The relationship between water and energy, commonly referred to as the water-energy nexus, is one of the most critical and often overlooked challenges in sustainability today. Simply put, it takes water to produce energy, and it takes energy to produce and deliver water. Recognizing and optimizing this interdependence presents a major opportunity for utilities, businesses, and communities.
At a national scale, the numbers are striking. The U.S. energy sector withdraws approximately 58 trillion gallons of water each year, with about 3.5 trillion gallons consumed, equaling roughly 10% of the total U.S. water consumption. Much of this water is used for cooling power plants, making energy production one of the largest drivers of water demand.
At the same time, producing and delivering water requires a substantial amount of energy. According to the U.S. Environmental Protection Agency, drinking water and wastewater systems are often the largest energy users in municipalities, accounting for 30–40% of total energy consumption. Nationally, these systems use about 2% of U.S. energy and generate over 45 million tons of greenhouse gas emissions each year.
This interconnected relationship means that saving water saves energy and saving energy saves water.
Bringing the Nexus to Life
The water-energy nexus becomes more tangible when we look at everyday examples. Consider lighting: switching from a compact fluorescent bulb to an LED can reduce annual energy use by 35 kWh, which also saves about 14 gallons of water used in energy production.
Similarly, water efficiency improvements carry embedded energy savings. A high-efficiency toilet can save around 12,000 gallons of water per year, which translates to measurable energy reductions in water treatment and distribution.
These examples highlight a key takeaway: decisions that appear to affect only water or energy often impact both.
Opportunities Across Sectors
The nexus is especially relevant in industrial, commercial, and institutional (ICI) settings, where water and energy systems are tightly linked. Equipment choices, such as air-cooled versus water-cooled systems, can significantly affect both utility costs and resource use.
For instance, converting a water-cooled dental vacuum system to an air-cooled system can save thousands of gallons of water per day and generate annual cost savings with a relatively short payback period.
However, the nexus also requires careful evaluation. In some cases, reducing water use may increase energy consumption, such as with certain cooling systems. A holistic approach is essential to ensure that improvements in one area do not create unintended consequences in another.
The Role of Utilities and Systems Thinking
Utilities play a key role in advancing water and energy efficiency, both within their own operations and in how they support their customers.
Within their own systems, utilities can improve efficiency by optimizing infrastructure and operations. One example is district cooling, a centralized approach where chilled water is produced at a central plant and distributed to multiple buildings. By serving multiple buildings from a single, optimized system, district cooling can significantly reduce overall energy use compared to individual building systems.
Utilities can also identify cost-saving opportunities by evaluating energy rate structures, or tariffs. These pricing structures vary based on demand, usage patterns, and time of day. By reviewing historical energy use and comparing available rate options, utilities can often reduce costs without major infrastructure changes.
Beyond their own operations, utilities are also in a unique position to help customers improve efficiency. By providing data-driven insights into water and energy use, utilities can help identify practical opportunities for improvement. This may include recommendations for equipment upgrades, operational changes, and estimated costs, savings, and payback timelines, giving customers the information they need to make informed decisions.
Taking this dual approach, improving internal operations while supporting customer efficiency, allows utilities to maximize system-wide benefits and drive more meaningful, long-term resource savings.
Moving Forward
Addressing the water-energy nexus requires integrated thinking. Rather than treating water and energy as separate systems, organizations must evaluate them together to unlock the greatest efficiencies.
Whether through technology upgrades, operational improvements, or policy changes, the path forward is clear: smarter resource management delivers both economic and environmental benefits.
In a world facing increasing water scarcity and rising energy demands, leveraging the water-energy nexus isn’t just an opportunity, it’s a necessity.
We design solutions to the world’s greatest water and telecommunications challenges. We’re always looking for exceptional talent to join our outstanding teams.
