaceuticals and hormones commonly found in city water.

This purity is good for patient health and allows equipment that uses water to last longer. Finally, in addition to preserving aquifers, rainwater collection benefits the environment by reducing runoff and non-point source pollution, saving electricity used in the distribution, purification, and desalination of water in city systems, and maximizing the efficiency of consumption due to a high capture rate.

rain on house

Despite all of these advantages, Fulton says widespread implementation of rainwater harvesting systems, in households or hospitals, requires making the systems’ construction more affordable. “Once large-scale rationing occurs in San Antonio, the need is going to hit us in the face, but you can’t have a green intervention if it’s not green for people’s pocketbooks as well.”

Outside the United States, this strategy is already gaining traction. In India, for example, hospitals are required to harvest rainwater. In other countries, like Korea, some commercial buildings use rainwater to replace grey water. Fulton warns that the United States needs to catch up. A 2018 drought in Capetown, South Africa (a city with rainfall equivalent to San Antonio) resulted in water being restricted to around 13 gallons per person per day, less than 10 percent of what the average American uses. In arid regions like Texas, rainwater capture, combined with conservation, may be our only hope of avoiding a similar fate.

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