Signs of a Water Crisis? The Environmental Impact of Mega Data Center Construction

Whose Water Supports the Convenience of AI? The Question Raised by Germany's Massive Data Centers

Asking AI questions on a smartphone. Playing videos. Saving work files to the cloud.

These actions, which seem to be completed within the screen, are actually supported by data centers located somewhere on the land. There, servers are lined up, electricity flows, and equipment operates to dissipate the heat generated.

The "water" used for cooling has become a major point of contention in Germany.

On November 6, 2026, German public broadcaster ZDF reported that the construction of massive data centers driven by the AI boom could strain regional water supplies. This was based on a short-term study compiled by Öko-Institut, commissioned by the environmental group Greenpeace.

When increasing convenient digital services, how will the foundational water be secured? And who will be responsible for balancing it with living, agriculture, and the natural environment?

This is not just a matter concerning the construction of facilities in distant countries. It is an unavoidable question when considering the future of digital infrastructure in Japan.

13 Billion Liters Annually, But Not "Water Used Solely by AI"

According to ZDF, the study estimates that data centers in Germany will consume about 13 billion liters of water for cooling in 2025. This could increase to about 27 billion liters annually by 2030.

The 27 billion liters, as converted in the study, corresponds to the annual water demand of a city with about 580,000 people. The drinking water demand here does not only mean the water people drink from a glass. It needs to be understood as the scale of water supply supporting life.

Moreover, this figure does not indicate water consumption solely by facilities dedicated to generative AI. It includes estimates for existing data centers supporting the cloud and other services, and it is inaccurate to rephrase it as "AI drank 13 billion liters annually."

The future figure of 27 billion liters also comes with conditions. It is an estimate based on assumptions such as the expansion of facilities and the lack of progress in water-saving measures, and it is neither a measured value for 2030 nor a guaranteed figure.

The larger the numbers, the more one might be tempted to judge by headlines alone. However, understanding what is being targeted and under what conditions the numbers were calculated is the starting point of this issue.

The Issue Is "Where the Water Is Used," Not "How Many Liters Nationwide"

When considering the impact on water, there are things that cannot be seen by just looking at the national total.

Even with the same amount of water, the burden on the region differs if it is used in a place with ample supply versus a place where groundwater or river water levels are tight. Even if the annual average is small, if water demand is concentrated in specific seasons, it is necessary to check the supply capacity during that period.

In the estimate introduced by ZDF, for a single 100-megawatt data center, water demand is expected to range from 200 million to 930 million liters annually, depending on the cooling method. On the higher side, this is equivalent to the annual water demand of a town with about 20,000 people.

This figure does not mean that all 100-megawatt facilities consume the same amount. Rather, it shows that water demand can vary greatly depending on the choice of equipment, even at the same scale.

Residents want to know more than just the national share.

Do they use the same water source as us? How will operations be adjusted in case of drought? If water infrastructure needs to be enhanced, who will bear the cost?

Even if the national share is small, it can become a significant user in specific regions. Ignoring this difference in scale can lead to miscommunication between businesses and residents.

The Industry Says "Many Facilities Use Very Little Water"

On the other hand, it's necessary to also consider the explanations from the data center industry.

The German digital industry association Bitkom stated on November 3, 2026, that 65% of domestic facilities consume less than 0.1 liters of water per kilowatt-hour of IT power usage. They also emphasized improvements in water use efficiency, suggesting that it is not appropriate to view all facilities as massive water consumers.

In contrast, the analysis by Öko-Institut introduced by ZDF calculated a weighted average of 0.67 liters per kilowatt-hour, excluding inappropriate data.

It is important to note here that "what percentage of facilities are low consumption" and "what is the average when weighted overall" are different questions.

For example, even if there are many small-scale, water-saving facilities, if large-scale facilities use a lot of water, the overall water demand can increase. This is an explanation of the aggregation mechanism, and it does not solely explain the numerical difference in this case. Comparisons require confirmation of the target facilities, the scope of public data, and how the average is taken.

"Many facilities use little" and "it can be a significant burden in some regions" can coexist. A single number cannot determine the safety of a construction site.

Just Hearing "Water Cooling" Doesn't Reveal Water Consumption

Another important aspect in understanding this issue is the difference in cooling methods.

Circulating water to transport heat and consuming that water through evaporation are not the same. Even if a liquid is circulated within the equipment, the design at the stage of releasing heat outside affects water consumption.

Evaporative cooling utilizes the property of water absorbing heat when it evaporates. While evaporated water does not disappear from the earth, it does not immediately become usable as domestic water in the original region. This difference is important when considering regional water supply.

On the other hand, the study points out that direct cooling water consumption can be reduced by choosing options like dry cooling.

Therefore, it is difficult to judge based solely on the name of the method, such as "water cooling is bad" or "circulation is fine." What is needed is an explanation of where the facility as a whole draws water from, where it evaporates, and how much is replenished.

Advancing the question "Do you use water for cooling?" to "How much new water needs to be replenished from the region?" makes the discussion more concrete.

"Energy Savings Require Large Amounts of Water" Is Not Always True

The environmental performance of data centers cannot be evaluated solely by the efficiency of electricity or water.

According to ZDF, the current study did not confirm a statistical relationship that facilities with high power efficiency necessarily use more water. There are facilities that achieve both high energy efficiency and low direct water consumption.

However, the lack of a clear correlation across facilities does not prove that there is no trade-off between electricity and water in individual equipment.

The suitable cooling method changes depending on the climate and equipment conditions of the construction site. A design that reduces water in one facility may not be achievable at the same cost or power usage in another.

The takeaway here is that it is not a matter of solving the issue by choosing one universal cooling method.

Businesses need to present multiple design proposals and consider water, electricity, cost, and regional supply capacity. They then need to explain why that method was chosen.

The Biggest Barrier Is the Lack of Data for Decision-Making

In discussions about environmental impact, the size of numbers often draws attention. However, equally serious in this case is the weakness of the system for understanding those numbers.

ZDF reports that less than half of the approximately 1,200 businesses required to report submitted data, and only 139 reports were usable for analysis.

The summary of the government response published by the German Bundestag on October 20, 2026, also indicated that not all target facilities have submitted reports, showing limitations in understanding.

In this state, even if residents are concerned or businesses explain that the problem is small, there is a lack of shared judgment material between the two.

Moreover, recipients of estimates should be cautious. National estimates derived from limited data are uncertain. However, this does not conclude that the burden is small.

What is needed is to acknowledge the uncertainty and enhance actual measurements and disclosure. If annual consumption per facility, seasonal variations, water sources, and responses during droughts can be confirmed, abstract pros and cons can be advanced to discussions on specific measures.

On Social Media, the Focus Is on "Responsibility to Explain" as Well as "Amount Used"

Related reports on water and electricity consumption of data centers are being discussed on public social media.

However, what is introduced here is not a direct comment on the current ZDF article. It is a reaction found on Reddit's "r/europe" regarding another report dealing with information disclosure of European data centers. The content of the post is an example of opinion and does not represent the overall public opinion in Europe.

In that thread, there was an opinion questioning whether the amount could be understood through power companies if businesses do not show numbers. There were also voices questioning what consequences accompany failure to report or providing inaccurate data.

What can be read from this is a problem awareness not only of concerns about using large amounts of water but also of wanting "large companies to fulfill their responsibility to explain."

On the other hand, there was also a counterargument that public disclosure and reporting to the administration should be distinguished. It was pointed out that companies not publicly disclosing information to everyone is not the same as supervisory agencies not having the information.

This distinction is important. Just because something is not publicly disclosed does not mean it can be definitively labeled as a violation or concealment.

Nevertheless, the question remains of how to improve the situation where residents cannot obtain judgment materials for facilities affecting regional water resources. Discussions on social media indicate that environmental issues are also issues of trust in companies and administrations.

What Japan Should Consider Are the Specific Conditions Before Attraction

The implication for Japan is not to directly apply Germany's estimates domestically. Differences in climate, water sources, equipment, and land use will change how the burden manifests.

Rather, what is instructive is what should be confirmed at the stage of considering the attraction and construction of facilities.

First, clarify the water source. Depending on whether the supply is from tap water, groundwater, or industrial water, the parties to be checked for impact will change.

Next, indicate not only the annual usage during normal times but also the maximum demand during hot periods and the operational policy during droughts. It is necessary to prepare an answer in advance to the question of how the facility will respond in situations where residents are asked to conserve water.

Finally, ensure that the performance after operation can be confirmed. If there is a gap between the explanation at the planning stage and the actual consumption, it should be determined who will verify and how improvements will be made.

These are not conditions for uniformly rejecting data centers. They are conditions for coexisting with regional life and operating for the long term.

Digital service users and residents near facilities do not live in separate worlds. The same person can be on the side enjoying convenience and on the side worrying about water supply.

Supporting the Future of Digital Is an Explanation That the Community Can Agree With

In news competing over AI performance, processing power and investment amounts tend to take center stage. However, the places where these facilities operate have water sources, lives, and other industries.

The current study does not prove that all data centers cause water shortages. What is indicated is that as facilities become larger, if cooling methods, location, and information disclosure are insufficient, the burden and conflict in the region may increase.

Turning the explanation of "being environmentally conscious" into numbers that residents can verify. Showing how water is used beyond the words "energy-saving."

To continue using convenient services with peace of mind, such diligent explanations on the side of invisible facilities are indispensable.

Clouds do not float in the sky. They are built on the same land as us and operate using the same regional resources.

Sources and References

1. ZDFheute (November 6, 2026)
   Estimates of cooling water, differences in views with the industry, concerns about regional water supply, and information shortages.
   https://www.zdfheute.de/wirtschaft/wasser-versorgung-rechenzentrum-folgen-greenpeace-studie-100.html

2. Öko-Institut/Greenpeace "Water Consumption of Data Centers in Germany"
   Original survey. Referenced to confirm assumptions of future estimates, cooling methods, and the meaning of regional water consumption.greenpeace.de
   https://www.greenpeace.de/publikationen/Kurzstudie_Wasserverbrauch_deutsche_Rechenzentren.pdf

3. Bitkom (November 3, 2026)
   Industry association announcement. Explanation that 65% of facilities have low direct water consumption, and water use efficiency indicators.Bitkom e. V.
   https://www.bitkom.org/Presse/Presseinformation/KI-Boom-treibt-Rechenzentren-in-Deutschland

4. German Bundestag (October 20, 2026)
   Summary of government response. Limitations in reporting and understanding data center water consumption.Deutscher Bundestag
   https://www.bundestag.de/presse/hib/kurzmeldungen-1225774

5. Reddit "r/europe" Public Thread##HTML_TAG