Security measures in the water supply operations of a large city

The waterworks of the Hungarian capital, Budapest, is one of the largest water supply establishments in Europe. Besides the two million inhabitants of the capital and the 40 % of Hungarian industry located in the city, 12 suburban settlements and a regional waterworks are within its scope. Water shortage is unknown in Budapest. Three main areas of improvement are suggested with respect to the water supply system: increasing the economical efficiency of operation, at least preserving and if possible improving water quality, increasing the security of water supply. While the first two trends are unambiguous and accepted by all, there are different opinions about security. Security may concern the whole water supply system as well as a single part of the system i. e. a given water outflow.