The persistently low water level of the Danube is no longer merely an unusual summer sight. Passenger services and international river cruises are already being disrupted, while the prolonged drought is also raising concerns about the resilience of Budapest’s drinking water system. Beyond the capital, the ecological consequences are becoming increasingly severe as lakes, streams and rivers across Hungary continue to shrink.

After weeks of heat and limited rainfall, the Danube has fallen to exceptionally low levels across several countries in Central and Eastern Europe. In Budapest, the river recently approached the historic minimum registered in 2018, exposing sandbanks, rocks and sections of the riverbed normally hidden beneath the water.

According to the latest data published by Hungary’s Hydrological Information Service, the Danube stood at 70 centimetres in Budapest on the morning of 20 July. The forecast indicated that the level could fall again to approximately 55 centimetres by 26 July. The figure does not represent the actual depth of the river: it is measured against a fixed reference point on the water gauge.

The situation is even more serious further downstream. Portfolio reported that the Danube’s flow rate at its entry point into Romania fell to only 1,700 cubic metres per second over the weekend. The usual July average is approximately 4,700 cubic metres per second.

Romanian authorities introduced restrictions on agricultural water use in the country’s south-east and regulated releases from reservoirs to preserve the minimum water level required to cool the two reactors operated by state-owned nuclear energy company Nuclearelectrica. Ferries were suspended along parts of the Romanian–Bulgarian border, while grain barges were forced to wait because of exposed sandbanks and insufficient navigable depth.

Danube tourism is already feeling the impact

The consequences are particularly visible in river tourism. According to reports by Portfolio and industry publication Turizmus.com, several international hotel ships have been unable to continue their journeys from Budapest and Mohács, while others have remained in ports waiting for conditions to improve.

July bookings reportedly declined by 18 percent, and several sightseeing services north of Budapest had to be suspended. International operator Avalon Waterways was also forced to cancel some Danube and Rhine cruises because of unfavourable water conditions.

MAHART-PassNave has introduced temporary timetable changes. According to the company’s official passenger information, vessels operating on the Budapest–Szentendre–Visegrád route are unable to stop at Szentendre and Leányfalu because of the low water level. Some Budapest–Szentendre departures have also been reduced.

The international river-cruise segment is economically important for Hungary. MAHART-PassNave CEO László Somodi told Reuters that international river vessels carry approximately 600,000 passengers annually and have become the most valuable part of the Hungarian passenger-shipping industry.

Why it matters

River cruises connect Budapest with destinations including Vienna, Bratislava, Passau and the Lower Danube. When vessels cannot reach Budapest or passengers must be transferred by bus, the disruption affects far more than shipping companies.

Hotels, restaurants, guides, coach operators, ports and tourist attractions all depend on the spending generated by cruise passengers. Repeated cancellations could also damage Budapest’s position as one of the principal destinations on European river-cruise itineraries.

The problem is not confined to international hotel ships. Sightseeing cruises are an essential part of Budapest’s tourism offer, while scheduled boats provide an important seasonal connection between the capital, Szentendre, Visegrád and other settlements in the Danube Bend.

Could Budapest’s drinking water supply be affected?

Budapest does not simply pump untreated water directly from the Danube. Its drinking water comes predominantly from bank-filtered wells located mainly on Szentendre Island and Csepel Island.

River water passes naturally through several metres of gravel and sand beneath and beside the riverbed. This geological layer acts as a natural filter before the water reaches horizontal, tubular and radial collector wells.

According to the Fővárosi Vízművek 2025 business report, Budapest’s drinking water supply relies entirely on these types of bank-filtered wells. The system includes 756 production wells with a nominal capacity of 905,000 cubic metres per day, as well as 78 drinking-water reservoirs capable of storing a combined 331,000 cubic metres.

The system’s operation is closely connected to the Danube’s water level. Under normal conditions, the river creates sufficient hydraulic pressure for water to pass through the gravel layer towards the wells. When the river falls substantially, this pressure decreases.

As a result, the yield of higher-positioned collector arms can decline. In an extreme and prolonged low-water period, some of them may cease producing water temporarily. This does not automatically mean that Budapest will run out of drinking water, as the network contains hundreds of wells, substantial storage capacity and considerable production reserves. However, the lower the river falls and the longer the situation lasts, the greater the operational pressure on the system becomes.

The distinction is important: there is currently no indication of an imminent citywide drinking-water outage in Budapest. In late June, Fővárosi Vízművek told Mfor that it did not expect water shortages, pressure losses or service interruptions within its own service area.

Nevertheless, prolonged drought, exceptionally high consumption and declining well yields could reduce the system’s safety margin, particularly if several adverse factors occur simultaneously.

Why it matters

More than two million people depend directly or indirectly on the drinking-water bases around Szentendre Island and Csepel Island. The wells and their protected areas are therefore officially classified as critical national infrastructure.

The immediate question is not whether Budapest’s taps will suddenly run dry, but how resilient the system remains if exceptionally low Danube levels become more frequent, last longer and coincide with summer consumption peaks.

Water shortages recorded in the wider Budapest agglomeration show how quickly local networks can come under pressure. In late June, temporary shortages were reported in parts of Solymár, Üröm and Pomáz, while Szada was left without normal drinking-water service for approximately two days after its network became overloaded. These incidents were primarily linked to exceptionally high demand and limited distribution capacity, rather than a failure of Budapest’s water base, but they demonstrate the vulnerability of suburban systems during prolonged heatwaves.

The Dráva is also approaching a historic low

The Danube is not Hungary’s only major river affected by the drought. According to a separate SONLINE report, the Dráva has fallen close to its lowest level ever recorded on both the Hungarian and Croatian sections.

At Barcs, the water gauge fell to minus 164 centimetres, only nine centimetres above the historic minimum. The flow rate was measured at approximately 191 cubic metres per second. The river became so shallow beneath the bridge at Barcs that exposed sections could be crossed on foot.

A second-degree water-shortage preparedness level was introduced along the Dráva. Water-management specialists are operating the Ős-Dráva ecological water-replenishment system continuously to retain water in channels and reservoirs and protect the surrounding landscape.

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Lakes, streams and wetlands are disappearing

The wider ecological picture is equally worrying. Smaller streams and ponds have dried up in several parts of Hungary, while the water level of Lake Velence recently fell to a negative record of 41 centimetres, approximately one metre below its usual level.

Lake Balaton’s average water level was reported at 64 centimetres, forcing organisers to shorten the planned route of the Kékszalag sailing race. Low river levels also disconnect side branches and wetlands from the main channel, threatening fish spawning grounds, aquatic organisms and feeding areas used by waterbirds.

The damage extends beyond habitats immediately beside the water. Falling river levels can contribute to lower groundwater levels, drying soils, agricultural losses and the disappearance of vegetation that depends on wetlands and periodically flooded areas.

As we wrote earlier, Hungary’s Danube hits historic low, record-breaking water levels and water shortage raise alarm

From historic low water to another flood?

The current drought does not exclude the possibility of flooding later in the year. Budapest’s chief landscape architect, Sándor Bardóczi, warned that climate change is increasing the frequency of hydrological extremes.

As reported by Világgazdaság, Bardóczi argued that moisture accumulated in the atmosphere above the unusually warm Mediterranean could later produce heavy precipitation over the Alps. Depending on atmospheric conditions, this could affect the Danube catchment in autumn.

This should not be interpreted as a formal flood forecast. Bardóczi’s central warning was that a period of historic low water can now be followed relatively quickly by a major flood, making long-term water retention, the rehabilitation of side branches and climate-resilient river management increasingly important.

Hungary is therefore confronting two sides of the same problem: too little water for increasingly long periods, followed by the possibility of sudden and destructive excess. The disruption of tourism is already visible, while the potential consequences for drinking-water security, agriculture and natural ecosystems will depend on how long the present drought continues.

Before this happened: Hungary gripped by alarming drought as iconic lakes and rivers face unprecedented peril