Microbial organic and inorganic contaminants cannot always be detected by human senses. You might go years before realizing a problem exists. Many folks never become suspicious until people in the community start to get sick. Water near agricultural areas may contain harmful organic material from pesticide or fertilizer application. Chemicals from pesticides and fertilizers in water may increase cancer risk and reproductive problems, and can impair eye, liver, kidney, and other body functions. Similar problems can result from exposure to water near industrial plants or urban areas.