Despite access to Lake Michigan, parts of the Chicago region face water supply challenges that will worsen without coordinated conservation efforts. Accurate demand forecasts help the state, counties, and communities plan for sustainable water use.

In 2024, Illinois-Indiana Sea Grant and the Chicago Metropolitan Agency for Planning (CMAP) completed the updated Northeastern Illinois Regional Water Demand Forecast to 2050, a key tool in long-term water supply planning. This new version includes the latest population numbers, plus adjustments were made based on how successfully the previous forecast predicted water demand. Our role in this effort included technical assistance in economics by developing guidance, training CMAP planners in water demand forecasting, and troubleshooting as needed.

The Illinois State Water Survey uses demand forecast data to inform its water supply modeling. In addition, forecasts provide insights to over 200 communities in seven counties (home to 8.5 million people) as they assess water sufficiency and explore conservation and alternative sources. As part of the forecast update, sustainable supply values were developed for water sources in the region and these values are compared to demand, giving first-ever numerical targets of expected water supply shortages.