The Agriculture Work Group of the Loudoun County Preservation and Conservation Coalition has just issued their groundwater report. The Agriculture Work Group was alarmed not only at the drought conditions that have plagued the small well systems and resulted in water restrictions the past few summers, but also in the falling water levels in most areas. They created the report to heighten awareness of the need for proactive groundwater planning. The report demonstrates the need for County officials (Board of Supervisors, town mayors and others) to act now to prevent a water crisis.
The full report is available at this link. I do recommend
reading the full report if you have the time. It is full of information on groundwater. I have excerpted from the
report, the Loudoun County Preservation and Conservation Coalition overview
and the news release below:
The report includes a review of existing data for
groundwater in Loudoun County, in conjunction with groundwater science to
evaluate the potential threat to this essential resource. Historical data from
the 1980s along with data collected since 2000 (when Loudoun installed some of
its own monitoring wells) point to a strong conclusion that groundwater
resources in much of western Loudoun are being withdrawn at an unsustainable
rate- faster than they can be replenished by natural rain and snowfall.
The reason for the water table decline appears to be the
result of a combination of climate change, periodic and/or extended drought,
and land development including residential homes in most areas.
A two-year extended drought persisted from 2023 through June
2025 which is a reminder of the impact of previous historically severe droughts
of the 1930s and the more recent droughts in 2001 and 2002. The difference in
2025, however, is that weather patterns have changed to hotter and humid
summers with continued extended drought conditions persisting for months at a
time, so the impact of the drought to drinking water appears to be more severe.
The drinking water supply in Loudoun County is dominated in
eastern Loudoun by surface water as supplied by Loudoun Water and groundwater
in western Loudoun. Both Loudoun Water and the Town of Leesburg currently draw
their water from the Potomac River. The Goose Creek Reservoir is idle and
serves as a backup supply of water. In western Loudoun, groundwater is the
dominant source of drinking water and within the towns and community areas,
wells provide most of the water. Purcellville has a small reservoir (J.T.
Hirst) which serves about one-half of the Town’s residents.
Today, agriculture remains a vital industry, supporting
commercial livestock production, horticulture, farmers markets, and
agritourism. The county’s agricultural sector not only preserves its rural
heritage, but also drives economic sustainability through local farming
initiatives, soil conservation efforts, and agribusiness development. As of
June 2025, farmers in Loudoun County experienced the socioeconomic impact of
the new normal of extended drought conditions in 2023-2024 and into mid-June of
2025
The Agriculture Work Group found clear evidence that
Loudoun’s groundwater resources are being appreciably depleted. This is a
situation that will only continue to become worse. The water table in the
County has declined significantly over the past few decades and there are
numerous reports of wells, ponds, and springs that have gone dry. Although
previously conducted analyses of streamflow records have not indicated surface
water impacts, there is obvious visual evidence that discharge in many streams
is drying up in late summer and early fall.
They found reasons to believe that the overall water table
has dropped 10 to 40 feet since the 1980s. The number of wells with the water
table falling below the top of bedrock (without any pumping) has been
increasing. With a lowered relative position of the water table there may be
less stored water in the soil and overburden (regolith) and in wells, thus
impacting overall sustainability of groundwater water resources. With a falling
water table groundwater is no longer connected to the streams that can no
longer draw water to maintain flow.
Based on field observations before 2000 and after 2000, the following changes have occurred with land use
changes and development:
- Wells are drilled deeper,
- Surface runoff has increased,
- Infiltration (recharge to groundwater) has decreased,
- Some ponds, wells and springs have permanently gone dry,
- The elevation of the water table has dropped from mostly above the top of bedrock elevation to below the top of bedrock,
- Groundwater storage within the weathered bedrock has diminished, and
- Locally, some streams and creeks are no longer “gaining” discharge from groundwater but are “losing” water in the stream to groundwater, at least temporarily, when wells are pumped.
The Agriculture Work Group states that proactive planning is
essential to foresee and forestall problems and unnecessarily expensive
solutions. Increased analysis and monitoring of existing data, completion of
the well system that was originally proposed along with a plan to better manage
and protect groundwater supplies is important for the long-term health and
vitality of those dependent on groundwater in the face of increasingly
unpredictable weather patterns.
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