Elsevier established a free COVID-19 resource centre in January 2020, offering English and Mandarin information on the virus. The centre is hosted on Elsevier Connect, and the company grants permission for free access to its research in PubMed Central and other repositories for research reuse. The article discusses the impact of microbial contamination in drinking water on health in developing regions. Poor water quality, sanitation, and hygiene contribute to 1.7 million annual deaths, mostly from infectious diarrhoea. Children are most affected, with nine out of ten deaths occurring in children and nearly all in developing countries. Major pathogens include rotavirus, Campylobacter jejuni, E. coli, Shigella, and Vibrio cholerae. These pathogens are often controlled by chlorination, but recontamination is a major issue. Emerging pathogens like Helicobacter pylori and Burkholderia pseudomallei are also significant in some regions. In adults, long-term effects of initial infections, such as myocarditis, diabetes, and cancers, are less understood. The paper reviews the significance of waterborne diseases in the global disease burden, focusing on major pathogen groups: helminths, protozoa, bacteria, and viruses. It highlights the importance of matching appropriate indicators for different pathogens and the need for improved water treatment and sanitation. The article discusses the historical context of waterborne diseases, including cholera and typhoid, and their transmission through contaminated water and food. It also covers other enteric bacterial pathogens, environmental bacterial pathogens, enteric viruses, and parasitic protozoa. These pathogens are responsible for significant health issues, particularly in developing regions. The paper concludes that unsafe water, poor sanitation, and inadequate hygiene are major health challenges in developing regions, with emerging issues related to climate change and microbial evolution posing additional risks. Despite efforts, pathogens will continue to be a major health issue, especially in developing regions.Elsevier established a free COVID-19 resource centre in January 2020, offering English and Mandarin information on the virus. The centre is hosted on Elsevier Connect, and the company grants permission for free access to its research in PubMed Central and other repositories for research reuse. The article discusses the impact of microbial contamination in drinking water on health in developing regions. Poor water quality, sanitation, and hygiene contribute to 1.7 million annual deaths, mostly from infectious diarrhoea. Children are most affected, with nine out of ten deaths occurring in children and nearly all in developing countries. Major pathogens include rotavirus, Campylobacter jejuni, E. coli, Shigella, and Vibrio cholerae. These pathogens are often controlled by chlorination, but recontamination is a major issue. Emerging pathogens like Helicobacter pylori and Burkholderia pseudomallei are also significant in some regions. In adults, long-term effects of initial infections, such as myocarditis, diabetes, and cancers, are less understood. The paper reviews the significance of waterborne diseases in the global disease burden, focusing on major pathogen groups: helminths, protozoa, bacteria, and viruses. It highlights the importance of matching appropriate indicators for different pathogens and the need for improved water treatment and sanitation. The article discusses the historical context of waterborne diseases, including cholera and typhoid, and their transmission through contaminated water and food. It also covers other enteric bacterial pathogens, environmental bacterial pathogens, enteric viruses, and parasitic protozoa. These pathogens are responsible for significant health issues, particularly in developing regions. The paper concludes that unsafe water, poor sanitation, and inadequate hygiene are major health challenges in developing regions, with emerging issues related to climate change and microbial evolution posing additional risks. Despite efforts, pathogens will continue to be a major health issue, especially in developing regions.