Climate Change and Drought

 It rained a bit over the weekend, but we remain in drought and a significant precipitation deficit. . 

Data from rain gauge PW VA-15, 5.5 miles N of Haymarket

The long predicted impacts of climate change are arriving. Not only is Earth’s temperature increasing, polar ice melting, and the northern U.S. is seeing increased summer heat. We have all seen the impacts of wildfires. Hurricane intensity has increased. Droughts are becoming more intense. There is tremendous uncertainty in projecting the future climate of the earth, especially at the regional scale. Though global climate models are continually being refined and improved, they do not capture complexity of the interrelations of earth’s land, water, and atmospheric systems that we do not yet fully understand.

Nonetheless about a decade ago, the Interstate Commission on the Potomac River Basin (ICPRB) engaged the U.S. Geological Survey to  complete a study of water supply availability and the health of the Potomac Watershed for various climate scenarios. The focus of their study was the Potomac River, which supplies water to the Washington Aqueduct, Washington Suburban Sanitary Commission (WSSC), and Fairfax Water who all funded the study. 

The climate models predict that precipitation will increase on a global scale, when dealing with only the Potomac River basin, the models differed on whether precipitation will increase or decrease. The models project that the total annual precipitation varies from plus 9% to minus 9% meaning that rainfall will stay within 4 inches of that average. It is to be noted, that year to year weather variations in rainfall in the region are very large, precipitation has varied from over 80 inches to below 20 inches in the past century.

Though annual rainfall increases in half of the climate change scenarios, flow in the Potomac River falls in most scenarios. Changes in both temperature and precipitation affect stream flows. Changes in rain or snow affect the amount of water that runs off the land surface and enters streams during rainfall. Precipitation also affects the amount of water recharging groundwater aquifers, which are the primary source of stream flow during dry weather periods. Increasing temperatures will cause more rain to be lost to evaporation from the soil, streams, and will increase transpiration, the water released to the atmosphere by plants. These increases in evaporation and transpiration will tend to reduce flow in streams which in turn reduces flow in the Potomac.

With rising population and land use and land cover changes -cutting down streamside vegetation and woodland buffers that once slowed and absorbed rains. Covering the ground with compacted and/or impervious surfaces.  The faster flow of storm water will not only reduce groundwater availability for private well owners like me, but reduce stream and river flow, cause floods and property damage. This will in turn require more and larger reservoirs to store the flood waters and  supply  water to the region, and additional water treatment to make the floodwaters suitable as water supply.

The study also predicted that average annual basin-wide evaporation and transpiration is predicted to increase by 6-8%. Groundwater recharge decreases under 83% of the climate scenarios.  The groundwater monitoring well up the road has experienced slow but continuous decline of one foot per decade over the last 20 or so years. The monitoring well east of Leesburg which has seen more development has fallen about 3 feet per decade over the same period after the change from open space to development. Land use and land cover change may be the cause. 

According to study results, the seasonal pattern of groundwater recharge does not change significantly under climate change, with January, February, and March remaining the months of greatest recharge. However, the average annual amount of groundwater that provides base flow to streams and the water in my well, is predicted to decrease in 16 out of the 18 scenarios by as much as 34% in one case. Looking below at what is happening over the last 20 years in Loudoun county is not a comforting picture. 

The U.S. Drought Monitor shows 62.39% of Virginia is experiencing abnormally dry to moderate drought conditions. Northern Virginia groundwater wells continue to exhibit much below normal water levels. The Shenandoah and Northern Virginia regions remain in emergency status for groundwater indicators, and the Roanoke and Northern Coastal Plain regions’ groundwater indicators were in warning status.

graph from David Ward, Loudoun County Presentation 10/2024

Location of the Wells

Loudoun Water

The following is excerpted from various Loudoun Water reports:

Loudoun Water is very much a reflection of its past, present and future. It buys water, treats its own water, manages the small water systems of semirural hamlets and provides reclaimed and potable water to the industrial demand of data center alley.

 Loudoun Water central system delivers water to its customers through a water distribution system consisting of 1,467 miles of water mains and 8 storage tanks with a storage capacity of over 18 million gallons. Loudoun Water currently purchases the majority of its drinking water from Fairfax Water which supplies approximately 18 million gallons per day (MGD).

The remainder of the water is supplied by the Trap Rock Water Treatment Plant drawn from the Potomac River. In the case of need Loudoun Water can also draw from Goose Creek Reservoir. The Trap Rock Water treatment plant is part of Loudoun Water’s Potomac Water Supply Program (PWSP). This includes an intake on the Potomac River, transmission lines, quarry storage and the treatment plant. The new plant has the ability to produce up to 20 MGD. Trap Rock became fully operational in January 2019 and currently produces approximately 10 MGD. As demands on the Loudoun Water system increase, it is currently assumed that the additional water will be purchased from Fairfax Water, as Loudoun Water anticipates continuing to operate Trap Rock at 10 MGD in the immediate future.

The cost of purchasing wholesale water from Fairfax County Water Authority (FCWA) has increased substantially over the past few years with the cost of purchased water increasing 42% between 2021 and 2024.  Loudoun Water will be increasing their water rates about 7% a year over the next few years to keep up with the costs of operating the system.

Loudoun Water also provides reclaimed water to data center customers located within the reclaimed water service area. The reclaimed water is produced at the Broad Run Water Reclamation Facility. The reclaimed water is distributed through a distribution system consisting of 22 miles of reclaimed mains. The reclaimed water system has delivered an average day amount of approximately 2.1 MGD of reclaimed water during 2024. It is anticipated that the volume of reclaimed water will grow to 3 million gallons a day on average in the next four years.

Loudoun Water also sells finished drinking water to data centers. It was reported that in 2023 Loudoun Water sold an average of 2.46 million gallons of water a day to data centers and that just keeps growing faster than the reclaimed water which is limited by location.

Loudoun Water has also taken over management of several community water systems. Community Water and Wastewater Systems are free-standing water and wastewater systems that generally draw from groundwater and utilize packaged waste systems. They are not connected to the central system. The community systems are: Beacon Hill, Creighton Farms, Selma Estates, The Reserve at Rokeby, and Village Green at Elysian Heights.

Loudoun Water Service Area

 

Assuring the Water Supply in the DMV

 Since the mid 1800’s, the Potomac River has been the source of drinking water for Washington DC. Today the Potomac River supplies 78% of the Washington, DC, metropolitan area’s water, with public water supply intakes for WSSC, the Washington Aqueduct, Fairfax Water and Loudoun Water located in the river upstream of the city. (For security reasons the exact locations of the water intakes is not disclosed and is blocked on Google Maps).

The Potomac River belongs to Maryland. In 1632 King Charles I granted to Lord Baltimore land from the “first fountain” of the Potomac River and along its south shore to the bay. There have been numerous legal cases over the centuries tightening up that boundary, but the fundamental ownership of the Potomac has not changed. There is; however, a multijurisdictional agreement to share the waters of the Potomac.

This agreement established the Interstate Commission on the Potomac River Basin (ICPRB) to cooperatively preserve water quality and to conserve and share water and related land resources of the Potomac River Basin. ICPRB is a non-regulatory agency that promotes water quality through watershed-based approaches. In 1979, the Commission created the Cooperative Water Supply operations on the Potomac (CO OP), which provides water usage forecasts and coordinates water management of the Upper Potomac Reservoirs and with the operations of the water utilities in the Washington metropolitan area.

The ICPRB was one of the first organizations with a congressional mandate to consider water resources on a watershed basis, rather than along political boundaries. However, now, we have reached the point in population density and development that during times of drought, natural flows on the Potomac are not always sufficient to allow water withdrawals by the utilities (including power generation which takes an awesome amount of water) while still maintaining a minimum flow in the river for sustaining aquatic resources. 

Current threats to the region’s water supply include severe droughts due to climate change, population and demand growth from data centers; increasing salinization of the Potomac and the watershed, and potential spills intentional or accidental polluting the Potomac River.  The region’s water supply relies heavily on the Potomac River and would be faced with moderate to severe water shortages in the event of an interruption in the Potomac River water supply.  Washington DC has the least storage. A shutdown of Potomac River intakes is predicted to result in a critical loss of water in some areas of the region after just one day.

During drought, water from three upstream reservoirs can be released if necessary to increase river flow, but it would take nine days for the water to reach the river intakes for the water treatment plants and be treated. Use of these upstream reservoirs would not be feasible in the case of an accidental or intentional spill. Plus, drought response in made tricky because of the time delay and that during an extreme drought the Jennings Randolph Reservoir is unlikely to be refilled. The ICPEB needs to carefully pick their moments for release. 

The public water suppliers in the region utilize the Potomac River as a source of raw water and distribute treated water to homes, businesses, and critical government facilities. Combined, they serve five million residents and over three million workers in the District and surrounding Maryland and Virginia. DC Water distributes the water treated from the Washington Aqueduct to Washington DC and only has enough water storage to supply the District for 24 hours, if not less. Without water, every facet of the city and government is affected. This vulnerability, though well-known regionally was laid bare last summer, when an algal bloom on the Potomac River overwhelmed the Dalecarlia Water Treatment Facility run by the Washington Aqueduct.

Drought remains a significant threat. We have not had a severe drought in this region in over 30 years, but the water basin has been in a low level drought for two years. The ICPRB allocates and manages water resources of the river through the management of the jointly owned Jennings Randolph Reservoir (built in 1981), Potomac River Low Flow Allocation Agreement (1978) and the Water Supply Coordination Agreement (1982) which designated a section of the ICPRB as responsible for allocating water resources during times of low flow. These steps improved reliability of the water supply and ensured maintenance of in-stream flows to meet minimum aquatic habitat requirements as defined by the Maryland Potomac River study in 1981. The section of ICPRB responsible for all this is known as the Section for Cooperative Water Supply Operations on the Potomac (CO-OP), and is formally empowered in its duty by the Water Supply Coordination Agreement. 

Currently,  for a limited period of time Fairfax Water can supply their entire system from the Occoquan Reservoir and that is one of the most powerful tools available for supply management. Fairfax Water is engaged in a long term plan of expansion of their water storage. The Vulcan Quarry almost adjacent to the Occoquan Reservoir will be converted to a reservoir in phases and continue to operate during phase 1 which will convert a portion of the quarry to a reservoir with storage of of about 1.8 billion gallons by 2035. Quarry operations will end with Phase II which will convert the remaining area to Fairfax Water reservoir with storage capacity of up to 15 billion gallons by 2085. The Vulcan Reservoir will store water from the Occoquan Watershed.  Loudoun is adding the Luck Quarry as a reservoir to store water diverted from the Potomac River. 

The ICPRB’s 2017 study, Washington Metropolitan Area Water Supply Alternatives, evaluated a suite of options to address increased drought severity in the face of climate change and identified use of a local quarry to create a backup supply for WSSC and the Washington Aqueduct to complement the Occoquan. This could allow the entire DMV to step off the Potomac for a period of time.  Another study, the National Capital Region Water Supply and Distribution System Redundancy Study, completed in 2016 for the Metropolitan Washington Council of Governments, also concluded that raw water storage in a local quarry was an effective solution to the threat of water shortages or disruptions to use of the Potomac River.

An existing quarry, Travilah Quarry, located in Montgomery County, Maryland, could be converted to a regional raw water storage reservoir with tunnels to carry water by gravity to  the Washington Aqueduct and WWWC  water treatment plants, bypassing the Potomac River. The estimated project cost was $800 million. Black & Veatch was retained by the Interstate Commission on the Potomac River Basin to perform the feasibility study of potential prerequisites for use of the Travilah Quarry as a raw water supply storage facility, to supplement the existing water supply for the Washington Suburban Sanitary Commission and the Washington Aqueduct.

The assessment was divided into two phases. The first phase of the study focused on studying characteristics of the quarry for water storage potential and water quality aspects. The study found the quarry suitable for raw water storage:

• The current storage available in the Quarry is approximately 7.3 billion gallons (smaller than the Occoquan Reservoir).
• However, the ultimate storage in the Quarry could reach 17.4 BG, based on the mining plans and quarry reservoir pool elevation. This capacity is expected to be available sometime around 2060
• It is expected that stored water will be in the range of available water treatment technologies. The management of water quality can be accomplished through inlet/outlet design and pumping strategies.

The second phase assessed potential options for conveyance, pumping and presents life cycle costs for different alternatives. It includes a conceptual design and layout of the infrastructure necessary to convey water from the quarry and plant to the Washington Aqueduct and ultimately concluded that the Conveyance Tunnel connection to the Great Falls was the better solution in terms of constructability, operations, cost and community acceptance. The tunnel can be built without much interference with the existing utilities and surface features. Because of the existing infrastructure at Great Falls, the consultant expected that this alternative offers a relatively compact system in terms of ease of system integration and O&M.

People Age at Different Rates

 

Elliott ML, Belsky DW, Knodt AR, Ireland D, Melzer TR, Poulton R, Ramrakha S, Caspi A, Moffitt TE, Hariri AR. Brain-age in midlife is associated with accelerated biological aging and cognitive decline in a longitudinal birth cohort. Mol Psychiatry. 2021 Aug;26(8):3829-3838. doi: 10.1038/s41380-019-0626-7. Epub 2019 Dec 10. PMID: 31822815; PMCID: PMC7282987.

from Elliott et al

This spring and summer my husband and I turn 70. We are old – three score and ten.  According to the Dunedin Study, Chronological age is a poor proxy for biological age, though they have only measured aging up to 45 chronological years so far.

The Dunedin Study covers the aging process in in a group of just over a thousand people born in 1972 or 1973 in Dunedin, New Zealand from age 26 to 45 years old (so far) and reports on the study participants aging process. It is an aging study that has been ongoing for over 20 years.

The researchers tested associations between midlife biological aging and indicators of future frailty risk in the Dunedin cohort of 1,037 infants born the same year and followed (so far) to age 45. Participants’ ‘Pace of Aging’ was quantified by tracking declining function in 19 biomarkers indexing the cardiovascular, metabolic, renal, immune, dental and pulmonary systems across ages 26, 32, 38 and 45 years. At age 45 in 2019, participants with faster Pace of Aging had more cognitive difficulties, signs of advanced brain aging, diminished sensory–motor functions, older appearances and more pessimistic perceptions of aging.

from Elliott et al

Among older adults of the same chronological age, those with accelerated biological aging (as measured by blood and DNA methylation biomarkers) are more likely to develop heart disease, diabetes and cancer and have a higher rate of cognitive decline, disability and mortality. Because all study members were born in 1972–1973, the differences in biological aging can be directly measured. The Dunedin Study has very low attrition rates; the full range of health is represented by the group. The researchers have so far  collected four waves of biological measurements from age 26 to age 45—a unique dataset allowing for more accurate estimates of biological aging. Fourth, although age-related diseases are uncommon in midlife, study members were assessed at age 45 with a battery of established measures that are commonly used in geriatric settings to predict frailty, morbidity and mortality.

In the Dunedin cohort of midlife adults, biomarkers examined by the researchers showed a pattern of age-dependent decline in the functioning of multiple organ systems over the 20-year study period.

However, study members showed wide variation in their Pace of Aging. Over the two decades in which we measured biological aging, the study member with the slowest Pace of Aging aged by just 0.40 biological years per chronological year, while the study member with the fastest Pace of Aging accrued 2.44 biological years per chronological year  

from Elliott et al

Shifts in Water Cycle

 

Luis Samaniego, Permanent shifts in the global water cycle.Science387,1348-1350(2025).DOI:10.1126/science.adw5851

Ki-Weon Seo et al. , Abrupt sea level rise and Earth’s gradual pole shift reveal permanent hydrological regime changes in the 21st century.Science387,1408-1413(2025).DOI:10.1126/science.adq6529

Below are excerpts from the above cited articles

According to a recently published peer reviewed study, global water storage within the land (as groundwater, stream flow and lakes), the source of most fresh water storage,  has been steadily declining in this century. The study found a substantial loss of approximately 1.6 gigatonnes of water  in the early 21st century. Regions in East and Central Asia, Central Africa, and North and South America have shown substantial depletion in soil moisture over this period. The authors also claim the findings  indicate that this lost water within the land area has not recovered to previous levels. This ongoing and persistent decline suggests that the negative shift in soil moisture may be irreversible because of prolonged drought conditions and reduced precipitation in certain regions.

Generally, droughts begin with precipitation deficits, like we are having here in Northern Virginia. If this condition persists it leads to an overall depletion of terrestrial water storage, including soil moisture (SM), groundwater, and water in streams and lakes. However, there are huge challenges in measuring terrestrial water storage, especially the measurement of groundwater and root-zone soil moisture. Also, we had a limited understanding of terrestrial water storage depletion at continental scales until the development of satellite gravity missions. Observations from the Gravity Recovery and Climate Experiment, GRACE, (May 2002 to May 2017) and the  GRACE Follow-On (June 2018 to present) missions provide continental-scale observations of terrestrial water storage changes. These changes serve as a proxy indicator of hydrological drought.

The data from the GRACE missions measured a gradual global depletion of terrestrial water storage from 2005 to 2015 of approximately 1287 gigatonnes (Gt) of water. Since water on earth is neither created nor destroyed the loss of terrestrial water is found in the seas. Seo et al found that the water loss from the land was equivalent to about 3.52 mm of global mean sea level (GMSL) rise.

It is not yet certain that the terrestrial water storage loss is linked to decadal climate variations or to longer-term changes associated with a warming climate. The certain data from the GRACE missions is not long enough the data has only been available since 2002. Since the late 1990s, there have been reports of considerable declines in evapotranspiration associated with decreasing soil moisture and increasing atmospheric vapor pressure declines. Further study is necessary to determine the cause of these observances.

Seo et al. built a predictive model to create a comprehensive analysis of how global terrestrial water storage has changed over the past four decades. Three independent datasets were integrated into the model to try to validate the soil water depletion: terrestrial water storage anomalies from Gravity Recovery and Climate Experiment (GRACE), global mean sea level from satellite altimetry, and a century-long dataset on the movement of Earth’s rotational axis  (polar motion which was found to responds to shifts in terrestrial water storage).

This work is a good start. It asks questions that will require additional GRACE data or improved models to answer. Though it tries to use other data sources to validate and understand the trend, this work is an analysis of global terrestrial water variations over the past two decades only. It is still necessary to understand the interplay of a broad range of factors that influence precipitation and the transfer of water from land to atmosphere through evaporation and transpiration. Advanced land surface and hydrological models that can accurately represent these factors under the influence of changing climate would be necessary to observe and understand the evolution of terrestrial water storage.

Developing next-generation models that incorporate anthropogenic influences such as farming, large dams, and irrigation systems (water diversions and use) is essential. The ongoing advancements of a land surface modeling system by the European Centre for Medium-Range Weather Forecasts represents a step forward. These improvements could reduce uncertainties and enhance our understanding of the impacts of climate change on the global water cycle.

Drought is Persisting

Last week the Virginia Department of Environmental Quality (DEQ), in coordination with the Virginia Drought Monitoring Task Force, has expanded the drought warning. The Drought Monitoring Task Force recommends a new Drought Watch declaration for the following regions:

• Northern Piedmont
• The entirety of the Northern Coastal Plain
• The entirety of the Shenandoah

In addition, the Drought Monitoring Task Force recommends maintaining the Drought Watch status for the following regions:

• Eastern Shore
• Northern Virginia

from DEQ

Observed 30-day precipitation shows a central swath of 0.5-1.0 inches falling along the Blue Ridge province and its borders with the Piedmont and Valley and Ridge provinces. Precipitation totals between two-to-four inches were observed in western, eastern, and southeastern portions of the Commonwealth. A small band of six-to-eight inches fell in a narrow band across the Chowan, York James, and eastern Northern Coastal Plain regions. Percent of normal precipitation during the past thirty-day period shows regions west of I-95 generally receiving less than 75% of normal precipitation.

Moisture in the top meter of soil remains largely below the 70th-percentile throughout most of the Commonwealth. Pockets of sub 20th-percentile soil moisture exist in the northern third of the State (us). Groundwater wells in northern and eastern Virginia are still primarily much below normal water levels. The Shenandoah, Northern Virginia, Northern Coastal Plain, and York James regions remain in groundwater emergency status. Wells across the Commonwealth saw limited recharge during March, and most groundwater levels remained steady or experienced some decline. Northern Virginia wells continue to exhibit sub 10th and sub 5th percentile water levels.

Daily streamflow conditions observed on April 2, 2025, showed sub 25^th percentile flow west of the Coastal Plain province, and east of the Big Sandy region. Sub 10th percentile daily flow was observed in the Upper James, Middle James, Roanoke, Shenandoah, and Northern Virginia regions. Past seven and 28-day average streamflows show widespread below-normal average streamflows across the Commonwealth. Past seven-day average streamflow conditions showing a decline in flow compared to past 28-day.

from ICPRB

The bottom line is that we are continuing in drought. According to the ICPRB,  the severity of drought continues to grow not only in Virginia but across the Potomac River watershed. The area of Severe Drought (orange) in the watershed grew from 23% two weeks ago to  30% last week, making its way west across the basin.

Rain in the Potomac Watershed over the past 30 days is 1.7 inches below normal. Winter ended at 7.6 inches of rain below normal. Since the beginning of the rain year on October 1^st we are between 54-62% of normal rainfall in Haymarket, VA. Virginia generally receives about 44 inches of precipitation per year in Prince William County, and is historically considered “water rich" area. However, droughts are not uncommon, and Virginia has a history of multi-year droughts. The graph below shows the frequency of drought years (yellow to red colors) to wet years (white) from 2000 to the present in Virginia.

from https://www.drought.gov/states/virginia

WSSC Water Quality Report

 

Every year public water suppliers are required to issue an annual drinking water quality report to their customers before July first of the following year. Last week WSSC Water released their 2024 report. WSSC Water draws the water we treat from two sources: the Patuxent and Potomac rivers. WSSC also operates 2 water filtration and treatment plants – The Patuxent (max 56 million gallons per day and the Potomac (max 285 million gallons a day) plants that together produce an average of 167 million gallons per day of safe drinking water.

WSSC Water is required to report on the water quality from these sources. WSSC Water reports that their water consistently meets all federal (US EPA Safe Drinking Water Act) and state standards. Of the 182 compounds that are required to be tested for, very few were found in the finished drinking water. Those found were in concentrations below the EPA’s maximum contaminant levels under the Safe Drinking Water Act. 

WSSC Water began quarterly monitoring for PFAS in 2020. WSSC Water proactively increased PFAS monitoring from quarterly to monthly and from 18 to 29 compounds using the latest Environmental Protection Agency (EPA) testing methods in 2022. This proactive measure goes above and beyond federal and state requirements. Test results found very low levels of PFAS in the drinking water.

In April 2024, the EPA announced the final regulation for six PFAS in drinking water, setting Maximum Contaminant Levels (MCLs) of four parts per trillion (ppt) for Perfluorooctanoic Acid (PFOA) and 4 ppt for Perfluorooctane Sulfonic Acid (PFOS), 10 ppt for PFHxS, PFNA, and HFPO-DA individually, and a Group Hazard Index for four PFAS compounds. This regulation requires additional monitoring as well as certain actions for systems above the MCLs. WSSC Water sampling results were not above the MCL.

Three emerging issues were noted in the water quality report. The first is the rising salt level in the Potomac River. The water filtration plants cannot remove salt. Sodium is a secondary contaminant in drinking water it is recommended that the level be controlled below 20 mg/L by the EPA. The reported level in the Potomac River is still below that level, but continues to rise.

The ICPRB and the Northern Virginia Regional Commission have developed a voluntary Salt Management Strategy published in 2020 to try and reduce the largest source of salt/ chloride to the Potomac, its tributaries and the Occoquan Watershed, but this alone may not slow the increasing salinization of our source water for drinking as road construction continues at an alarming pace. Even as we try to encourage the adoption of the voluntary salt management strategy, we keep building roads and paving over the counties.

Sodium and chloride the elements that make up salt and break apart in water are washed off road by rain and melting snow and flow into local waterways or seep through soils into groundwater systems with negative impacts on water quality and the environment. Salts pollute drinking water sources and are very costly to remove. The only available technology to remove salt from the source water is reverse osmosis that is expensive and requires a significant amount of energy to run. Elevated salt levels are believed to be a contributing factor to the brown water issues experienced by WSSC customers.

The water was reported to be clear leaving the water treatment plant, thus, the problem was in the distribution system. WSSC believes that the salty snowmelt and elevated sodium and chloride levels loosened the buildup of rust and manganese in their distribution system. The root cause, the failure to flush the distribution system for years, has caught up with them. Despite the appearance, WSSC reports that the water remains safe if unappealing. This is just one symptom of the problems at WSSC.

The second problem was the presence of lead. WSSC Water completed its latest triennial Lead and Copper Rule (LCR) tap sampling in 2023. Ninety percent of the homes we tested had lead levels less than the analytical reporting limit of 2.0 parts per billion (ppb) and well below the EPA’s Action Level of 15 ppb. The EPA’s new Lead and Copper Rule was formally made effective in October 2024. While WSSC Water removed all known lead pipes within their owned distribution system in the early 2000s, and the water leaving the treatment plants is lead-free, this multi-year EPA rule focuses on identifying pipe materials, including those on private property.

Lead in drinking water predominately comes from the pipes. Lead does not come from the Potomac and Patuxent. Instead, lead in drinking water is picked up from the pipes on its journey into a home or in the home itself. In the early years of public water supply the water service lines delivering water from the water main in the street into each home were commonly made of lead. This practice began to fade by the 1950’s but was legal until 1988. Lead was also used to solder copper pipes together before 1988 (when the 1986 ban on lead in paint and solder went into effect). Also, until very recently (2011 Reduction of Lead in Drinking Water Act) almost all drinking water fixtures were made from brass containing up to 8% lead, even if they were sold as "lead-free." So even homes built with PVC piping in the 2000’s may have some lead in most of the faucets.

Lead can cause damage to the brain and kidneys and can interfere with the production of red blood cells that carry oxygen to all parts of your body. The greatest risk of lead exposure is to infants, young children, and pregnant women. Scientists have linked the effects of lead on the brain with lowered IQ in children. I am amongst the many scientists who believe there is no safe level of lead exposure. If your home was built before 1990 the only way to know if you have lead in your drinking water is to test.

Property owners share the responsibility for protecting themselves and their families from lead in their home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. Before drinking tap water, flush your pipes for several minutes by running your tap. You can also use a filter certified by an American National Standards Institute accredited certifier to reduce lead in drinking water -refrigerator water filters typically have this certification.  WSSC Water has developed an inventory map where you can see the pipe material which you can find at What's Your Pipe Type? | WSSC Water

WSSC Water treats water using a corrosion inhibitor called orthophosphate to control corrosion, which was designated as the optimal corrosion control treatment by the Maryland Department of the Environment (MDE). To ensure the treatment is operating effectively, WSSC Water monitors water quality parameters set by the MDE every 6 months.

The final emerging issue is Cyanobacteria (blue-green algae). Algae blooms also called harmful algal bloom (HAB) or dead zones form in summers when higher temperatures reduce the oxygen holding capacity of the water, the air is still and especially in years of heavy rains that carry excess nutrient pollution from cities, suburban lawns and farms. The excess nutrient pollution combined with mild weather encourages the explosive growth of algae fed by excessive nutrient pollution. However, toxic algal blooms are relatively new.

In the 21st century toxic or hazardous algal blooms have become a concern in our region. They occur when algae grow out of control when there are favorable environmental conditions. Hazardous algal blooms, the ones that contain the toxins, can lead to the poisoning of fish, shellfish, birds, livestock, domestic pets and other aquatic organisms that can lead to human health impact from eating fish or shellfish exposed to toxins as well as drinking water contaminated by toxins. The existing water treatment plants do not remove the toxins and toxic algal blooms could disrupt the water supply in our region. Thus, WSSC Water monitors the reservoirs for Cyanobacteria (blue-green algae) from July to October.