Where does your drinking water come from in Hungary?

Is it  karst water from a limestone mountain? Or is it bank filtered water from a nearby river? Is it perhaps hidden deep under the ground?

The source of drinking water is called raw water. It can be groundwater, surface water or even rainwater. The source of water influences water quality, chemical composition, and physiological effect. Raw water requires water treatment technologies. For drinking water supply groundwater is preferred as it is less vulnerable and thus usually has better quality than surface water. As a result, groundwater needs less treatment which means fewer chemicals in it as well.

Since shallow groundwater can easily be contaminated by bacteria and nitrates due to agricultural landuse, it’s advisable to look for deeper aquifers. Water spends here a very long time, ca. 10.000 years or more. During that time water interacts with rocks which leads to high dissolved mineral content. It can be beneficent for human health (e.g. medicinal water), however  many natural contaminants can also enter the water, such as arsenic, iron or manganese. (You can read more information about groundwater pollution in a previous post on the blog.) These aquifers are often “polluted” by gases such as methane that makes production more complicated. In the case of deep groundwaters, we must also take into account that they can become significantly warm during their journey. Although thermal waters are excellent for spas and baths but usually unsuitable for drinking. In Hungary, 40% of the water supply is covered from deep aquifers.

Karst water in limestone and dolomite mountains is one of the best sources of drinking water. It has a low iron and organic matter content but it’s reach in dissolved calcium and magnesium. The two latter elements are favorable for human health, however, these can cause problems in the pipelines as hard water quickly forms limescale deposits. As a further problem, uncovered karsts are highly vulnerable aquifers which can risk water quality. Karst water gives 20% of water supply in Hungary.

Rapid contamination of karst springs during heavy rains

Source: https://mindentudas.videotorium.hu/hu/recordings/6748/talpunk-alatt-folyik-felszin-alatti-aramlasok-a-viz-korforgalmaban

You could hear about induced bank filtration from our previous posts, as it gives approximately 30% of Hungary’s water supply. This technology clears water naturally with the help of a biofilm layer during its flow from the river into the aquifer. Drinking water has a better quality this way than if we extract it directly from surface water.

In some cases, however, surface water abstraction is required. In this case, the increased content of organic and suspended matter must be taken into account. In addition, surface waters are characterized by a lower solute content, and impurities that can cause unpleasant taste and smell. As these waters are more exposed to pollution, more complex water treatment technologies are needed. We must protect our groundwater resources and have deliberate water management plans to preserve drinking water resources.

“Although not widely known, but in Hungary almost 95% of water consumption comes from groundwater. This is one of the reasons why it is worth learning more about these waters and related processes, as this way we can find out what gets into our glasses! Have a nice time on the blog” - Judit Mádl-Szőnyi, the scientific coordinator of ENeRAG project!