Purpose of the study: This article is a brief history of development of water sanitation systems in European countries. One of the aims is educating people about importance of water treatment in today’s world. 
 Methodology: Bellow article briefly discuss some history of drinking water supply and municipal wastewater sanitation, i.e., construction of historical water engineering system like water wells, first flush toilets, indoor plumbing and simple pressurized showers, sewage farms and irrigation, in China, ancient Greece, Roman Empire, Asia minor, India, by Mayans in America and in Australia.
 Main Findings: By the 1840s the luxury of indoor plumbing, which mixes human waste with water and flushes it away, eliminated the need for cesspools. As Britain was the first country to industrialize, it was also the first to experience the consequences of major urbanization and outbreaks of diseases like typhoid and cholera from contaminated water and was the first to construct a modern sewerage system. Most cities in the Western world added more expensive systems for sewage treatment in the early 20th century, after scientists at the University of Manchester Ardern and Lockett discovered the sewage treatment process of activated sludge in 1912.
 Implications of the study: More than 100 years have been passed since the activated sludge process was explored, since the time when the mankind started to realize how important is the water sanitation in diseases prevention. However, the water treatment technology is permanently improving and enriched with new innovative solutions, the basic principle from the year 1912 i.e., activated sludge process remains as the main process of all conventional wastewater treatment plants.