What are we drinking? We tested bottled water from taps in Prague and Karlovy Vary
We drink about three liters a day, we don’t survive without it for more than three days, and its molecule consists of two hydrogen atoms and one oxygen atom. Everyone knows all about water. But do you also know what substances in the water we drink should have been and in what amounts? And what should definitely not be in it?
As part of the summer edition of the Forbes Next special, the main topic of which is water, we had five water samples tested in the VZlab specialized laboratory in Prague in order to answer these questions.
We analyzed two water samples from a common water supply system in Prague-Libno and Karlovy Vary, bottled water was represented by the Dobrá voda and Saguaro brands, and for comparison we also had water taken from the Vltava tested after the river flowed through the whole of Prague.
You can see detailed results in the gallery. These are the five most important findings from the analyzes.
The tap water is of high quality
All samples of tap and bottled water for a few details almost without the remaining elements of the standard for drinking water, which stipulates the decree. In the case of tap water, this has confirmed that, in general, drinking water treatment is at an absolutely top level – while in some European countries drinking tap water is a risk, in the Czech Republic you can rest easy.
The water in Prague and Karlovy Vary did not meet the standard only with a lower magnesium content, the Karlovy Vary sample with an even lower hardness. In contrast, traces of heavy metals, toxic substances or bacteria were not detected. If you still don’t like the water from your tap, the old wiring in your house is most often to blame.
Bottled water does not make sense for normal use
We assumed that the Saguaro bottled water, whose two-liter package is sold by the Lidl chain for 4.50 crowns, will be the worst in the test. The water for which the manufacturer does not state the source, but paradoxically the only one in our test, met the required standards to the fullest. A small amount of trihalomethane, which is a product of disinfection (lay chlorination), but indicates that the water is post-treated. Unlike Dobrá voda, which, however, contains less magnesium and calcium and is also significantly softer than stipulated by the decree.
In both cases, however, you carry water in PET bottles that is almost chemically identical (especially for the Saguar) to the one that flows from the tap. In addition, drinking bottled water is treacherous in that if you always let the tap water run fresh, bacteria will certainly start to multiply in the open PET water bottle, even in the fridge, and then drink.
Dobrá voda won the infants
If you have an infant at home who is less than three months old, you should pay attention to the amount of nitrates by the water. While the body of an adult can deal with them without any problems (the standard stipulates a maximum of 50 mg per liter), they can be toxic for a small child. Baby water should thus have a maximum of 10 mg / l nitrates, which is met by Dobrá voda (0.56 mg / l) and also water in Karlovy Vary (5.4 mg / l). On the contrary, most of them are in Prague water – 16.2 mg / l.
Pay attention to the hardness of the water
The hardness of water is also a value that is worth monitoring. According to the decree, it should be in the range of 2 to 3.5 mmol / l, which is met only by water in Prague and bottled water Saguaro. In the long run, too soft and too hard water harms the human body. In the first case, it will start to lack minerals (eg Good water is extremely soft at 0.49 mmol / l), otherwise it will have an excess. For the same reason, you should also pay attention to mineral waters. Excessive consumption can cause hypertension, kidney stones or higher cholesterol.
The Vltava is quite clean
The water from the Vltava, which we took in Holešovice, ie due to the direction of the current at the end of Prague, also turned out surprisingly well in the test. If it was measured according to the Ordinance on Drinking Water, there is less magnesium and calcium in it, on the contrary, more iron and manganese, but from a chemical point of view they do not differ from drinking water (there are no toxic substances). As expected, however, it is not suitable from a bacteriological point of view, you will find traces of fecal contamination (intestinal enterococci), which are common in lowland streams. A slight turbidity is also appropriate. So you can’t drink such water, but swimming in it will definitely not hurt you in any way.