Southern Maryland residents drawing water from the Potomac River system face heightened drought concerns as the river heads into summer at near-record low levels, prompting increased monitoring by regional water officials.
The U.S. Drought Monitor released April 16, 2026, shows 31 percent of the Washington metropolitan region in severe drought, with the remaining area in moderate drought. River flow at Little Falls stands close to the lowest on record for this time of year, based on more than 130 years of data.
Michael Nardolilli, executive director of the Interstate Commission on the Potomac River Basin, stated the river is “at its lowest point that it’s ever been for this particular date.” The commission’s first Water Supply Outlook for 2026, released earlier in April, indicates an above-normal probability of releases from backup reservoirs this summer and fall.
Drinking water supplies for the District of Columbia, suburban Maryland and Northern Virginia remain adequate for now. However, the three major water providers — D.C. Water, WSSC Water and Fairfax Water — share access to three backup reservoirs. The closest, Little Seneca Reservoir in Montgomery County’s Black Hill Regional Park, can reach downstream intakes in about one day. Farther upstream are Jennings Randolph Lake on the Maryland-West Virginia border and Savage River Reservoir in northwest Maryland.
Nardolilli noted it has been more than 10 years since the Army Corps of Engineers released water from these reservoirs. Previous releases occurred during droughts from 1999 to 2002 and in 2010. “The likelihood of releases from the backup reservoirs is increasing,” he said.
As of April 1, the Potomac basin upstream of Washington received 37.6 inches of rain over the past 12 months, 2.2 inches below normal. Streamflow and groundwater levels also sit below average. While some rain is forecast in coming weeks, rising temperatures will boost evaporation and plant uptake, adding strain.
A newer factor is the expansion of large data centers in the region, which Nardolilli described as “an additional drain on resources.” American Rivers named the Potomac the most endangered river in the United States for 2026, citing data center growth alongside drought and infrastructure issues.
In St. Mary’s County, drought conditions persist. The county falls under warning status for groundwater in Maryland’s hydrologic assessment, with 100 percent of the area affected by drought according to the April 16 monitor. Declining groundwater levels led the St. Mary’s County Health Department to suspend seasonal perc testing for septic systems in April 2026.
The Metropolitan Washington Council of Governments currently lists regional drought conditions as normal. Nardolilli expects the Drought Coordination Technical Committee to consider recommending a drought watch when it meets in June. Such a step would include stronger public calls for water conservation.
Parts of Pennsylvania, Maryland and Virginia within the Potomac basin already show significant drought. Southern Maryland communities, including those in St. Mary’s, Calvert and Charles counties, rely on a mix of groundwater and surface water sources tied to the broader Potomac watershed.
Local governments and water utilities continue routine monitoring. Residents can track conditions through the Interstate Commission on the Potomac River Basin website and Maryland Department of the Environment drought pages. Conservation measures, such as limiting outdoor watering, become more critical if flows drop further.
The current situation underscores the region’s vulnerability to multi-year dry patterns. Water supply planners emphasize that proactive management of the shared Potomac system has prevented shortages in past droughts, but low flows this spring signal the need for continued vigilance heading into peak summer demand.
Southern Maryland families and businesses can prepare by reviewing local water restrictions, fixing leaks and adopting efficient habits. While no mandatory restrictions are in place, voluntary conservation supports the shared resource that serves millions.
