Nearly 27 million Americans, or 8% of the U.S. population, live in areas where water demand consistently approaches or exceeds naturally available water supply. Until now, accessing comprehensive water availability information required navigating fragmented datasets across multiple agencies. The new tool eliminates many of those barriers.

The USGS National Water Availability Assessment Data Companion provides water managers, agricultural communities and researchers with detailed information about water supply and demand across approximately 80,000 watersheds nationwide. 

“While the United States has abundant water nationally, regional imbalances between supply and demand may create water challenges affecting millions of Americans,” said Shirley Leung, lead scientist. “This tool can help decision-makers understand whether challenges may stem from limited natural water supply, high demand, or both. This information is helpful for effective water planning.”

There are also water‑rich regions of the country where communities and water managers may use the tool to identify potential economic opportunities tied to their water supply, as well as to support long‑term planning to preserve and protect this vital resource.

What Makes It Unique

More than 224 billion gallons of freshwater are withdrawn daily across the lower 48 states for crop irrigation, municipal water supply and thermoelectric power generation. Until now, understanding where and when this demand intersects with natural water availability required comprehensive data that has been difficult to access. 

The National Water Availability Assessment Data Companion is the first tool to provide water availability data from individual watersheds on a national scale, using USGS models that integrate monitoring data, satellite observations and climate information. Users can access up to 40 years of monthly water supply information, including streamflow, snowpack and soil moisture data. Data comparing supply and demand are available from 2009 to 2020. Public supply, crop irrigation and water supply data extend from 2000 to 2020. 

“Public access to data is a cornerstone of the National Water Availability Assessment,” said Leung. “What once required significant resources and time can now be done in minutes, giving communities of all sizes the same foundation for water planning.”

Regional Patterns

The data reveal how water availability varies significantly across the country: 

The Mississippi Embayment—including parts of Arkansas, Louisiana and Mississippi— receives the nation’s fourth-highest natural water supply from rainfall and river flows. However, in 42% of the area, intensive crop irrigation for rice and cotton drives water demand to levels that approach or exceed natural supply.

The Central and Southern High Plains—including areas of Kansas, Nebraska, Oklahoma and Texas—face challenges from both limited precipitation and substantial irrigation demand for corn, soybean and cotton crops.

The Southwest—including portions of Arizona, Nevada and New Mexico—has naturally limited water supply combined with municipal and agricultural demands that strain available resources.

California's Central Valley exhibits significant seasonal variation. Water supply-demand imbalances increase substantially during summer months when irrigation demands peak and natural supply decreases.

Accessing the Data

Users can explore conditions for any watershed, compare regions, identify seasonal patterns and download complete datasets in multiple formats for custom analysis. Technical users can access the data through web services and easily integrate it into their local workflows for a variety of purposes, such as building models, developing tools, or conducting data analysis.

Access the National Water Availability Assessment Data Companion online at no charge.