The City of Prague regularly monitors the quality of its environment. It produces an annual publication, whose objective is to provide comprehensive information on the state of the environment in the city of Prague. Among other issues, you can find information about the quality of water and air in Prague.

Water is one of the most precious natural sources. Any living creature, human beings included, and any plant would not be able to exist without it. Quality of water is, on one hand, influenced by social and ecological behaviour of humans, and, on the other hand, by the advancement in the technology by which we can maintain its required quality.

A casual consumer knows only tap water, water packaged in plastic bottles, or the water in natural resources, such as ponds, streams, rivers, and chemically treated water in swimming pools.

Let water be clean

An annual monitoring and assessment program is undertaken in order to maintain the quality of water. If necessary, measures are taken to improve the situation and reach the required standards. The evaluation of water quality is based on the Czech Standard. The standard is focused on a uniform determination of quality classes of flowing surface water – the classification, which serves as a benchmark of water quality at various locations and over various time scales. Surface water is classified into five classes based on quality: number one means unpolluted water, number two slightly polluted water, number three is polluted water, number four heavily polluted water and five very heavily polluted water.

As stated above, the quality of surface water is classified into five classes. Water quality is classified on the basis of checking results acquired over a longer continuous periods. According to the 2006 Yearbook, in 2005 there were in total 333 hydrometric profiles. In Prague and its vicinity four profiles were monitored on the Vltava and Berounka rivers. According to the Czech Standard, the classification of chlorophyll was the worst evaluated indicator of all the profiles.

The Vltava River – Vrané nad Vltavou was the best evaluated profile because more than half the 38 indicators measured attained Class I. Similar classification held true at Vltava – Podolí, followed by Vltava – Libčice and last one is Berounka – Lahovice.

Drinking water mainly from two sources

As opposed to surface water, drinking water has to be treated. The Káraný Drinking Water Treatment Plant and the Drinking Water Treatment Želivka are used in Prague for that purpose. The third water treatment plant is in Podolí, but is used minimally as the plant serves mainly as a reserve supply. The maximum capacity of the Kárané Drinking Water Treatment Plant is 1,900 litres per second. The Káraný plant is the only one of three water treatment plants serving Prague, of which a portion of water comes from groundwater sources. Its other source of water is surface water from the Jizera River.

The Drinking Water Treatment Plant Želivka is the most modern drinking water source for Prague and has the largest capacity as well. Its maximum output is about 7,000 litres per second. This water treatment plant water source is raw water from the Želivka River accumulated in the Švihov Water Reservoir.

In 2005, the steel-made mains supply pipe, which delivers water from the Káraný Water Treatment Plant to the water reservoir Ládví, was flushed clean. The flushing removed 1,335 insoluble particles from the supply mains. The flushing lasted for 15 hours, and in total 68 thousand cubic metres of water was discharged into the Labe River.

Water quality is regularly monitored by the Public Health Authority of the City of Prague. In 2005 there weren’t any significant deviations in water quality of samples monitored by this body.