Written By Susan Miller, Public Affairs Manager, Fairfax Water
March 22 is World Water Day, which makes now a great time to learn more about your drinking water sources and how to protect them in light of the effects climate change on our watershed.
Water utilities, like Fairfax Water, rely on sustainable sources of water that can be treated to provide reliable, high-quality drinking water. Fairfax Water, which provides water to over 2 million people in the region, draws its water from two sources: the Potomac River and the Occoquan Reservoir.
Protecting the drinking water supply is essential for safeguarding human health, the environment, and the well-being of communities. This is especially important when there are cases of extreme weather such as heat waves, stronger storms, or changes in rainfall patterns. The following are recent examples of how extreme weather impacts the water supply.
During the summer of 2024, the area experienced unusually dry conditions and entered into a drought watch. Because of these conditions, the Potomac River had higher levels of organic materials — particularly algae — in the water. This resulted in a green sheen on the river surface. As a result, drinking water treatment plants on the Potomac River, including Fairfax Water’s Corbalis Treatment Plant, had to take extra measures to remove these materials from the water. This was an unprecedented event, yet our staff was up to the task and continued to provide high quality water to our customers.
This winter, Fairfax County experienced more snowfall than in the last several years. As a result, there was an increased use of winter salt on roads, sidewalks, and parking lots. Winter salt keeps us safe while we are on the move, but it also leads to higher levels of salt in the region’s drinking water supplies. Unfortunately, salt dissolves in water, forming sodium and chloride, which cannot be removed via traditional drinking water and wastewater treatment processes, such as filtration. As a result, sodium and chloride concentrations have been steadily increasing in the watershed. Excess sodium in drinking water is a health concern for people on low sodium diets and with medical conditions such as high blood pressure.
Fairfax Water has been working with the Virginia Tech Occoquan Watershed Monitoring Laboratory to analyze salt trends and explore solutions to increased salinity in the Occoquan watershed.
While we cannot control the weather, we can mitigate the effects of our actions on our drinking water sources. Taking action to protect the watershed and waterways that lead to the Potomac River and Occoquan Reservoir will mean that our excellent water quality will continue for the future generations of Fairfax County residents.
Visit our Water Supply webpage to learn more about this important topic and steps you can take to protect our drinking water supply.
Susan is the Manager of Public Affairs at Fairfax Water. She has worked at Fairfax Water for 23 years, in both the water quality laboratory and public affairs. Susan is a member of the American Water Works Association and serves on the Metropolitan Washington Council of Governments’ Community Engagement Campaign for drinking water utilities in the DC area.
Climate Matters is the blog of Fairfax County’s Office of Environmental and Energy Coordination, where we share stories, insights and information related to climate change and environmental sustainability. Posts are written by knowledgeable and passionate OEEC staff members and guest authors. To read all blog posts, visit Climate Matters.