Pesticide Contamination in the Potomac Watershed

Samuel A. Miller, Kaycee E. Faunce, Larry B. Barber, Jacob A. Fleck, Daniel W. Burns, Jeramy R. Jasmann, Michelle L. Hladik, Factors contributing to pesticide contamination in riverine systems: The role of wastewater and landscape sources, Science of The Total Environment, Volume 954,2024, 174939, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2024.174939.

The article below is excerpted from the research article cited above.

The Potomac River Watershed is the second largest watershed (36,750 km²) within the Chesapeake Bay watershed and contributes about 15 % of the total streamflow to the Bay. The mainstem of the Potomac River has minimal flow regulation and is freshwater and the major source of drinking water for the  Washington, D.C. metropolitan area- Loudoun Water, Fairfax Water, Leesburg Water, WSSC and the Washington Aqueduct.

 Population in the Potomac River Watershed more than doubled from 1970 (3.2 million) to 2020 (6.9 million). The majority of development during this period occurred in the Washington, D.C. metropolitan area, where about 84 % of the watershed’s population resided as of 2020. To accommodate population growth, forest and agricultural lands have been reduced and public water supply and wastewater treatment systems have been expanded drawing on the Potomac River itself. A majority of public-supply withdrawals (80 %) in the Potomac River Watershed are from surface water.

The Potomac River Watershed contains a varied landscape consisting of steep mountains, rolling hills, broad valleys, and plains. The majority (53 %) of the basin is forested, 23 % is agricultural, and 13 % is developed whereas smaller remaining portions contain water, wetlands, and barren land cover. 

According to Miller et al wastewater discharges, although treated and in compliance with existing regulations, can be a continuous source of organic contaminants, including pesticides, to the Potomac River and  rivers worldwide. Pesticides can be introduced to wastewater treatment plants by what goes down-the-drain or flushed down the toilet at homes and businesses. Urban and suburban stormwater enter the watershed and may include sources of pesticides from residential lawns and gardens, leaky septic systems, or outdoor pest control, including applications to impervious surfaces. Separate sanitary sewer systems can also contain water sourced from groundwater via infiltration through cracked or broken sewerage pipes.

Frequently, pesticides are transformed or not completely removed during conventional wastewater treatment which are not designed to address these contaminants and are discharged in the wastewater treatment plant effluent to receiving waterbodies. In addition, some wastewater treatment plants receive industrial discharges. Although pesticides are frequently introduced to aquatic environments from agricultural and developed land-use nonpoint sources, wastewater treatment plant-derived pesticides are of particular concern because they are continuously discharged to receiving waters that often serve as source water for drinking water plants. Discharge from the largest wastewater treatment plant in the study area, UOSA,  is one of the largest indirect potable water reuse sources in the world (Jeffrey et al., 2022).

An integrated model was developed for the Potomac River watershed to determine the amount of accumulated wastewater percentage of streamflow and calculate predicted environmental concentrations (PECs) for 14 pesticides in non-tidal National Hydrography Dataset Plus Version 2.1 stream segments. Model predicted environmental concentrations were compared to measured environmental concentrations from 32 stream sites that represented a range of land use to evaluate model performance and to assess possible non-WWTP loading sources. Statistical agreement between PECs and MECs was moderate- it was strongest for insecticides, followed by fungicides and herbicides.

Among the target pesticides, PECs generally had the best agreement with MECs (Fig. 6) for insecticides (ρ = 0.52, p < 0.01), followed by fungicides (ρ = 0.36, p < 0.01) and herbicides (ρ = 0.20, p = 0.14). Individual pesticides with significant correlations between PECs and MECs included dinotefuran (ρ = 0.87, p < 0.01), thiabendazole (ρ = 0.82, p < 0.01), fipronil (ρ = 0.61, p < 0.01), and tebuconazole (ρ = 0.53, p = 0.02). Significant correlations were found between these individual pesticide concentrations and water quality indicators of wastewater presence including the optical brightener-to-fluorescein ratio, and boron concentrations, confirming that wastewater treatment plants effluent likely is a source for these pesticides.

Target pesticide corrected-MECs that had the most significant correlation with estimated agricultural use included atrazine (ρ = 0.54, p < 0.01), clothianidin (ρ = 0.35, p = 0.05), metolachlor (ρ = 0.62, p < 0.01), and simazine (ρ = 0.70, p < 0.01). The lack of agreement between corrected-MECs and estimated pesticide use on agricultural land for the remaining target pesticides indicates there may be sources beyond wastewater treatment plant effluent and agriculture during stream base flow conditions.

Pesticides are commonly used within the Potomac River Watershed for non-agricultural purposes, such as: (1) maintenance of lawns, gardens, and golf courses, (2) defoliation of rights-of-way, and (3) structural pest control (Ator et al., 1998). Pesticide usage rates are not well documented for these categories, which makes source identification difficult.

The U.S. Environmental Protection Agency estimated in 2012 that more money was spent on insecticides used in home and gardens ($2,650,000,000) than in agriculture ($1,499,000,000) and industry ($700,000,000) combined, and overall, 27 million kilograms of pesticides were applied to home and garden areas (Atwood and Paisley-Jones, 2017). Homeowners frequently apply high rates of pesticides beyond the recommended doses that unintentionally leave residues that pose a variety of human and ecological health threats (Md Meftaul et al., 2020).

Water-quality samples were collected from 32 streams within the Potomac River Watershed during low-flow conditions to represent periods with the greatest effects from ACCWW and legacy pesticide sources. In the study watersheds,  turfgrass percentage of drainage area was found to be significantly correlated with all target fungicides, insecticides, and diuron. This study did not assess variability in results over time, which may be important at some sites based on local conditions. At best this model could be used as a screening tool and not much more.

Inland Flooding

The past few weeks we’ve seen lots of flooding across the southeast, devasting flooding in North Carolina and Georgia and massive storm surge from the two recent hurricanes-Helena and Milton. Tampa and the western cost of Florida suffered a double hit.

There have always been great storms. The Pittsburgh St Patrick’s day flood in 1936 and the flooding that hit the northeast in 1987, but our Climate is changing, too. Locally (here in Prince William County Virginia), rainfall averages approximately 44 inches per year, but varies from year to year.  Climate forecasts are for our region to get wetter with more intense rainstorms and droughts to get more severe. (ICPRB). The relationship between climate change and flooding is complex. Shoreline flooding is the result of land subsidence, sea level rise, building in the flood plain and storm surge. The most well-established connection between climate change and inland flooding is that more warming leads to more intense rainfall, which in turn increases flood severity in the inland areas. 

This rainfall intensification effect reportedly accounts for more than one-third of all damages from inland flooding in the U.S. in recent decades. Changes in land use are also intensifying inland flooding. Land use changes that increase impervious cover reduces the open area for rain and snow to seep into the ground and percolate into the groundwater and the impervious surfaces cause stormwater velocity to increase preventing water from having enough time to percolate into the earth, increasing storm flooding. 

 Increased stormwater volumes and mud flow are a direct result of clearing the land of trees and vegetation, construction activities for buildings and roads. The devastating flooding we’ve seen in North Carolina’s inland mountain towns that are thousands of feet in elevation and hundreds of miles from any coastline seemed so unexpected (despite major floods and landslides in that area -in 1916, tropical storms that originated in Mississippi and South Carolina caused unprecedented flooding in the Asheville area killing around 80 people and causing massive damage. Back-to-back tropical storms hit the region in 2004. Which resulted in flooding.  Helene inundated parts of southern Appalachia with well over 2 feet of rain. Floodwater carried away entire houses and washed out highways, cutting off access to towns some that are still cut off. 

Prince William County has committed to preparing for the impacts of climate change as part of our goal of becoming a Climate Ready Region by 2030. In line with this commitment, the county staff has concentrated on understanding the susceptibility of our county's people and infrastructure to local climate hazards to meet the community's most pressing needs. The county completed a vulnerability assessment in January 2023. This evaluation was designed to anticipate future conditions that could amplify existing vulnerabilities. From 2018 to 2021 Prince William County has had 60 reported Swift Water Rescue events and 178 reported VDOT road closures due to intense precipitation and flooding. Locations of these events are shown below and are mostly inland events. Though the eastern edge of our county is shoreline. This was unexpected. Prince William County realized that they need detailed stormwater modeling  to better understand how flooding occurs throughout the County during precipitation events and to better understand the limitations of existing stormwater infrastructure.  

from PWC

 In the research paper cited below: “The Northeastern United States (which includes Prince William County in their study) has experienced …increases in extreme precipitation events over the past five decades (Melillo et al., 2014, Walsh and Coauthors, 2014, Parr and Wang, 2015a). While the intensities of the most extreme precipitation events (or the heaviest 1% of all daily events) have increased in every region of the contiguous United States since the 1950s, the maximum change in precipitation intensity of extreme events is occurring in the northeast. “ The models used in the study found that that trend is likely to continue for decades.

The results of this study indicate an increase in mean (20–25%) and extreme (>40%) precipitation in near future over the northeast (including the Potomac River basin). In addition, water depths resulting from extreme inland flooding may increase more than 100% in some regions. Neighborhood scale projections suggest that the major cities of the northeast and the surrounding areas will likely be at higher flood risk. In turn, extreme precipitation and flooding can pose significant risks to their infrastructures and networks. It is time to focus on climate adaptation. Even as close as we are to the federal government, we may still find that we are on our own in a flooding disaster.

 

from Sujan et al

Sujan Pal, Jiali Wang, Jeremy Feinstein, Eugene Yan, Veerabhadra Rao Kotamarthi, Projected changes in extreme streamflow and inland flooding in the mid-21st century over Northeastern United States using ensemble WRF-Hydro simulations, Journal of Hydrology: Regional Studies, Volume 47, 2023, 101371, ISSN 2214-5818, https://doi.org/10.1016/j.ejrh.2023.101371

Pay For Actual Pollution Reductions

If you recall, in 2010 the EPA set a limit for release of nutrients and sediment into the Chesapeake Bay watershed that was then partitioned to the six  states (and Washington DC) watershed based on the Chesapeake Bay computer model and monitoring data. Likeall government programs it will never die, but continually evolve and grow.

All six Bay watershed states and the District of Columbia were required to submit plans spelling out the measures each would take by 2025 to achieve the needed pollution reductions. Then each year, EPA would evaluate the progress in implementing mitigation measures or practices. The model then would be used to estimate the amount of nitrogen, phosphorus and sediment that would make it to the Bay under average conditions.

Only the District of Columbia and West Virginia have so far met their 2025 goals. The rest of us continue to struggle to implement all the measures outlined in our plans. The goal was to have all the practices in place by 2025 to meet the Chesapeake Bay Clean Water Blueprint restoration goals as predicted by the computer model forecasts.

Virginia continues to lag behind its goals. Virginia achieved its 2023 nitrogen targets for the James basin but did not achieve its 2023 targets for nitrogen in the other major basins (Potomac, Rappahannock, York, and Eastern Shore). Virginia did not achieve its 2023 phosphorus targets for any major basin.  In their “suggestions for improvement” EPA recommended that Virginia target implementation of nonpoint sources of pollution in the urban/suburban stormwater sector and the agricultural sector using the cost share BMP implementation programs.

As Virginia struggles to meet our 2025 Chesapeake Bay clean up goals, DEQ has announced a new $20 million Pay-For-Outcomes Nonpoint Source Pollution Reduction grant program. This is similar to a program that Maryland adopted last year. This one-year pilot program will provide payments based on the number of pounds of pollution actually removed or prevented.

DEQ intends that the Pay-For-Outcomes program will reverse the script and identify the most cost-effective means of reducing nonpoint source pollution and encourage innovation. All this is intended to move us forward in the Chesapeake Bay cleanup. The truth is, thought the Ag BMP modeling is backed by scientific calculations, there isn’t a full verification to guarantee water quality is improving after a practice is installed. The cleanup is further challenged by all the land use changes as the region continues to develop urban and industrial sprawl of higher density housing and data centers.

Under the DEQ Pay-For Outcomes program, any business, nonprofit, government entity, or individual may apply for grants ranging from $100,000 to $7.5 million to reduce the amount of nitrogen and phosphorus pollution entering Virginia’s Chesapeake Bay watershed. The proposals may rely on Best Management Practices already commonly used in Virginia or may offer novel technologies based on sound science.

The applicants will need to identify the price per pound of pollution that will reduced, and payments will be based on the actual reductions. A panel of professors chosen as scientific experts will review the proposals and rank each primarily on cost per pound of pollution reduction but with consideration to habitat and resilience benefits, readiness to proceed, and other factors.

Applications are due Feb. 3, 2025. A mandatorypre-application webinar will be held on January 6, 2025. Stay tuned for furtherinformation.

Cats in Hats Pain Study

Aliénor Delsart, Aude Castel, Guillaume Dumas, Colombe Otis, Mathieu Lachance, Maude Barbeau-Grégoire, Bertrand Lussier, Franck Péron, Marc Hébert, Nicolas Lapointe, Maxim Moreau, Johanne Martel-Pelletier, Jean-Pierre Pelletier, Eric Troncy, Non-invasive electroencephalography in awake cats: Feasibility and application to sensory processing in chronic pain, Journal of Neuroscience Methods, Volume 411, 2024, 110254, ISSN 0165-0270, https://doi.org/10.1016/j.jneumeth.2024.110254.

The following was excerpted from the article cited above and the press release.

When being tested for chronic pain from common conditions like osteoarthritis, awake cats tend to shake off and chew the wired electrodes placed on their heads to produce electroencephalograms (EEGs). Scientists at the Veterinary School of the Université de Montréal have found a way to scan the brains of cats while they’re awake, using electrodes attached under specially knitted wool caps (and apparently a sweater).

Feline osteoarthritis leads to chronic pain. In humans, sensory exposure can modulate chronic pain. The scientists were interested in determining if that might work in cats.  In recent studies of human pain using electroencephalography (EEG) revealed a specific brain signature for human osteoarthritis. However, EEG pain characterization or its modulation did not exist in cats, because all EEG were conducted in sedated cats, using intradermal electrodes, which could alter sensory (pain) perception.

 To overcome cat rejection of the electrodes, a wool hat was specially made for the study. The hat is described as knitted in the press release, but looks like it may be crocheted in a couple of the pictures.  The little cap held the electrodes in place even during cat movements. One of the graduate students was able to make the caps. For anyone who is interested in this there are several YouTube videos, and the “Cats in Hats” pattern book can be found on amazon patterns are also available on Etsy. Yes, I once actually knitted little kitty hats as part of Halloween outfits for my cats. Only one of my cats was happy to wear it, but she was perfectly content to do so.  

EEG evaluations of lights and scents impact on pain were performed in conscious cats, in a quiet and dim-lighted). Ten gold-plated surface electrodes were placed without shaving the hair under the caps. After assessing their stress and pain through stimuli passed through the electrodes, the scientists then went about exposing the cats to soothing stimuli such as colored lights and comforting smells, to ease their suffering.

This is the first successful use of EEGs in conscious cats with surface electrodes recording brain activity while exposing them to sensory stimulations. Though they seemingly did not find lights or scents that would ease pain, the scientists felt this work opens new avenues for investigating feline chronic pain and its potential modulation through sensory interventions. No doubt, further work will discover that a heating pad reduces the pain. I am just guessing that based on the five cats that have been part of our family over the years. Though I poke gentle fun at the research, I welcome this work because there have been several times over the decades that I wanted to know if a cat was in pain, and what they were feeling.

The study was approved by the Institutional Animal Care and Use Committee. The care and handling of all cats adhered to the Canadian Council on Animal Care’s guidelines. Adult neutered cats (n=11 (6 females); [3–16] years) with naturally occurring OA were enrolled in the study. Cats were selected based on their behavioral compliance- willingness to wear hats and lie still in while staying awake. 

 This study was partially funded by the Morris Animal Foundation (A.CA. & E.TR.). This work was sponsored, in part, by Discovery grants, a Collaborative Research and Development grant, as well as by an ongoing New Opportunities Fund grant , a Leader Opportunity Fund grant and a series of research groups.

 

Economic Impacts on DMV from Water Supply Disruption

 

Below is excerpted from the press release, the entire press conference and report are linked below:

Last week, the Interstate Commission on the Potomac River Basin (ICPRB) released a new report highlighting the significant and dire financial consequences facing the Washington, D.C., region in the event of a disruption to the area’s water supply.

In just one month, a significant disruption from threats like infrastructure failures or natural disasters in D.C. region’s water supply could result in a loss of $15 billion in gross regional product (GRP) and hundreds of millions in tax losses, according to the report, “The Economic and Fiscal Costs of Water Supply Disruption to the National Capital Region.”

“The Potomac River is the single source of drinking water for Washington  D.C. and provides water for roughly five million people in the region,” said ICPRB Executive Director Michael Nardolilli. “It is integral to the functioning of the nation’s capital. This report clearly shows that any disruption to the water supply would have catastrophic economic consequences for the region, especially for the most vulnerable residents of our nation’s capital. Securing the resilience of our water infrastructure is not just a priority, it’s a necessity.”

“The interconnectedness of our region means that water supply disruptions would have far-reaching consequences affecting the District of Columbia as well as our neighboring communities in Virginia and Maryland,” said COG Board Chair and District of Columbia Councilmember Charles Allen. “This report underscores the importance of regional collaboration in safeguarding our water resources and why COG is working with our partners to ensure a backup water source for the region.”

“DC Water’s motto, ‘Water is life,’ reflects how seriously we, as the water authority for the nation’s capital, take our role in supplying our customers with abundant, safe and reliable water,” said David L. Gadis, Chief Executive Officer (CEO) and General Manager of DC Water. “Resilience in the water sector, one of DC Water’s five strategic imperatives, is crucial not only for our success, but also for the health and wellbeing of the customers who depend on DC Water. This water supply vulnerability must be addressed to protect our city now and for the future generations to come.”

“Our region’s economic vitality and quality of life are directly tied to clean, reliable water resources,” said Jack McDougle, President and CEO of the Greater Washington Board of Trade. “This report highlights that a disruption in the water supply would not only harm the local economy but also have a disproportionate impact on the diverse business sectors and people who contribute to the vibrancy of our nation’s capital the Greater Washington region. This includes small, minority-owned, women-owned, and veteran-owned enterprises, which are at greater risk of permanent closure if forced to shut down due to water supply disruptions. It is imperative that we confront this challenge proactively to safeguard our thriving region and everything it has to offer.”

“Federal investment in our nation’s water infrastructure is essential to protect all communities from the devastating impacts infrastructure failures can have on operations,” said Mae Stevens, CEO of the American Business Water Coalition. “Restoring the country’s water systems to meet the needs of the population is expected to cost more than $1.25 trillion over the next 20 years, a figure far too large for utilities, companies and private citizens to meet alone. Congress needs to recognize this as a critical need and close the funding gap so that we can better protect the D.C. region and our nation against devastating water supply disruptions.”

Yet every time the federal government has funded infrastructure with massive programs, we have short changed water and sewer infrastructure, instead funding programs less critical to our survival than water availability.

Key findings presented in the report include:

• Economic impact: The report estimates that a significant water supply disruption could result in losses of almost $15 billion in gross regional product (GRP) and hundreds of millions in tax losses, all within the first month.
• Disproportionate impact: Small, women-owned and minority-owned businesses are particularly vulnerable to the effects of water supply disruption, with potential losses that could devastate their operations and subsequently, impact the livelihoods of their employees. Supply disruption would additionally have a greater impact on lower-income households that have fewer financial resources to mitigate the loss of services.
• Sectoral vulnerability: Major sectors, including healthcare, food and beverage, chemical manufacturing and arts & entertainment, are identified as being at severe risk, underscoring the necessity for enhanced infrastructure resilience and preparedness.

The report’s sponsors including the regional water companies, called for Congressional action to fund crucial infrastructure projects to ensure greater resiliency in the D.C. region’s water supply and safeguard the health and safety of both the public and the economy. 

Fairfax Water Qauality

 

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. In June Fairfax Water released their report which can be found in its entirety at this link.  Fairfax Water owns and operates the James J. Corbalis Jr. and the Frederick P. Griffith Jr. treatment plants. These plants are the primary source of water for most of Fairfax County and portions of Loudoun County and Prince William County. Fairfax Water acquired the City of Falls Church water distribution system as well as an area that serves approximately 120,000 people and obtain their water from the Dalecarlia and McMillan treatment plants, part of the Washington Aqueduct which is owned and operated by the U.S. Army Corps of Engineers.

The result is that now Fairfax Water provides water to county residents from their two water treatment plants and buys water from the Washington Aqueduct to supply residents in and around the City of Falls Church. These were historic systems that were once town owned. The newer developments around Merrifield and the Dunn Loring Metro Station are supplied water from the Fairfax Water owned plants. Thus, they are required to report on the water quality of all these sources. 

Both the Washington Aqueduct and Fairfax Water run excellent water treatment plants. All four plants use advanced technologies and practices in drinking-water treatment, which is the process of cleaning raw water to make it safe to drink. Fairfax Water reports that their water consistently surpasses 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 well below the EPA’s maximum contaminant levels under the Safe Drinking Water Act. Fairfax Water’s state-certified Water Quality Laboratory performs or manages the testing required by federal and state regulations. The Washington Aqueduct does the testing for the water they supply. 

Two issues emerged from the review of the water quality report. The first is the rising salt level in the Occoquan Reservoir and from the Potomac River. From comparing the Washington Aqueduct numbers to the Fairfax Water numbers it is clear that the Occoquan Reservoir has a higher level of salinity than the Potomac River, but both levels are rising. Sodium is a secondary contaminant in drinking water it is recommended that the level be controlled below 20 mg/L by the EPA.

The ICPRB, the Virginia Department of Environmental Quality (VDEQ) 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. 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 which could cost Fairfax Water alone $1-2 billion to install and requires a significant amount of energy to run. 

The second problem that was seen in the water quality report was the presence of PFAS above the target regulatory level. In April 2024, the EPA announced the final national primary drinking water standards for six poly- and perfluoroalkyl substances (PFAS). Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed the maximum contaminant levels (MCLs). Fairfax Water has stated that they will ensure their water meets these standards by the regulatory date.

Even with these issues, the quality of the finished drinking water being produced at Washington Aqueduct and Fairfax Water meets or exceeds all United States Environmental Protection Agency (US EPA) current standards and requirements. The water quality report released in June covers the sampling done during calendar year 2023. There were no violations of the U.S. EPA’s Safe Drinking Water Act.

Water Rates

Water bills in our region have been increasing, but imagine my surprise when I saw the regional water rates posted by Fairfax Water .  At first glance the water rates appeared to have gone down, but like many things instead had suffered shrinkflation. The amount of water in the standard quarterly bill was reduced from 18,000 gallons to 15,000 gallons. So, rates indeed went up again. Manassas Park has reclaimed its title of most expensive water in the region grabbing it back from the Town of Leesburg.

There is no true “cost” of water, the price charged for water, often does not reflect its value or true cost.  Recently, Fairfax Water announced its intention to raise their water rates next spring as they do almost every winter. There will be, as usual, a public hearing on Thursday, December 12, 2024, on the proposed rate increase held at Fairfax Water’s main office at 8570 Executive Park Avenue in Fairfax. This rate increase is part of their ongoing program to ensure that the water infrastructure in Fairfax County is maintained. The proposed rate increase will go into effect April 1, 2025. Visit Fairfaxwater.org/rates for a complete list of rate and fee increases.

The need for infrastructure replacement is an issue that has caused significant service problems and rate increases in other parts of the Washington Metropolitan region. Fairfax Water Board of Directors have dedicated funding to infrastructure maintenance and replacement for many years and has forecast future capital needs for replacing water mains in the system. The Town of Leesburg did not have a capital program in place. 

Every time they propose to raise water rates, Fairfax Water performs a comparison of the water costs throughout the Washington Metropolitan region. I have tracked this information over the years, and was shocked to see rates decrease this year, until I read the footnote. The comparison of rates as of July 2017, 2018, 2019, 2022, and 2023 was base on a quarterly use of 18,000 gallons of residential water . In 2024 Fairfax Water choose to change the quantity of water used for the comparison to 15,000. This will not only appear to reduce rates but might also change the excess charges. I adjusted up the rates by 120% to make them more or less comparable to previous years. Fairfax Water’s rate has returned to the lowest in the Washington metropolitan region, but they choose the comparison rules.  Fairfax Water sells water to Prince William Service Authority, American Water, Manassas Park and others.