The Infrastructure Effect: Safeguarding drinking water for the future

This post is part of a series exploring the impacts of federal investments in home electrification, transportation, supply chains, and climate resilience.

Climate change will put increasing pressure on aging infrastructure, imposing a range of hazards for drinking water utilities, Carnegie Mellon University research shows.

State and local policymakers who don’t plan for climate change will be ill-prepared for its consequences on their communities.

A study from Carnegie Mellon University analyzed seven climate hazards - including extreme heat, wildfires, and flooding - for more than 40,000 drinking water utilities serving 283 million people across the United States.

The researchers found that by 2050, all drinking water utilities are projected to experience changes in at least one climate change hazard, and most are exposed to at least three hazards. Some of the findings:

• Water supply stress: Approximately 8,000 systems (∼19% of total) are projected to experience moderate or greater water supply stress by 2050. These utilities serve around 100 million people. The West and Southwest regions have the most utilities exposed to these risks.

• Extreme heat: Almost all drinking water utilities are projected to experience increases in extreme heat by 2050, with 91% (39,050 systems) projected to see at least a 2 ℃ increase in maximum 5-day period temperature. These increases are of special concern in regions that historically do not experience long periods of high temperatures, including the Ohio Valley, Upper Midwest, Northern Rockies and Plains regions. Systems in these regions may not have water treatment resilience mechanisms in place to deal with these levels of heat.

• Increase energy demands: By 2050, utilities are projected to experience an average of 6% increase in the energy required to deliver a unit of drinking water, which includes extraction, conveyance, treatment, and distribution. Utilities in the Southwest and South regions are projected to see the largest increases.

These climate change hazards can affect utilities in different ways - water supply stress affects the availability of drinking water resources, heat waves affect utility infrastructure and energy demand presents operational challenges for utilities.

Carnegie Mellon’s combined climate hazard index allows drinking water utilities to compare climate hazard risk among systems of different sizes, locations, and source water supplies. Utilities can use this information to help with climate adaptation efforts, but federal funding should be targeted to utilities with higher combined hazard index values.

The Infrastructure Investment and Jobs Act of 2021 authorized $11.7 billion dollars for Drinking Water State Revolving Funds, which supports infrastructure investments through grants and low-interest loans. The EPA recommends utilities use these funds for projects that make the utility more resilient, including through climate adaptation efforts. Also included in the IIJA was funding for technical assistance and the establishment of the Drinking Water System Infrastructure Resilience and Sustainability Program, which awards grants specifically for small and disadvantaged public water systems. 

A separate Carnegie Mellon study suggests considering multiple climate projection datasets when developing resilience and adaptation plans. 

The researchers looked at 48 city climate plans and how they account for how extreme rainfall could affect stormwater infrastructure. Stormwater infrastructure collects and conveys stormwater runoff during rainfall events, prevents flooding and damage, and allows safe travel through the transportation network.

They find that if cities are assessing climate impacts with only one climate projection dataset to inform stormwater design decisions, they may not adequately protect against future rainfall volumes. 

CMU created an open dataset for 77 cities to assess climate resilience for stormwater strategies across five commonly used downscaled datasets, especially for critical infrastructure projects where a higher level of resilience is desired.

The studies show the importance of integrating climate change considerations into all aspects of water management and infrastructure planning. Proactive, targeted, and regionally informed policies, coupled with strategic investments, are essential to safeguard this critical resource for future generations.