El Nino Preparedness: How Safe is Rain Water?

During the rainy season, many people use the water that is harvested indiscriminately. This may be mainly due to a lack of awareness about the risks that may be inherent in rainwater. Whereas some risk factors are atmospherically derived, many are acquired during the collection process and storage. In this exposition, a range of variables are examined to elucidate the possible risks that may arise from using harvested rainwater. Harvesting and use of rainwater are viewed from three frontiers namely; atmospheric contaminants, roofing material-derived contamination, and storage.

In the atmosphere, there are unlimited toxicants that are anthropogenically and naturally generated. At the same time, the rate of global climate change is rapidly modifying the rate of interaction between different ecosystems. Manmade contaminants are produced by industries and mining activities. Studies have reported that there are long-lasting organic pollutants in the atmosphere that rainwater can carry into harvesting facilities. Examples of such chemicals that have been characterized include; PFAs and several forever chemicals. Meteorological parameters may determine the bacterial composition of rainwater due to airborne microorganisms. For example, studies have reported that the bacterial load in rainwater is a function of wind velocity while the composition of microorganisms varies with wind direction. This could be due to increased aerodynamics impacting organisms from sources and the landing of many microbes at the roof catchment surface. During dry antecedent periods, dust, aerosols, and gases from the atmosphere can be directly transferred by deposition to tanks via utility openings. The length of dry antecedent conditions influences the quantity of accumulated substances that are washed from roofs into rainwater reservoirs. Longer dry antecedent periods are generally associated with higher bacterial counts due to the accumulation of inorganic particulate materials, organic matter and fecal droppings on the roof catchment. There is incontrovertible evidence that some of the substances identified are known carcinogens, teratogens, and mutagens.

The antecedent periods of the rain season provides conditions that result in the deposition of organic, inorganic and biological material on the rainwater harvesting infrastructure. Many citizens dwelling in the LMICs are oblivious to the risk posed by roofing materials to their rainwater. Indeed some people use rainwater for drinking and cooking food. This should not be the case as some of the roof catchment may have toxic chemicals. For instance, some residences in the LMICs still have Asbestos roofs. This is in spite of global efforts to reduce and eventually interdict exposure to Asbestos. The role of climate change is prominent since climatic-induced emergencies intensify exposure to several toxicants. The rate and intensity of exposure is contingent on the geographical location and the urbanization status of residential areas.     

In the storage facility, several processes occur, including the decomposition of organic materials that are collected from the atmosphere and the roof catchment milieu. From the outset, the chemical toxicants that are dissolved in the atmospheric air remain potent and pose the risk of disease causation. Cases of acute poisoning have been reported in heavily polluted cities and mineral processing regions. Chronic and invisible exposure is commonplace and sustains the long-term disease burden associated with rainwater use. Apart from the direct risk posed by individual compounds that are present in the water, there is the likelihood of chemical reactions with subsequent deleterious health-related legacy. Studies have shown that some of the progeny of derived compounds are more toxic than their parents. Accordingly, rainwater may exhibit varying grades of toxicity after storage due to such chemical interactions. Importantly, some of the chemicals are long-lasting and many years of water reservoir use may have increased the probability of acute exposure. Therefore, users of rainwater harvesting reservoirs are advised to ensure seasonal evacuation of residual material during antecedent dry seasons.

At this point, it is important to examine the dynamics associated with antibiotic resistance. Studies have reported that rainwater may contain fecal material and associated bacteria, fungi, and viruses. Since roofs are elevated, many aves and arboreal creatures use the water catchment canopy as their home ranges and for mating. As such the risk of zoonotic and opportunistic disease exposure is paramount. The long-term exposure of bacteria to various compounds may have a mutagenic effect leading to increased bacterial mutation. At the same time, given that most water in such reservoirs are not exposed to UV, there is an artificial pathogenic ecosystem that is created. As such, drug resistance is modulated through several rounds of exposure to chemical toxicants in the water. This may explain the sudden outbreak of bacterial diseases in schools and facilities hosting cohorts of residents.

Drinking water guidelines are used to assess the microbial quality of the rainwater when used for drinking. Guidelines such as World Health Organization (WHO), Japanese and EU drinking water guidelines require that E. coli should not be detected in a 100 mL sample of drinking water, and if detected, remedial action should be executed to limit human health risks. Escherichia coli bacteria are commonly present in the feces of warm-blooded animals in significant populations. Accordingly, their occurrence in a water source indicates evidence of fecal contamination and potential enteric microbes. Most research studies on rainwater reported to date used Escherichia.coli to determine the microbiological quality of the water. Given the foregoing state of affairs, several remedial measures have been recommended for dealing with the challenges that are associated with rainwater-related risks namely; water catchment maintenance, water reservoir hygiene, and water treatment through exposure to UV or chemical processing to reduce inherent toxins and toxicants. Some researchers have demonstrated that reducing exposure to such water is most effective for preventing related pathogenic outcomes. It is important to note that many LMICs lack facilities for removing non-biological materials from rainwater.    

Recommended further reading

"82(R) H.B. No. 3391. An act relating to rainwater harvesting and other water conservation initiatives. † went into effect on September 1, 2011". 82nd Regular Session. Texas Legislature Online. Retrieved 8 February 2013.

"Believes in past, lives in future". The Hindu. India. 17 July 2010. Archived from the original on 9 October 2012.

"CANARM.org - Canadian Association for Rainwater Management". www.canarm.org. Retrieved 2016-03-22.

"Criteria and Guidelines for the "Rainwater Harvesting"" (PDF). Pilot Project Program. Colorado Water Conservation Board (CWCB). January 28, 2010. Archived from the original (PDF) on 2016-03-05. Retrieved 2012-03-24.

"Harvesting rainwater for domestic uses: an information guide" (PDF). Environment Agency. October 2010. Retrieved 2021-01-23.

"Harvesting rainwater for more than greywater". SmartPlanet. Archived from the original on 10 May 2013. Retrieved 13 November 2014.

"Homepage - Water, Septic Tanks and Rainwater Harvesting Systems Canada - Clean-Flo Rainwater Management". Water, Septic Tanks and Rainwater Harvesting Systems Canada - Clean-Flo Rainwater Management. Retrieved 2016-03-22.

"India Rainwater Harvesting Market, By Type (Rain Barrel System, Dry System, Wet System, Green Roof System), By Harvesting Method (Above Ground {Ground Surface and Storage Tank}, Under Ground), By Application (Residential, Commercial, Industrial and Agricultural), By Region, By Competition Forecast & Opportunities, 2018-2028". TechSci Research.

"Inverted Umbrella Brings Clean Water & Clean Power To India". 2017-12-04. Archived from the original on 2018-07-09. Retrieved 5 December 2017.

"Lanka Rain Water Harvesting Forum (LRWHF)". Archived from the original on 2015-02-03. Retrieved 2011-12-09.

"Learning legacy: Lessons learned from the London 2012 Games construction project" (PDF). Olympic Delivery Authority. 2011. Archived (PDF) from the original on 2015-12-08. Retrieved 2018-04-24.

"Low cost drinking water technology – rainwater harvesting with solar purification. Current Science, Vol. 118, No.6, 25 March 2020" (PDF). Archived (PDF) from the original on 19 January 2022. Retrieved 27 March 2020.

"New rooftop solar hydro panels harvest drinking water and energy at the same time". 29 November 2017. Archived from the original on 2019-08-10. Retrieved 2017-11-30.

"Parliament Of The Democratic Socialist Republic of Sri Lanka" (PDF). Archived from the original (PDF) on 2013-11-04. Retrieved 2011-12-09.

"Rain fed solar-powered water purification systems". Archived from the original on 21 October 2017. Retrieved 21 October 2017.

"Rain Water Harvesting by Freshwater Flooded Forests". Archived from the original on 2016-03-05. Retrieved 2018-07-09.

"Rain water Harvesting". Tamil Nadu State Government, India. Archived from the original on 12 August 2019. Retrieved 23 January 2012.

"Rainwater Collection in Colorado" (PDF). Colorado water law, notices. Colorado Division of Water Resources. Archived from the original (PDF) on 2016-03-06. Retrieved 2012-03-24.

"Rainwater Filters". Rainharvesting Systems. Retrieved 2017-03-08.

"Rainwater Harvesting - Controls in the Cloud". SmartPlanet. 2013-10-03. Archived from the original on 2019-08-05. Retrieved 11 January 2015.

"Rainwater Harvesting for Livestock". www.ntotank.com. Archived from the original on 2018-11-21. Retrieved 2018-11-21.

"Rainwater harvesting in Germany". www.rainwaterharvesting.org. Archived from the original on 2019-02-19. Retrieved 2018-04-24.

"Rainwater harvesting". Archived from the original on 2019-05-08. Retrieved 2016-03-03.

"Rainwater harvesting". SVCwater. Retrieved 2013-07-27.

"Rainwater harvesting". www.wrc.org.za. South African Water Research Commission. Archived from the original on 28 October 2018. Retrieved 27 August 2014.

"Rainwater tanks". Greater Wellington Regional Council. 28 April 2016. Archived from the original on 14 April 2016. Retrieved 21 March 2017.

"Rare Chola inscription found near Big Temple". The Hindu. India. 24 August 2003. Archived from the original on 22 November 2003.

"State Rainwater Harvesting Statutes, Programs and Legislation". NCSL. Archived from the original on 8 October 2013. Retrieved 7 February 2013.

"Understanding the Kenya 2016 Water Act" (PDF). 2030wrg. Archived (PDF) from the original on July 26, 2021. Retrieved July 26, 2021.

"Water Supply Systems: Cisterns, Reservoirs, Aqueducts | Roman Building Technology and Architecture, University of California Santa Barbara". ArchServe. Archived from the original on 2016-07-18. Retrieved 2018-04-13.

Bibliography

Amos, Caleb Christian; Rahman, Ataur; Karim, Fazlul; Gathenya, John Mwangi (November 2018). "A scoping review of roof harvested rainwater usage in urban agriculture: Australia and Kenya in focus". Journal of Cleaner Production. 202: 174–190. doi:10.1016/j.jclepro.2018.08.108. ISSN 0959-6526. S2CID 158718294.

Bagel, Ravi; Stepan, Lea; Hill, Joseph K.W. (2017). Water, knowledge and the environment in Asia : epistemologies, practices and locales. London. ISBN 9781315543161.

Behzadian, k; Kapelan, Z (2015). "Advantages of integrated and sustainability based assessment for metabolism-based strategic planning of urban water systems" (PDF). Science of the Total Environment. 527–528: 220–231. Bibcode:2015ScTEn.527..220B. doi:10.1016/j.scitotenv.2015.04.097. hdl:10871/17351. PMID 25965035.

Braga, Andrea. "Making Green Work, and Work Harder" (PDF). Geosyntec. p. 5. Archived from the original (PDF) on 4 March 2016. Retrieved 30 November 2014.

Button, Cat (2017-05-04). "Domesticating water supplies through rainwater harvesting in Mumbai". Gender & Development. 25 (2): 269–282. doi:10.1080/13552074.2017.1339949. ISSN 1355-2074.

Cain, Nicholas L. (2014). "A Different Path: The Global Water Crisis and Rainwater Harvesting". Consilience (12): 147–157. ISSN 1948-3074. JSTOR 26476158. Archived from the original on 2021-08-10. Retrieved 2020-11-26.

Centers of Disease Control and Prevention (CDC), 2013 Retrieved from https://www.cdc.gov/healthywater/drinking/private/rainwater-collection.html Archived 2020-04-06 at the Wayback Machine

Chen, Xuefei (27 August 2007). "Rainwater harvesting benefits farmers in Gansu". People's Daily Online. Archived from the original on 20 October 2012. Retrieved 10 July 2018.

Collecting and Using Rainwater at Home. Canadian Housing and Mortgage Corporation. 2013.

Devkota, J.; Schlachter, H.; Anand, C.; Phillips, R.; Apul, Defne (November 2013). "Development and application of EEAST: A lifecycle-based model for use of harvested rainwater and composting toilets in buildings". Journal of Environmental Management. 130: 397–404. doi:10.1016/j.jenvman.2013.09.015. PMID 24141064.

Devkota, Jay; Schlachter, Hannah; Apul, Defne (May 2015). "Life cycle based evaluation of harvested rainwater use in toilets and for irrigation". Journal of Cleaner Production. 95: 311–321. doi:10.1016/j.jclepro.2015.02.021.

Duke, Katie (2014). "Ownership of Rainwater and the Legality of Rainwater Harvesting in British Columbia". Appeal. Retrieved 2016-03-29.

Everson C, Everson TM, Modi AT, Csiwila D, Fanadzo M, Naiken V, Auerbach RM, Moodley M, Mtshali SM, Dladla R (2011). Sustainable techniques and practices for water harvesting and conservation and their effective application in resource-poor agricultural production through participatory adaptive research : report to the Water Research Commission (PDF). Gezina [South Africa]: Water Research Commission. p. 89. ISBN 978-1-4312-0185-3. Archived from the original (PDF) on 2014-12-31. Retrieved 27 August 2014.

Fletcher-Paul, Dr. Lystra. "Feasibility Study of Rainwater Harvesting for Agriculture in the Caribbean Subregion" (PDF). FAO. Archived (PDF) from the original on 2018-04-25. Retrieved 2018-04-25.

Furumai, Hiroaki (2008). Recent application of rainwater storage and harvesting in Japan.

Harry Low (December 23, 2016). "Why houses in Bermuda have white stepped roofs". BBC News. Archived from the original on 2016-12-23. Retrieved 2016-12-23.

Hatch, Jacob. "The Many Benefits of Rainwater Harvesting". Hydration Anywhere. Archived from the original on 13 December 2016. Retrieved 3 August 2018.

Ibrahim, Gaylan Rasul Faqe; Rasul, Azad; Ali Hamid, Arieann; Ali, Zana Fattah; Dewana, Amanj Ahmad (April 2019). "Suitable Site Selection for Rainwater Harvesting and Storage Case Study Using Dohuk Governorate". Water. 11 (4): 864. doi:10.3390/w11040864. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Archived 2017-10-16 at the Wayback Machine.

JMP (2016). "Joint Monitoring Programme Thailand Data". Retrieved 2017-03-13.^{[permanent dead link]}

Johari, Aarefa. "Mumbai could save water through its mandatory rainwater harvesting rule – but no one seems to care". Scroll.in. Retrieved 2023-05-12.

Johnson, Kirk (June 28, 2009). "It's Now Legal to Catch a Raindrop in Colorado". The New York Times. Retrieved 2009-06-30.

Kamash, Zena (2010). Archaeologies of Water in the Roman Near East. Gorgias Press.

Kinkade-Levario, Heather (2007). Design for Water : Rainwater Harvesting, Stormwater Catchment, and Alternate Water Reuse. Gabriola Island, B.C.: New Society Publishers. p. 27. ISBN 978-0-86571-580-6.

Kumar, M. Dinesh; Ghosh, Shantanu; Patel, Ankit; Singh, Om Prakash; Ravindranath, R.; Kumar, M. Dinesh; Ghosh, Shantanu; Patel, Ankit; Singh, Om Prakash; Ravindranath, R. (2006). Kumar, M. Dinesh; Ghosh, Shantanu; Patel, Ankit; Singh, Om Prakash; Ravindranath, R. (eds.). "Rainwater harvesting in India: some critical issues for basin planning and research". Land Use and Water Resources Research. doi:10.22004/ag.econ.47964.

Kumar, Ro. "Collect up to 10 gallons of water per inch of rain with Rainsaucers' latest standalone rainwater catchment". LocalBlu. Archived from the original on 17 December 2012. Retrieved 11 February 2013.

Lange, J.; Husary, S.; Gunkel, A.; Bastian, D.; Grodek, T. (2012-03-06). "Potentials and limits of urban rainwater harvesting in the Middle East". Hydrology and Earth System Sciences. 16 (3): 715–724. Bibcode:2012HESS...16..715L. doi:10.5194/hess-16-715-2012. ISSN 1607-7938. Archived from the original on 2022-07-10. Retrieved 2020-11-28.

Less, C. & Andersen, N. (1994). "Hydrofracture: State of the art in South Africa". Hydrogeology Journal. 2 (2): 59–63. doi:10.1007/s100400050050.

Lunduka, Rodney (2011). ECONOMIC ANALYSIS OF RAINWATER HARVESTING AND SMALL-SCALE WATER RESOURCES DEVELOPMENT. Retrieved 2020-11-25. {{cite book}}: |website= ignored (help)

Managing Urban Stormwater: Harvesting and reuse (PDF) (Report). Sydney, Australia: New South Wales Department of Environment and Conservation. 1 April 2006. ISBN 1-74137-875-3. Archived from the original (PDF) on 2020-07-16.

Mays, Larry; Antoniou, George & Angelakis, Andreas (2013). "History of water cisterns: Legacies and lessons". Water. 5 (4): 1916–1940. doi:10.3390/w5041916.

O'Brien, Sara Ashley (2014-11-11). "The Tech Behind Smart Cities - Eliminating Water Pollution". CNN Money. Archived from the original on 2014-11-14. Retrieved 13 November 2014.

Pearce, Fred; Mackenzie, Debora (3 April 1999). "It's raining pesticides". New Scientist. No. 2180. Archived from the original on 10 July 2018. Retrieved 10 July 2018.

Rural Water Supply Network. "Rural Water Supply Network Self-supply site". www.rural-water-supply.net/en/self-supply. Archived from the original on 2019-01-14. Retrieved 2017-03-19.

Saladin, Matthias (2016). "Rainwater Harvesting in Thailand - learning from the World Champions". Archived from the original on 2019-01-29. Retrieved 2017-03-13.

Staddon, Chad; Rogers, Josh; Warriner, Calum; Ward, Sarah; Powell, Wayne (2018-11-17). "Why doesn't every family practice rainwater harvesting? Factors that affect the decision to adopt rainwater harvesting as a household water security strategy in central Uganda". Water International. 43 (8): 1114–1135. doi:10.1080/02508060.2018.1535417. ISSN 0250-8060. S2CID 158857347.

Staddon, Chad; Rogers, Josh; Warriner, Calum; Ward, Sarah; Powell, Wayne (17 November 2018). "Why doesn't every family practice rainwater harvesting? Factors that affect the decision to adopt rainwater harvesting as a household water security strategy in central Uganda". Water International. 43 (8): 1114–1135. doi:10.1080/02508060.2018.1535417. S2CID 158857347.

Zhu, Qiang; et al. (2015). Rainwater Harvesting for Agriculture and Water Supply. Beijing: Springer. p. 20. ISBN 978-981-287-964-6.