Sources have stated that every year on March 22, the United Nations observes World Water Day to highlight the global water crisis. This year the focus is on reducing and reusing wastewater from homes, farms, factories and other sources.

Ensuring access to water and sanitation for all people is one of the U.N’s Sustainable Development Goals, adopted in 2015 by the United States and 192 other nations. Specifically, the goals call on member nations to “improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.”

The untreated sewage is a major threat to human health. According to the World Health Organization, unsafe water, poor sanitation and hygiene cause approximately 842,000 deaths each year, and 1.8 billion people use drinking water sources contaminated with feces. Contamination in Rio de Janeiro’s harbors and marinas, which were settings for aquatic events during the 2016 Summer Olympic Games, spotlighted the serious health risks associated with exposure to sewage. According to Joan Rose, laboratory director and principal investigator in water research at Michigan State University, human waste contains a wide range of bacteria, viruses and other pathogens.

Many communities in water stressed areas are considering ways to reuse water after it has been appropriately treated. A 2016 study by the National Academies of Sciences, Engineering and Medicine evaluated uses for so called gray water from bathroom sinks, showers, bathtubs, clothes washers and laundry sinks, but not from toilets or kitchens. It concluded that using gray water for purposes other than drinking, such as flushing toilets, could expand local water supplies and provide a drought-resistant year round local water source.