Extreme drought: 22 millimetres of rainfall were recorded in the Ruhr region in July

According to preliminary analyses by the Ruhrverband, just 22 millimetres of rainfall – 77 per cent less than usual – fell in the Ruhr catchment area in July 2026. This means that, even before the final data validation, it is already clear that it was one of the two driest – and probably even the driest – Julys since records began 100 years ago. A look at the preceding months further illustrates just how challenging the water management situation has been overall in 2026: since November 2025, the start of the current flow year, with the exception of the (average) month of February and the (very wet) month of May, all months have been drier than average – November, December and March by more than half, and July (see above) is expected to be by more than three-quarters.

Overall, there has been around 30 per cent less rainfall in the first nine months of the 2026 flow year than is usual for this period. To reach a figure close to the average annual rainfall, the remaining months up to the end of October would have to be very wet – though current forecasts for the coming weeks do not suggest this will be the case.

For the Ruhrverband’s reservoir system, the current situation means one thing above all: hard work. On all 31 days in July, it was necessary to release water from the reservoirs to maintain the statutory minimum flow at the Villigst gauge near Schwerte. On 18 of those days, the Ruhr would even have run completely dry at this gauge because the volumes withdrawn were higher than the flow would have been without the supplementary water from the reservoirs.

“These figures impressively illustrate that the importance of the reservoirs for the secure supply of drinking water to our region cannot be overstated,” emphasises Prof. Christoph Donner, Chairman of the Ruhrverband. “Due to climate change, dry spells such as those we are currently experiencing, as well as heavy rain, storms and floods, are becoming part of our new reality. Working in conjunction with renaturalised watercourses, unsealed land, ‘sponge cities’ and ‘sponge forests’, our reservoirs are vital multifunctional storage facilities – they are already so today, and will be even more so in the future. Keeping water where it is needed and further developing natural and artificial storage capacities in a targeted manner will therefore be our task in water management.”

Looking ahead to the coming months, Christoph Donner has some reassuring news: “The water level in our reservoir system is currently around 80 per cent of full capacity, which corresponds to a total volume of around 380 million cubic metres. This will enable us to ensure the water supply, even if conditions remain dry over the coming weeks and months.” However, the Chairman of the Executive Board went on to say that, in July alone, the Ruhrverband had to release 31 million cubic metres of water from its reservoirs in order to maintain the minimum flow in the Ruhr. “Water cannot be taken for granted,” is therefore Christoph Donner’s urgent appeal. “It is a precious resource that we must treat with care. That is why we at the Ruhrverband support the ban on water abstraction from the Ruhr and Lenne rivers imposed by the Arnsberg District Government. In this way, each and every one of us can help to conserve our water reserves.” 

Background: Discharge years (also known as hydrological years or water management years) differ from calendar years so that the annual balance can also account for precipitation in the form of snow and ice that falls as early as early winter. This is because they only contribute to runoff as meltwater in the following calendar year. In Germany, a DIN standard defines the discharge year as running from 1 November to 31 October, as experience shows that water reserves are at their lowest at the end of October.