Where does the water from our taps actually come from?

Trout check water quality for Prague

For a long time, the Vltava River and the waterworks in Podolí, founded in 1929, were sufficient to supply Prague with water. Even older is the water treatment plant in Káraný, which pumps groundwater. When Prague began to grow rapidly in the 1960s and large housing estates were built, the Želivka River emerged as a new suitable source of water. The large Švihov Dam was built near the village of Nesměřice and now supplies approximately 63% of Prague’s households. The rest of the water is supplied by the Káraný water treatment plant (about 25%) and the Podolí waterworks (approximately 12%). Most of Prague’s residents drink water from the Želivka, but in the northern part and centre of the city, it is mixed with water from Káraný, which is mainly pumped from a total of 680 wells located along the Jizera River. In addition to water from the river, which is artificially purified with sand along the way, several thousand-year-old artesian water from artificial wells is also used.

And do you know what is interesting? In the area of the Švihov reservoir, entry, fishing and swimming are prohibited, but at the Water House you can arrange a guided tour of the dam (and you can also see the unique flooded Borovský bridge). There is also something special in Káraný: water managers test the quality of water filtration here in a reservoir where a flock of rainbow trout lives. If even one fish were to be startled, the pumping of water would be stopped immediately.

Record-breaking water tunnel and sewer network

Treated water from the Švihov Dam travels to Prague through a 52-kilometre-long water tunnel. This tunnel, often called a tunnel feeder, is the sixth largest water tunnel in the world. The water travels through it mainly by gravity, so the journey takes about fifteen hours. However, the water does not flow directly into the city network, but first into Prague’s main water reservoir in Jesenice.

There are about seventy water reservoirs in Prague, supplying various parts of the city. The underground water supply system measures more than four thousand kilometres, and the sewage network for waste water is slightly shorter. Most of the polluted water goes to the central treatment plant on Císařský ostrov, but there are several dozen other treatment plants in the outskirts of Prague.

Where does drinking water for large cities come from?

The western Bohemian city of Plzeň, which has more than 170,000 inhabitants, has long drawn water from the Radbuza River. For more than 300 years, its water was the source for the fountains on Republic Square. Today, like Klatovy, Domažlice and their surroundings, Plzeň draws water mainly from the Úhlava River. The Nýrsko reservoir, built in the late 1960s after the flooding of the Úhlava Valley in what was then the Šumava Protected Landscape Area, is used to store water. Of all the reservoirs in the Berounka River basin, it has the cleanest water and is easy to treat for drinking.

A large part of southern Moravia, Brno and its surroundings are supplied with drinking water from the spring in Březová nad Svitavou and the Vír reservoir. The Boskovice reservoir, one of the last dams built in the Morava river basin, serves as a backup water source. This reservoir is used for water supply purposes and, during periods of drought, helps to increase low flows in Bělá and Svitava. Conversely, during floods, it is designed to retain up to ten thousand cubic metres of water.

Large towns below the Ore Mountains receive water from the Křímov and Fláje reservoirs. The Fláje dam itself is not intended for recreation, but at the Fláje Waterworks Tourist Information Centre, located directly on the dam, you can book a tour of the dam’s internal concrete structure and admire the technical perfection that holds back an enormous amount of water. The pillar dam is unique in the Czech Republic.

The Souš Dam in the Jizera Mountains also serves as a water source for the Jablonec and Tanvald regions. Nearby is its damaged twin, a broken dam.

Drinking water for the Ostrava region is mainly provided by the Šance Reservoir and the Kružberk Dam. The construction of a dam on the Moravice River was already being discussed at the beginning of the 20th century, when Austria-Hungary and Prussia were negotiating cooperation. Prussia wanted to improve the flow of the Oder River for navigation, while Austria-Hungary was looking for water for the Ostrava region. Construction of the Kružberk waterworks did not begin until after the Second World War, and it became the first dam in northern Moravia and Silesia.

The Římov reservoir, built between 1971 and 1978, serves as a source of drinking water for České Budějovice.

New dams in the Czech Republic

The dam in Nové Heřminovy has been under discussion for a hundred years. If built, it could help prevent devastating floods in the Opava and Ostrava regions in September 2024. After many delays, its construction is planned to begin in 2027. In addition to the Nové Heřminovy dam, many other reservoirs are planned in the Morava and Vltava river basins to serve both as flood protection and as sources of drinking water.

The Vlachovice water reservoir on the Vlára River, which will provide drinking water for most of the Zlín Region, is the furthest along in its preparation. Its capacity is to be one third larger than the Brno dam. It could be completed in 2033.

Another important waterworks for flood protection in the Přerov region is the Skalička side dry reservoir on the Bečva River. However, its construction may be delayed due to the necessary land purchases.

In the Rakovník area, which together with southern Moravia is one of the driest locations in the Czech Republic, two smaller reservoirs are planned, Senomaty on the Kolešovický stream and nearby Šanov on the Rakovnický stream. The planned Kryry reservoir in the Podbořany area should also mitigate the effects of drought in the region.

Facts and interesting information about water

• • Average water consumption in the Czech Republic is 90 to 100 litres per person per day.

• • Since 1989, water consumption has fallen by almost half. At that time, it was around 171 litres per person per day.

• • The Czech Republic has long had one of the lowest water consumption rates in Europe. For example, in Switzerland, the USA, Japan and the UK, residents consume almost 300 litres per day, in Italy 220 litres, in Portugal about 205 litres and in Spain 140 litres. At the opposite end of the scale are Slovakia (about 80 litres) and Estonia (88 litres).

• • Every year on 22 March, World Water Day is celebrated around the world. The lack of quality water resources has long been one of the most serious global problems. Despite the efforts of many organisations and associations, more than a billion people around the world do not have access to clean drinking water. Due to climate change, countries that previously had no problems with access to water are also expected to soon face a shortage of resources.

• • Although the human body is very adaptable, it cannot go without food or water for long. The ability to survive without water is much worse than without food; usually, human organs stop functioning after three days without drinking. Water hydrates, cleanses the body of harmful toxins and helps remove impurities from the liver and arteries.

• • Water reservoirs, which serve as drinking water supplies, have the status of protected water sources. Swimming is prohibited in these areas, and many of them are fenced off and monitored by CCTV systems.