Water Pledge

The corporate giants that behind the data center explosion in Northern Virginia have  pledged (from Alphabet, Meta, Amazon and Microsoft) to be water positive- to replenish the freshwater volume that they consume by 2030, and help restore and improve the quality of water and health of ecosystems in the communities where they operate. Alphabet and Microsoft have pledged to replenish 120% of the fresh water they consume.

Water is our most valuable resource and how we manage its use or allow its abuse may determine the fate of our country and mankind. On earth all the water that ever was or will be is here right now and has been here for over 4 billion years. There is no mechanism on earth for making or destroying water.

 More than 97% of the Earth’s water lies within the oceans. The remaining 2.8% is the "freshwater" within the land masses. The land masses water contains all the freshwater on the planet- 77% in icecaps and glaciers and the remaining freshwater is stored primarily in the subsurface as groundwater with a tiny fraction of a percent of water flows as rivers or is stored in lakes which are renewed by rainfall (or snow). Rain drops fall to earth and will evaporate, infiltrate into the soil, recharge groundwater or flow along the ground to a stream and ultimately flow into rivers and to the ocean-moving, always moving.

Mankind has interrupted the flow of streams and rivers to the oceans by diverting water for irrigation, withdrawing drinking water and building reservoirs. We have also interrupted the recharge of groundwater by changing land use, covering it with buildings, driveways, roads, walkways and other impervious surfaces which change the hydrology of the site reducing groundwater recharge in the surrounding area. 

The Gravity Recovery and Climate Experiment (GRACE) satellite mission from the National Aeronautics Space Administration (NASA) has been collecting data for more than two decades. The GRACE satellites measure monthly changes in total earth water storage by using measured gravity anomalies. In the first decade scientists found that more than one third of Earth's 37 largest groundwater basins are using up their groundwater faster than it is being replaced. Additional data has only confirmed the finding. 

Throughout history surface water served as the principal freshwater supply used by mankind. However, in recent decades as mankind’s demand for water has surpassed surface supplies and our ability to access groundwater has increased with technology, groundwater has become essential. Fresh surface water can no longer support the needs of 8 billion people. Accessing groundwater allowed populations to increase and provide reliable water as surface water has become less reliable and predictable as weather patterns change and regions experience extended droughts. The GRACE mission tells us we are using up the groundwater and we face a future with not enough water for our needs.

The United Nations projects that 68% of the projected 9 billion people that will be the earth’s population will live in urban areas by 2050. The water supply to the rapidly growing cities has become unstable because of changing rain patterns, increased impermeable surfaces and increased population and demand for water. The available supply of fresh water is limited to that naturally renewed by the hydrologic cycle or artificially replenished by the activities of mankind. Though it can still exceed water demands during unusually wet periods, during droughts it falls far below demand.

The Metropolitan Washington Council of Governments projects that  population in our region will reach nearly 6.8 million people by 2050 an increase of  1.1 million people. While our available water resources will not increase. Though only recently noticed by our communities, data centers use lots of water. Not at the magnitude of power use, but nonetheless they are estimated to use about 0.5 gallons of water for each kilowatt-hour consumed. Unfortunately, power usage and water usage at specific sites are guarded as trade secrets so I cannot project the power usage and water use as Northern Virginia's data center are fully built out.

We do know that Google reported in their last annual report that in 2022 their data centers used 5.2 billion gallons of water, which is a 20% increase from the previous year. In addition, it was reported that on average, a Google data center uses 450,000 gallons of water per day. (About as much as 6,400 people- which would be fine if there were one or even 10 data centers, but there are hundreds in Northern Virginia alone and more being built every day.

In cool and moderate climate regions, adiabatic cooling can be used for cooling the data servers, resulting in reduced energy and water consumption. During cooler months, outside air is directly drawn into the data center without using any water and during warmer months, the warm air is drawn through water-moistened pads. As the water in the pads evaporates, the air is chilled and pushed into the server halls. In warmer climates like Northern Virginia and other data center hubs in the United State water cooled system are used.

In a water-cooled system, water-cooled chillers and cooling towers located on top of the data center roofs produce chilled water, which is delivered to computer room air conditioners for cooling the entire building. These systems include the cooling towers, chillers, pumps, piping, heat exchangers / condensers, and air conditioner units in the computer rooms. Additionally, data centers need water for their humidification systems (to avoid static discharges) and facility maintenance. Water-based cooling using evaporative cooling systems are more common in Virginia, particularly for large data centers simply because it is more efficient and effective.

Traditionally, sustainability goals by the data center industry have focused on energy, but that trend is shifting. Changing climate and population growth are only exacerbating an existing problem. Large portions of the earth are experiencing water stress. Corporate water management efforts are shifting focus toward water replenishment and watershed health. Most data center companies typically target water replenishment as their water sustainability goal. The typical pledge is to replenish 120% of the freshwater volume that it consumes by 2030 and help restore and improve the quality of water and health of ecosystems in the communities where they operate.

Where exactly are the data center companies going to get this excess water, they plan to return more of than they use to communities? Obviously, they would have to take it from another watershed or somewhere else. Water is a zero-sum game here. No one is adding water to the watershed, but the data center companies only count fresh water. 

Loudoun County built a reclaimed water system to supply data centers more cheaply with water. The data centers loudly proclaim that they are using wastewater, not freshwater.  However, there are two problems with that. The expansion of data centers required more than that system could provide. The water from the Broad Run Wastewater Treatment plant was inadequate to serve all data centers and still provide adequate flow. The second problem is the discharge from Broad Run Wastewater treatment plant is upstream of the river intakes for Fairfax Water, WSSC, and the Washington Aqueduct. The Washington Metropolitan Area was previously drinking that reclaimed wastewater.

According to Loudoun County, Data center water use will have grown to an average 4 million gallons a day of potable water and 4 million gallons a day of reclaimed water by the end of this year- since in northern Virginia we indirectly drink the reclaimed water from UOSA and returned treated wastewater upstream to the Potomac, that is enough water to supply 100,000 people. The water demand, like the number of data centers, are growing very rapidly. Unfortunately, the water supply for the region is not growing. 

The Occoquan Reservoir, a locally essential portion of our water supply, is fed by the Occoquan River which receives up to 40 million gallons a day of the treated wastewater discharge of the Upper Occoquan Sewage Authority treatment plant, UOSA.  A significant portion of the flow (especially during dry periods) into the reservoir is recycled sewage. This has been true for decades because the region, though water rich, does not have enough water.

This treated wastewater is from areas supplied by the Potomac River (down river from the Broad Run release) or lake Manassas, so you do not end up with constantly recycling and concentrating the same impurities into the drinking water supply. These impurities include elevated salt levels and traces of  PFAS that have been found in the Occoquan Reservoir. The wastewater that originates from the Occoquan Reservoir served areas is treated at the HL Mooney Plant in Woodbridge and discharged into Neabsco Creek, a tributary of the Potomac River at Occoquan Bay.

Data center operators are making commitments to replenish water in the watersheds impacted by their operations. The projects they point to as examples range widely in scope from ecosystem protection and restoration to water rights reallocation. None of those kinds of projects would bring more water to the Washington Metropolitan Area, yet we have the lion share of data centers and now they are expanding to build in areas served by groundwater. They are destroying the groundwater recharge as they cover more and more of the ground with data centers, roads, driveways etc.

Climate change is only exacerbating an existing problem, we are growing and expanding our water demand beyond our available water resources. We need to manage our water resources to ensure that they are sustainable.