Data Center Water Usage: A Comprehensive Guide

Data centers are significant consumers of natural resources, and while carbon emissions and electricity consumption often capture most attention, water usage is also gaining increased recognition. Water is essential in data center cooling systems to control the heat produced by these massive facilities, ensuring their internal servers run uninterrupted 24 hours a day, 7 days a week.

Data centers use large amounts of water for their cooling systems, which include cooling towers, chillers, pumps, pipes, heat exchangers, condensers, and computer room air handler (CRAH) units. Additionally, data centers need water for their humidification systems and facility maintenance.

Globally, data centers are located in all different types of countries and climates, including many data center facilities in water-stressed regions prone to droughts. According to the United Nations, by 2025, 50% of the world’s population is projected to live in water-stressed areas, making data center water usage a key environmental area to prioritize change.

Dgtl Infra provides a comprehensive analysis of data center water usage, detailing their annual consumption and specific water-related metrics. Furthermore, we offer a thorough examination of water sustainability initiatives undertaken by leading global data center operators, including Amazon Web Services (AWS), Microsoft, Google, Facebook (now Meta Platforms), and Apple.

Why Do Data Centers Use Water?

Data centers use significant amounts of water on-site primarily for their cooling system, which comprises cooling towers, chillers, pumps, pipes, heat exchangers, condensers, and computer room air handler (CRAH) units. In addition, some computer room air conditioning (CRAC) units can be water-cooled, especially in larger installations.

An illustration below depicts a typical data center layout, highlighting key components of the cooling system:

Beyond cooling, data centers use water for other purposes, though to a smaller extent. These include humidity control, fire suppression systems like wet pipe sprinklers, and general facility maintenance.

It is important to note that data centers also indirectly consume substantial water off-site. This occurs primarily at power generation plants that supply electricity to the data centers. However, Dgtl Infra’s analysis focuses solely on the on-site water usage, particularly for cooling and humidification systems in data centers.

Cooling System

Data centers traditionally use two types of cooling methods: water cooling and air cooling. Water cooling uses water in different forms, such as in chilled water systems or cooling towers, to absorb and remove heat from servers, storage systems, networking equipment, and power supplies.

The most common type of water-based cooling in data centers is the chilled water system. In this system, water is initially cooled in a central chiller, and then it circulates through cooling coils. These coils absorb heat from the air inside the data center. The system then expels the absorbed heat into the outside environment via a cooling tower. In the cooling tower, the now-heated water interacts with the outside air, allowing heat to escape before the water cycles back into the system for re-cooling.

While water cooling is efficient and particularly effective in managing high heat densities, making it a preferred option for large ‘hyperscale’ data centers, it raises environmental concerns. One of the primary issues is the significant water usage, which is a pressing concern, especially in regions facing water scarcity.

READ MORE: Data Center Cooling – A Comprehensive Guide

Humidification System

Data centers utilize water in their humidification systems to maintain optimal humidity levels, especially during winter. This practice is crucial for preventing the build-up of static electricity and ensuring the longevity and reliability of sensitive IT equipment.

Water is introduced into the air through various humidification methods, such as evaporative cooling or mist systems, to maintain a specific humidity range of 40% to 60% relative humidity. This process helps to create a stable environment in computer rooms, reducing the risk of damage to servers and IT hardware due to dry conditions or electrostatic discharge (ESD).

How Much Water Does a Data Center Use?

Data center water consumption varies based on factors such as facility size, cooling system type, and external temperature and humidity. Typically, these facilities consume less water in winter and more in summer. This is because higher outdoor temperatures increase the energy needed for cooling systems, which in turn requires more water to reduce the data center’s internal air temperature to optimal levels.

The water consumption of data centers can be illustrated with two examples: i) hyperscale data centers and ii) wholesale and retail data centers. In both cases, a single data center uses several million gallons/liters of water each year.

Hyperscale Data Centers – Water Usage

Hyperscale data centers, which are large facilities designed for cloud service providers (CSPs) and major internet companies, consume significant amounts of water. These facilities typically have power capacities between 10 to 100 megawatts and can span millions of square feet. As a result, their water usage is very high.

For example, Google’s hyperscale data centers, which support its cloud regions and core products like Gmail, Google Drive, and YouTube, used an average of 550,000 gallons (2.1 million liters) of water daily over the past year. This amount totals to approximately 200 million gallons (760 million liters) annually.

Wholesale and Retail Data Centers – Water Usage

In contrast, smaller data centers in Prince William County, part of the Northern Virginia data center market, showed lower water consumption levels. These facilities, generally ranging from 100,000 to 250,000 square feet, recorded an average daily water usage of about 18,000 gallons (68,100 liters), or 6.57 million gallons (24.9 million liters) annually.

The highest recorded daily water usage for a single data center in this area reached around 88,000 gallons (333,100 liters), which equates to about 32.1 million gallons (121.6 million liters) annually. These water usage figures are markedly lower than those of Google’s larger hyperscale data centers.

Where Do Data Centers Get their Water?

Data centers primarily get their water from municipal or regional water utility companies. This water is essential for the data center’s cooling and humidification systems.

For cooling, data centers mainly use potable water, which is suitable for drinking, provided by these utilities. Additionally, they occasionally use non-potable water, such as greywater (treated sewage) or recycled water. For instance, Google employs some reclaimed or non-potable water in over 25% of its data center campuses.

On average, alternative water sources contribute less than 5% of a data center’s total water supply. These sources include on-site groundwater, surface water, seawater, produced water (a byproduct of oil and gas extraction), and rainwater harvesting systems.

What Happens to Water Used to Cool Data Centers?

Once water is used to cool data centers, several outcomes are possible, depending on the cooling system design and environmental regulations:

1. Recirculation and Reuse: In many cooling systems, the water is recirculated. After absorbing heat from the data center, the warm water is cooled down again through various methods (like cooling towers or heat exchangers) and then reused
2. Discharge: Some cooling systems discharge used water as industrial wastewater, usually into a nearby wastewater treatment facility or a body of water like a river, lake, or ocean. This discharge, however, is typically regulated to ensure the temperature of the discharged water is not too high to negatively impact the local ecosystem
3. Evaporative Cooling: In systems like cooling towers, a portion of the water evaporates and is consumed while cooling the remaining water. This evaporative process is efficient for cooling but results in water loss

Effective treatment of water, whether conducted on-site or at an external wastewater treatment plant, enables its repeated use in the cooling system of a data center. This recycling is contingent on the water meeting certain quality standards, such as acceptable hardness levels.

Do Data Centers Reuse Water?

Data centers often reuse water by circulating the same water multiple times through their cooling systems. Google reports that this method can save up to 50% of water compared to traditional ‘once-through’ cooling systems.

Another method involves the use of stormwater retention ponds at data centers. These ponds collect rainwater, which is then treated and repurposed for various non-potable functions within the facility, including cooling systems.

However, there is a limit to how long water can be reused in these systems. Replacement becomes necessary either due to the risk of scale formation or when the water’s conductivity reaches excessively high levels. Scale-forming minerals such as calcium, magnesium, and silica accumulate in the water, becoming more concentrated with each cycle of evaporative cooling. Eventually, this necessitates the replacement of the water.

In the end, ‘spent’ water used for cooling in data centers can be treated and repurposed for other uses, such as irrigation or flushing toilets.

Water Usage Effectiveness (WUE)

Water Usage Effectiveness (WUE) is a critical metric for assessing the water efficiency of data centers. It specifically measures the amount of water used to cool the facility’s equipment.

WUE is calculated as the ratio of the data center’s annual water use (in liters) to the energy consumed by its IT computing equipment, measured in kilowatt hours (kWh). Thus, WUE is expressed in liters per kilowatt-hour (L/kWh). According to Meta Platforms (formerly Facebook), the industry’s average WUE was most recently 1.80 L/kWh, indicating that 1.80 liters of water were used for every kilowatt-hour of electricity consumed.

Data Center Water Usage of Major Companies

Cloud Service Providers (CSPs) and major internet companies, often referred to as hyperscalers, have recently published data on their data center water usage. Key hyperscalers, such as Amazon Web Services (AWS), Microsoft, Google, and Meta Platforms (formerly Facebook), have pledged to be water positive by 2030.

Amazon Web Services (AWS) – Data Center Water Usage

Amazon Web Services (AWS) has committed to be water positive by 2030, returning more water to communities and the environment than it uses in its direct operations. Specifically, AWS’ water positive commitment applies to AWS leased, owned, and colocation data centers, as well as AWS offices. The company’s data center commitments form the basis of its water use strategy for each operational AWS Region.

Presently, AWS uses recycled water for cooling in 20 data centers around the world, including those shown in the map below, namely Virginia (United States), California (United States), Oregon (United States), United Kingdom, Spain, Brazil, South Africa, India, Indonesia, Singapore, and Australia.

READ MORE: Amazon Web Services (AWS) Data Center Locations

Water Positive Calculation

AWS calculates its progress toward its water positive goal as follows:

Water efficiency improvements by AWS will be reflected in a declining volume of incoming water. If the percentage is under 100%, that means AWS has not met its water positive goal. Whereas if the percentage is over 100%, that means AWS is returning more water to the community than it is using – meaning AWS is water positive.

AWS’ four key strategies to become water positive are:

1. Improving water use efficiency across its operations
2. Using sustainable water sources (e.g., recycled water)
3. Returning water for community reuse
4. Supporting water replenishment projects for communities and the environment

Water Usage Effectiveness (WUE)

AWS’ global Water Usage Effectiveness (WUE) metric averaged 0.19 liters of water per kilowatt-hour (L/kWh) of electricity used across its data centers worldwide. This represents a 24% improvement from the previous year’s 0.25 L/kWh.

Annually, AWS reports on its WUE metric, along with new water reuse and recycling efforts, activities aimed at reducing water consumption in its facilities, and water replenishment projects.

Amazon aims to replenish 3.9 billion liters of water annually through its water restoration projects. Some of these projects are already in operation, returning water to the environment, while others are scheduled to commence shortly.

Cooling System Strategies

Amazon Web Services (AWS) employs two main cooling system strategies: direct evaporative cooling and free-air cooling.

Direct Evaporative Cooling System

AWS’ preferred cooling strategy for its data centers is known as direct evaporative cooling. In this system, hot air is pulled from outside and pushed through water-soaked cooling pads. The water evaporates, reducing the air’s temperature, and the cool air is then sent into the server rooms.

Free-Air Cooling System

AWS has also implemented a free-air cooling system to minimize water usage in its cooling processes. This system is operational at certain AWS data centers, where sensors are installed to monitor weather conditions, including temperature and humidity. When these conditions fall within a safe operating range, AWS deactivates its evaporative cooling system and, instead, it draws cool external air directly into the server rooms, effectively utilizing free-air cooling.

Microsoft – Data Center Water Usage

Microsoft has committed to be water positive for its direct operations by 2030, which means that Microsoft will replenish more water than it consumes on a global basis. Particularly, Microsoft’s water consumption strategy has two main pillars:

• Reducing Water Use Intensity: The water Microsoft uses per megawatt of energy used for its operations
• Replenishing Water: In the water-stressed regions where Microsoft operates

Microsoft’s water consumption from its operations reached nearly 6.4 million cubic meters, which is equivalent to approximately 1.69 billion gallons or 6.4 billion liters. This represents a 34% increase in consumption compared to the previous year.

Microsoft’s Water Consumption from Operations

This total water consumption, calculated as the difference between total water withdrawals and total water discharges, was 6.4 million cubic meters. It was derived from Microsoft’s total water withdrawals of 10.7 million cubic meters (2.8 billion gallons or 10.7 billion liters) minus total water discharges of 4.3 million cubic meters (1.1 billion gallons or 4.3 billion liters).

Over the past year, Microsoft engaged in various replenishment projects, projected to yield over 15.6 million cubic meters of volumetric water benefits. This initiative increases the company’s cumulative total of water replenishment to 35 million cubic meters.

Water Strategies for Data Centers

Focusing on data centers, Microsoft has committed to reduce the water used in its evaporative cooled data centers globally by 95% by 2024. This reduction represents an estimated 1.5 billion gallons (5.7 billion liters) of water annually.

As an example, Microsoft is leveraging a method called adiabatic cooling, which uses outside air instead of water for cooling when temperatures are below 85 degrees Fahrenheit (29.4 degrees Celsius).

READ MORE: Microsoft Azure’s Data Center Locations

Google – Data Center Water Usage

Google has committed to replenish more water than it consumes by 2030 and support water security in communities where it operates. This commitment involves investing in community projects that replenish 120% of its water consumption across all offices and data centers globally. In simpler terms, Google intends to return 20% more fresh water to the environment than it uses each year.

To achieve its water commitments, Google is focusing on three areas:

1. Responsible Water Use: Enhance management of water resources across Google office campuses and data centers
2. Watersheds and Communities: Replenish Google’s water use and improve watershed health, while supporting ecosystems in water-stressed communities
3. Water Security with Technology: Share technology and tools that enable everyone to predict, prevent, and recover from water stress

Water Metrics in Google’s Data Centers

Google’s data centers, which are essential for powering its cloud regions and core products like Gmail, Google Drive, Google Maps, Google Photos, Google Play, Search, and YouTube, primarily use water for cooling purposes.

Compared to air-cooled data centers, Google’s water-cooled facilities are approximately 10% more energy-efficient and emit around 10% less carbon. Additionally, water is utilized within Google’s supply chain, particularly in manufacturing data center equipment.

In terms of consumption, Google’s global data center portfolio used approximately 5.2 billion gallons (19.8 billion liters) of water. This volume is comparable to the amount needed to irrigate 35 golf courses annually in the southwestern United States.

The consumption figure was calculated by subtracting Google’s total water discharged of 1.4 billion gallons (5.3 billion liters) from its total water withdrawn of 6.6 billion gallons (25.1 billion liters).

Google Data Centers – Annual Water Consumption

(Units in millions for gallons and liters)

Notably, the average Google data center consumed 550,000 gallons (2.1 million liters) of water per day, equivalent to 200 million gallons (760 million liters) of water annually.

READ MORE: Google Cloud’s Data Center Locations

Facebook (Meta Platforms) – Data Center Water Usage

Facebook, part of Meta Platforms, has committed to be water positive by 2030, meaning the company will restore more water to the environment than it consumes (i.e., evaporates) for its global operations. To achieve this goal, Meta will restore 200% of the water it consumes in high water-stressed areas, and 100% of the water it consumes in medium water-stressed areas.

Meta follows a water usage strategy that focuses on:

1. Sourcing water responsibly
2. Driving water efficiency across its facilities and operations
3. Investing in critical water restoration projects in the same watersheds where its facilities are located

Facebook (Meta Platforms) uses water at its data centers to cool servers and maintain optimal humidity. Meta’s total data center portfolio consumption was 663 million gallons (2.5 billion liters) of water, comprised of withdrawal of 956 million gallons (3.6 billion liters) of water, less discharge of 293 million gallons (1.1 billion liters) of water.

Facebook (Meta) Data Centers – Annual Water Withdrawal

(Units in millions for gallons and liters)

Over 99% of Meta’s total water withdrawal was sourced from third-party water, such as municipal water supplies, with the remaining less than 1% coming from groundwater.

Additionally, Meta restored 621 million gallons (2.35 billion liters) of water throughout its operations during the past year. Looking forward, Meta has contracted for the restoration of 1.9 billion gallons (7.2 billion liters) of water per year, once all projects are online and fully implemented.

Water Usage Effectiveness (WUE)

Data center buildings which Facebook (Meta Platforms) completed recently exhibit a water usage effectiveness (WUE) metric of 0.20 liters of water per kilowatt-hour (L/kWh) of electricity used. Historically, the company’s annual data center water usage effectiveness (WUE) metrics have trended as follows:

Facebook (Meta) – Water Usage Effectiveness (WUE)

(Liters of Water per Kilowatt-Hour of Electricity Used)

According to Facebook (Meta Platforms), the company’s innovative server cooling process enabled its recently built data centers to be at least 80% more water efficient than the average data center across its portfolio.

READ MORE: Meta Platforms (Facebook) Data Center Locations

Apple – Data Center Water Usage

Apple is committed to reduce water impacts in the manufacturing of its products, use of its services, and operation of its facilities (offices, data centers, and retail stores). Specifically, Apple’s efforts to address the water footprint of its corporate sites and of its suppliers’ sites focus on the following key efforts:

• Using water efficiently
• Minimizing freshwater use by expanding the use of alternative water sources, including on-site reuse
• Improving the quality of water it discharges
• Protecting shared water resources and keeping watersheds healthy for all who rely on them

Apple’s global corporate facilities, including data centers, retail stores, distribution centers, and offices, consumed 848 million gallons (3.2 billion liters) of water. This figure is the result of withdrawing 1.53 billion gallons (5.8 billion liters) and discharging 679 million gallons (2.6 billion liters).

To date, Apple has implemented server upgrades and replacements at its data centers, achieving a reduction of 60 million gallons (227 million liters) in annual cooling water usage. Furthermore, through its partnership with the Alliance for Water Stewardship (AWS), Apple is on course to certify all its owned and operated data centers in accordance with the AWS Standard by 2025.

READ MORE: Apple’s Data Center Locations