Drinking water Technology, Eawag, developed a method by which hazard maps could be produced for geogenic toxic substances in groundwater. This provides an efficient way of determining which wells should be tested. Parameters for drinking water quality typically fall within three categories: Physical and chemical parameters include heavy metals, trace organic compounds, total suspended solids (TSS), and turbidity. Microbiological parameters include Coliform bacteria, "E. coli", and specific pathogenic species of bacteria (such as cholera-causing "Vibrio cholerae"), viruses, and protozoan parasites. Chemical parameters tend to pose more of a chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and
Drinking water reserves clean drinking water is considered a luxury. The latest Canadian government of 2015 was to spend additional funds to fix the problem but has not had success. In 1990, only 76 percent of the global population had access to drinking water. By 2015 that number had increased to 91 percent. 89% of people having access to water from a source that is suitable for drinking - called "improved water source". In 1990, most countries in Latin America, East and South Asia, and Sub-Saharan Africa were well below 90%. In Sub-Saharan Africa, where the rates are lowest, household access ranges