Planning Today’s Water Systems for Tomorrow’s Communities

Across the United States and around the world, water infrastructure is aging. Many drinking water, wastewater, flood protection, and distribution systems are approaching or exceeding their intended service lives, increasing the need for maintenance, rehabilitation, and replacement. At the same time, population aging is one of the most consequential demographic shifts facing societies, particularly in developed countries. These two converging trends create a growing challenge: aging water infrastructure increasingly serves communities that are themselves aging.

This convergence creates what Farshid Vahedifard, professor and Louis Berger Chair in Civil and Environmental Engineering, and his collaborators describe as a “double aging” challenge: aging water infrastructure serving aging populations whose health vulnerabilities, workforce capacity, financial resources, and infrastructure needs may be very different from those of the communities for which these systems were originally designed. This challenge, along with their proposed infrastructure-society aging gap that can help inform future planning, is described in a recent publication in Nature Water.

“Infrastructure designed for yesterday’s society may no longer be appropriate for tomorrow,” said Vahedifard.  

The effects of aging populations on water infrastructure 

Although infrastructure systems like roads and bridges, electric power grids, and water infrastructure systems are inextricably linked to the communities that they serve, they’re not always built or planned with the changing nature of this relationship in mind. For example, consider a drinking water treatment plant built in the 1960s for a growing, young population with an expanding workforce and revenue base. Sixty years later, that same aging system may require substantial investment while serving an older, more vulnerable, and shrinking community with declining revenue. 

Vahedifard and his collaborators introduced the infrastructure-society aging gap (ISAG): a framework to help engineers recognize, quantify, and account for this everchanging relationship between infrastructure and communities. The framework could help ensure that the age of a population is considered a priority when building and upgrading water treatment and distribution systems, now and decades into the future. 

As populations and infrastructure simultaneously age, their interactions can affect water systems and the communities they serve in several important ways. First, the water-sector workforce, including operators and engineers, may retire faster than can be replaced, creating workforce shortages. Additionally, aging societies may become more vulnerable to infrastructure failures. Economic resources may dwindle as public budgets spend more money to support health care and long-term care in older communities, competing with available resources for infrastructure improvements. 

“Another important effect of aging populations and aging water infrastructure stems from geography,” explained Vahedifard. “Aging populations are rarely evenly distributed. Social and economic vulnerability is often most pronounced in rural regions, many of which also contain older infrastructure.” 

Recognizing these effects is the first step toward improving how water infrastructure serves communities over time. ISAG is intended to capture the evolving gap between the condition and capacity of infrastructure and the changing needs, vulnerabilities, and resources of the populations that depend on it. Accounting for this gap can help engineers and decision-makers make more informed choices about where, when, and how to maintain, upgrade, and adapt water infrastructure. 

Proactively meeting communities' water needs 

“The goal of ISAG-informed planning is to reshape priorities depending on the characteristics and trajectory of the community being served,” Vahedifard said. “For example, in younger and growing populations, the emphasis may be on expanding system capacity. In older communities experiencing population decline, utilities may need to place greater emphasis on protecting vulnerable residents, maintaining essential services, and planning infrastructure investments in the face of a changing revenue base.” 

These challenges can also reinforce one another. Deteriorating infrastructure and declining services can contribute to population loss, which can further reduce a community’s revenue base and its capacity to invest in infrastructure. This can lead to deferred maintenance and further deterioration, creating what Vahedifard and his collaborators describe as an infrastructure-society aging decline spiral.

The work also has broader implications for global water policy. The article is part of a series contributing to the 2026 United Nations Water Conference, supported by the United Nations University Institute for Water, Environment and Health (UNU-INWEH) as part of the UN-Water initiative to support evidence-based policymaking in the water sector. The authors call for demographic change to be more systematically incorporated into long-term water infrastructure planning and investment.

This framework contributes to Vahedifard’s growing body of work aimed at addressing infrastructure risks before they become crises. His research emphasizes a proactive approach that considers not only how infrastructure will age, but also how the communities that depend on it will change over time. 

Ultimately, the work asks planners and engineers to consider not only the age of infrastructure, but also who the infrastructure will serve over its lifetime, and how their needs and capacities will change.

Learn more about Vahedifard’s work.