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72-517: The District of Columbia Water and Sewer Authority (DC Water) provides drinking water , sewage collection, and sewage treatment for Washington, D.C. The utility also provides wholesale wastewater treatment services to several adjoining municipalities in Maryland and Virginia , and maintains more than 9,000 public fire hydrants in Washington, D.C. DC Water was founded in 1996 when

144-456: A breakdown or design fault in the sanitation system, or by chemical contaminants. Further examples of contamination include: Examples of chemical contamination include: Most water requires some treatment before use; even water from deep wells or springs. The extent of treatment depends on the source of the water. Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs. Only

216-452: A chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and arsenic can have a more immediate impact. Physical parameters affect the aesthetics and taste of the drinking water and may complicate the removal of microbial pathogens. Pesticides are also potential drinking water contaminants of the category chemical contaminants . Pesticides may be present in drinking water in low concentrations, but

288-566: A component of effective policy for health protection." In 1990, only 76 percent of the global population had access to drinking water. By 2015 that number had increased to 91 percent. In 1990, most countries in Latin America, East and South Asia, and Sub-Saharan Africa were well below 90%. In Sub-Saharan Africa, where the rates are lowest, household access ranges from 40 to 80 percent. Countries that experience violent conflict can have reductions in drinking water access: One study found that

360-523: A conflict with about 2,500 battle deaths deprives 1.8% of the population of potable water. Typically in developed countries , tap water meets drinking water quality standards , even though only a small proportion is actually consumed or used in food preparation. Other typical uses for tap water include washing, toilets, and irrigation . Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks. Globally, by 2015, 89% of people had access to water from

432-586: A farmer might plan for 35 U.S. gallons (130 L) per day for a dairy cow , a third of that for a horse , and a tenth of that for a hog . However, relatively few studies have been focused on the drinking behavior of wild animals. According to the World Health Organization's 2017 report, safe drinking water is water that "does not represent any significant risk to health over a lifetime of consumption, including different sensitivities that may occur between life stages". According to

504-421: A few large urban areas such as Christchurch , New Zealand have access to sufficiently pure water of sufficient volume that no treatment of the raw water is required. In emergency situations when conventional treatment systems have been compromised, waterborne pathogens may be killed or inactivated by boiling but this requires abundant sources of fuel, and can be very onerous on consumers, especially where it

576-548: A hardship. The WHO/ UNICEF Joint Monitoring Program (JMP) for Water Supply and Sanitation is the official United Nations mechanism tasked with monitoring progress towards the Millennium Development Goal (MDG) relating to drinking-water and sanitation (MDG 7, Target 7c), which is to: "Halve, by 2015, the proportion of people without sustainable access to safe drinking-water and basic sanitation". Washington Aqueduct The Washington Aqueduct

648-407: A hot climate, up to 16 litres (4.2 US gal) a day may be required. About 1 to 2 billion people lack safe drinking water. Water can carry vectors of disease . More people die from unsafe water than from war, then- U.N. secretary-general Ban Ki-moon said in 2010. Developing countries are most affected by unsafe drinking water. Potable water is available in almost all populated areas of

720-777: A negative effect on child development (both physical and cognitive). Sixty million people are estimated to have been poisoned by well water contaminated by excessive fluoride , which dissolved from granite rocks. The effects are particularly evident in the bone deformations of children. Similar or larger problems are anticipated in other countries including China, Uzbekistan, and Ethiopia. Although helpful for dental health in low dosage, fluoride in large amounts interferes with bone formation. Long-term consumption of water with high fluoride concentration (> 1.5 ppm F) can have serious undesirable consequences such as dental fluorosis , enamel mottle and skeletal fluorosis , bone deformities in children. Fluorosis severity depends on how much fluoride

792-521: A pumping station, A rapid sand filter plant was built at Dalecarlia Reservoir, which went online in 1927. The Dalecarlia plant is the larger of the two plants in the system, having been upgraded in the 1950s, and is the plant that serves the Virginia communities that use the Aqueduct. In 1926, Congress approved selling water from the aqueduct to Arlington County, Virginia . A new water supply pipe

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864-451: A report by UNICEF and UNESCO , Finland has the best drinking water quality in the world. Parameters for drinking water quality typically fall within three categories: microbiological, chemical, physical. Microbiological parameters include coliform bacteria , E. coli , and specific pathogenic species of bacteria (such as cholera -causing Vibrio cholerae ), viruses , and protozoan parasites . Originally, fecal contamination

936-656: A report dismissing the idea of health risks from the water. The story was picked up by The Washington Post , which ran front-page stories about the problem in January 2004. This led to a Congressional investigation, which found that the CDC had made "scientifically indefensible" claims about the lack of health effects from the lead in DC's water supply. The problem was traced to the Washington Aqueduct decision to replace

1008-482: A single pipe for water delivery, and did not have any water purification plants, relying instead on the reservoirs to act as settling basins. By the turn of the 20th century, however, Washington's growth and the high amount of sediment in the Potomac's water kept the reservoirs from doing their jobs well, and so the first treatment plant, a massive slow sand filter bed system, was installed at McMillan Reservoir, and

1080-578: A source that is suitable for drinking – called improved water source  – and 71% of the world could access safely managed drinking water that is clean and available on-demand. Estimates suggest that at least 25% of improved sources contain fecal contamination. 1.8 billion people still use an unsafe drinking water source which may be contaminated by feces . This can result in infectious diseases , such as gastroenteritis , cholera , and typhoid , among others. Reduction of waterborne diseases and development of safe water resources

1152-481: A source that is suitable for drinking – called improved water sources . In sub-Saharan Africa , access to potable water ranged from 40% to 80% of the population. Nearly 4.2 billion people worldwide had access to tap water, while another 2.4 billion had access to wells or public taps. By 2015, 5.2 billion people representing 71% of the global population used safely managed drinking water services. As of 2017, 90% of people having access to water from

1224-493: A year. Leakage of untreated and treated water from pipes reduces access to water. Leakage rates of 50% are not uncommon in urban systems. Tap water , delivered by domestic water systems refers to water piped to homes and delivered to a tap or spigot. In the United States, the typical water consumption per capita, at home, is 69.3 US gallons (262 L; 57.7 imp gal) of water per day. Of this, only 1% of

1296-517: Is WASH - standing for water, sanitation and hygiene . The WHO has investigated which proportion of death and disease worldwide can be attributed to insufficient WASH services. In their analysis they focus on the following four health outcomes: diarrhea , acute respiratory infections , malnutrition , and soil-transmitted Helminthiasis (STHs). These health outcomes are also included as an indicator for achieving Sustainable Development Goal 3 ("Good Health and Well-being"): Indicator 3.9.2 reports on

1368-419: Is atmospheric water generators . Springs are often used as sources for bottled waters . The most efficient and convenient way to transport and deliver potable water is through pipes. Plumbing can require significant capital investment. Some systems suffer high operating costs. The cost to replace the deteriorating water and sanitation infrastructure of industrialized countries may be as high as $ 200 billion

1440-436: Is a major public health goal in developing countries. In 2017, almost 22 million Americans drank from water systems that were in violation of public health standards, which could contribute to citizens developing water-borne illnesses . Safe drinking water is an environmental health concern. Bottled water is sold for public consumption in most parts of the world. Improved sources are also monitored based on whether water

1512-462: Is an aqueduct that provides the public water supply system serving Washington, D.C. , and parts of its suburbs, using water from the Potomac River . One of the first major aqueduct projects in the United States, it was commissioned by the U.S. Congress in 1852, and construction began in 1853 under the supervision of Montgomery C. Meigs and the U.S. Army Corps of Engineers . Portions of

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1584-658: Is available when needed (5.8 billion people), located on premises (5.4 billion), free from contamination (5.4 billion), and within a 30-minute round trip. While improved water sources such as protected piped water are more likely to provide safe and adequate water as they may prevent contact with human excreta, for example, this is not always the case. According to a 2014 study, approximately 25% of improved sources contained fecal contamination. The population in Australia, New Zealand, North America and Europe have achieved nearly universal basic drinking water services. Because of

1656-647: Is called desalination and is used mainly in dry areas with access to large bodies of saltwater. Publicly available treated water has historically been associated with major increases in life expectancy and improved public health . Water disinfection can greatly reduce the risks of waterborne diseases such as typhoid and cholera . Chlorination is currently the most widely used water disinfection method, although chlorine compounds can react with substances in water and produce disinfection by-products (DBP) that pose problems to human health. Local geological conditions affecting groundwater are determining factors for

1728-427: Is difficult to store boiled water in sterile conditions. Other techniques, such as filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of water-borne disease among users in low-income countries, but these suffer from the same problems as boiling methods. Another type of water treatment

1800-423: Is discharged to the Potomac is highly treated and meets some of the most stringent NPDES permit limits in the United States. Historically, wastewater treatment plants have contributed nutrients such as phosphorus and nitrogen to the waterways in which they discharge. These nutrients have been found to deplete oxygen in the marine environment, a process that is detrimental to fish and other aquatic life . Since

1872-513: Is present in the water, as well as people's diet and physical activity. Defluoridation methods include membrane-based methods, precipitation, absorption, and electrocoagulation. Natural arsenic contamination of groundwater is a global threat with 140 million people affected in 70 countries globally. Some well-known examples of water quality problems with drinking water supplies include: Water supply can get contaminated by pathogens which may originate from human excreta , for example due to

1944-787: Is responsible for all daily operations and reports to the DC Water Board of Directors. The current President/CEO is David L. Gadis. DC Water purchases drinking water from the Washington Aqueduct division of the Army Corps of Engineers. The Aqueduct sources the water from the Potomac River at Great Falls and Little Falls , north of the District. The Aqueduct treats the water, and DC Water distributes it through 1,300 miles (2,100 km) of water pipes throughout

2016-556: Is then included in the overall District of Columbia budget. Together these two budgets are presented annually to Congress for approval. When DC Water was created as an independent authority in 1996, its finances were separate from those of the District of Columbia. The independence of DC Water with regard to finance, procurement and personnel matters was affirmed by Congress under the District of Columbia Water and Sewer Authority Independence Preservation Act of 2008. A President and CEO

2088-458: Is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years. Solar water disinfection is a low-cost method of purifying water that can often be implemented with locally available materials. Unlike methods that rely on firewood , it has low impact on

2160-671: The European Drinking Water Directive and in the United States, the United States Environmental Protection Agency (EPA) establishes standards as required by the Safe Drinking Water Act . China adopted its own drinking water standard GB3838-2002 (Type II) enacted by Ministry of Environmental Protection in 2002. For countries without a legislative or administrative framework for such standards,

2232-528: The World Health Organization publishes guidelines on the standards that should be achieved. The World Health Organization considers access to safe drinking-water a basic human right. Contaminated water is estimated to result in more than half a million deaths per year. Contaminated water together with the lack of sanitation was estimated to cause about one percent of disability adjusted life years worldwide in 2010. According to

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2304-679: The chlorine used to treat the water with monochloramine , a similar chemical. Chloramine picks up lead from pipes and solder, keeping it dissolved in the water throughout the system. The Aqueduct subsequently started adding orthophosphate , a corrosion inhibitor, to the water, which reduced the extent of lead leaching from the pipes. In 2010, the CDC said that 15,000 homes in the DC area might still have water supplies with dangerous levels of lead. Drinking water The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related issues, and environmental conditions. For those who work in

2376-699: The city government and the U.S. federal government established it as an independent authority of the city's government. DC Water provides more than 600,000 residents, 16.6 million annual visitors, and 700,000 people employed in the District of Columbia with water, sewage collection, and treatment. The agency also provides wholesale wastewater treatment for 1.6 million people in Montgomery and Prince George's counties in Maryland, and Fairfax and Loudoun counties in Virginia. In 1852, Congress commissioned

2448-692: The toxicity of the chemical and the extent of human exposure are factors that are used to determine the specific health risk. Perfluorinated alkylated substances (PFAS) are a group of synthetic compounds used in a large variety of consumer products, such as food packaging , waterproof fabrics, carpeting and cookware. PFAS are known to persist in the environment and are commonly described as persistent organic pollutants . PFAS chemicals have been detected in blood, both humans and animals, worldwide, as well as in food products, water, air and soil. Animal testing studies with PFAS have shown effects on growth and development, and possibly effects on reproduction, thyroid,

2520-567: The "mortality rate attributed to unsafe water, sanitation, and lack of hygiene". Diarrhea is primarily transmitted through fecal–oral routes . In 2011, infectious diarrhea resulted in about 0.7 million deaths in children under five years old and 250 million lost school days. This equates to about 2000 child deaths per day. Children suffering from diarrhea are more vulnerable to become underweight (due to stunted growth ). This makes them more vulnerable to other diseases such as acute respiratory infections and malaria . Chronic diarrhea can have

2592-422: The 1970s a major expansion commenced that led to construction of advanced wastewater treatment components, and by 1983 the capacity was 300 mgd. In addition to Washington, the plant serves several adjacent communities in Maryland and Virginia . Drinking water and sewage treatment services were initially provided by the District of Columbia government. DC Water was established as an independent agency in 1996 by

2664-513: The Aqueduct is a 12-mile (19 km) pipeline that connects the system's dam at Great Falls with the Dalecarlia Reservoir on the border with Montgomery County, Maryland . Portions of the Aqueduct went online on January 3, 1859, and the full pipeline began operating in 1864. The pipeline runs along what is now MacArthur Boulevard , traversing some of the higher cliffs along the Potomac River. The Union Arch Bridge carries

2736-531: The Authority was found to contain lead levels of at least 1,250 parts per billion (ppb)—about 83 times higher than the accepted safe level of 15 ppb. The discovery was made by Marc Edwards , a civil engineering professor specializing in plumbing who DC Water had hired to investigate complaints of plumbing corrosion. DC Water threatened to cut off Edwards's funding unless he abandoned his investigation. The Centers for Disease Control and Prevention (CDC) released

2808-525: The District Government and the U.S. federal government. In 2010, under new leadership, the Authority underwent a rebranding effort. The rebranding included a new logo, a new color palette, and a new name. Since its inception, the Authority had been doing business as DC Water. The legal name of the agency remains the District of Columbia Water and Sewer Authority. An eleven-member Board of Directors governs DC Water. Six Board Members represent

2880-524: The District of Columbia. DC Water also manages over 1,800 miles (2,900 km) of sewer lines and operates the Blue Plains Advanced Wastewater Treatment Plant. The plant discharges to the Potomac River at the southernmost tip of the District. The National Association of Clean Water Agencies (NACWA) honored DC Water with its Research and Technology Award, given annually to member agencies who contribute to

2952-498: The District. Prince George's County and Montgomery County each have two Board Members. Fairfax County has a single Board Member. Each participating jurisdiction is a signatory to the Blue Plains Intermunicipal Agreement, which spells out the roles and responsibilities for each party and addresses facilities management, capacity allocation, and financing. The Authority develops its own budget, which

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3024-464: The NPDES permit effective September 2010, reducing nitrogen levels to 4.7 million pounds per year. DC Water plans to achieve these levels by constructing new facilities at Blue Plains to perform enhanced nitrogen removal (ENR). The total cost of the project is nearly $ 1 billion. In FY 09, the Authority rehabilitated pumping equipment and accessories in one of two stations that pump incoming wastewater into

3096-510: The WHO, the most common diseases linked with poor water quality are cholera , diarrhea , dysentery , hepatitis A , typhoid , and polio . One of the main causes for contaminated drinking water in developing countries is lack of sanitation and poor hygiene. For this reason, the quantification of the burden of disease from consuming contaminated drinking water usually looks at water, sanitation and hygiene aspects together. The acronym for this

3168-405: The aqueduct began operation on January 3, 1859, and the full pipeline began operating in 1864. The system is owned and operated by the U.S. Army Corps of Engineers and has been in continuous use ever since. It is listed as a National Historic Landmark . The Union Arch Bridge , which carries a portion of the aqueduct, is also listed as a Historic Civil Engineering Landmark . The centerpiece of

3240-583: The capacity of the pipe. To prevent sewer backups and flooded streets, these combined sewers may discharge into the Anacostia and Potomac Rivers and Rock Creek , a phenomenon known as combined sewer overflows (CSOs). To date, DC Water has significantly reduced CSOs by eliminating approximately 40 percent of the overflows through a $ 140 million construction and mitigation program. This investment included inflatable dams to catch and store overflows during rainstorms, tide gates to keep river water from flowing into

3312-463: The construction of an aqueduct system to provide a reliable supply of drinking water to the city from the Potomac River . The US Army Corps of Engineers designed and built the Washington Aqueduct , which began full operation in 1864. Filtration plants were added to the system in the 20th century. In 1938, the District of Columbia built a sewage treatment plant in the Blue Plains area, at

3384-415: The cost of delivery of water and sewer service. A little more than half of the rates cover operations. Another quarter covers the cost of capital projects like replacement of aging water and sewer lines, valve replacements, and pump station improvements. Capital projects also include several projects designed to protect the environment and are required by the U.S. Environmental Protection Agency (EPA). Though

3456-404: The environment. In many areas, low concentration of fluoride (< 1.0 ppm F) is intentionally added to tap water to improve dental health , although in some communities water fluoridation remains a controversial issue. (See water fluoridation controversy ). According to the World Health Organization (WHO), "access to safe drinking-water is essential to health, a basic human right and

3528-463: The field of biosolids usage and disposal or wastewater treatment. The research project must be completed in-house (or by a contractor working directly with the agency). It must relate to the collection process, treatment process, or reuse of wastewater. This innovation by the DC Water team has a global impact in protecting aquatic life in waterways that receive wastewater discharges. The year 2010 marks

3600-535: The high initial investments, many less wealthy nations cannot afford to develop or sustain appropriate infrastructure, and as a consequence people in these areas may spend a correspondingly higher fraction of their income on water. 2003 statistics from El Salvador, for example, indicate that the poorest 20% of households spend more than 10% of their total income on water. In the United Kingdom, authorities define spending of more than 3% of one's income on water as

3672-400: The highest grade of B+, and others scored as low as Cs and even Ds. The District of Columbia is one of 772 older cities in the country with a combined sewer system. The system covers about a third of the city and was built in the late 19th century to carry sanitary sewage and stormwater in the same pipe. The system operates well in dry weather. However, during rainstorms, the flow can exceed

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3744-402: The immune system and liver. As of 2022 the health impacts of many PFAS compounds are not understood. Scientists are conducting research to determine the extent and severity of impacts from PFAS on human health. PFAS have been widely detected in drinking water worldwide and regulations have been developed, or are under development, in many countries. Drinking water quality standards describes

3816-536: The mandate comes from the federal government, the funding sources for these construction projects are not identified. While a small amount of funding has come through the Clean Water Act and Safe Drinking Water Act and other grants, the majority of these capital costs are borne by the ratepayers. At Blue Plains, wastewater treatment goes beyond primary and secondary treatment levels to tertiary (or advanced) treatment . The effluent that leaves Blue Plains and

3888-420: The matter is resolved. The ability of point of use (POU) options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest. The current priority of the proponents of POU treatment

3960-675: The mid-1980s, Blue Plains has reduced phosphorus to the limit of technology, primarily in support of water quality goals of the Potomac River, but also for the restoration of the Chesapeake Bay . The Chesapeake Bay Agreement, reached in 1987, was a first step in reducing nitrogen discharge to waterways that are tributary to the Chesapeake Bay. Under the agreement, the Bay states and the District committed to voluntarily reduce nitrogen loads by 40 percent from their 1985 levels. Blue Plains

4032-592: The nitrification/denitrification process and aims to meet the nitrogen reduction goals of the Chesapeake Bay Program. It will also increase energy efficiency. On the waterways, the Authority operates two skimmer boats that remove floatable debris from the Anacostia and Potomac rivers every Monday through Friday. These crews remove more than 400 tons of trash from our waterways each year. Plastic bottles, plastic bags, inflatable toys, baseballs, and environmental debris like tree limbs, are all skimmed from

4104-623: The pipeline and MacArthur Boulevard over Cabin John Creek and the Cabin John Parkway near the community of Cabin John, Maryland . This bridge was the longest masonry arch bridge in the world for 40 years. The Dalecarlia Reservoir serves as a primary sedimentation basin. A portion of the water from the reservoir is treated at the nearby Dalecarlia Water Treatment Plant and distributed to municipal water mains. The remainder of

4176-549: The plant and replaced aged infrastructure and equipment in the plant's final filters with a more effective system. All the upgrade projects were tied into the plant-wide process control system (PCS), which monitors and controls the plant's processes from a central location. Progress was achieved by implementing the nitrification/denitrification facilities upgrade to convert nitrification reactors from coarse to fine bubble diffusion and modify structures equipment. The rehabilitated and new equipment will support other ongoing upgrades to

4248-487: The presence of various metal ions , often rendering the water " soft " or " hard ". In the event of contamination of drinking water, government officials typically issue an advisory regarding water consumption. In the case of biological contamination , residents are usually advised to boil their water before consumption or to use bottled water as an alternative. In the case of chemical contamination , residents may be advised to refrain from consuming tap water entirely until

4320-443: The quality parameters set for drinking water. Water may contain many harmful constituents , yet there are no universally recognized and accepted international standards for drinking water. Even where standards do exist, the permitted concentration of individual constituents may vary by as much as ten times from one set of standards to another. Many countries specify standards to be applied in their own country. In Europe, this includes

4392-519: The second consecutive year that DC Water has been recognized with this award. In 2010, DC Water received from NACWA the Platinum Peak Performance Award after receiving five consecutive Gold Awards for 100 percent compliance with permit limits. This award is presented to member agencies for exceptional compliance for their National Pollutant Discharge Elimination System (NPDES) permit limits. Rates paid by ratepayers cover

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4464-583: The sewer system, sewer separation to eliminate CSO outfalls, and pumping station construction and rehabilitation to increase flow capacity. In 2013 the agency began construction of a deep tunnel system for its "Clean Rivers Project." The $ 2.4 billion, 20-year project will reduce CSOs by 96 percent overall and 98 percent in the Anacostia River. Once operational, the tunnel system will store the combined sewage during wet weather and release it gradually for treatment at Blue Plains. In 2001, water supplied by

4536-555: The southernmost tip of DC. The cost was $ 4 million. The plant was built to stop raw sewage from entering the Potomac and Anacostia Rivers . At that time, the plant was built to treat sewage from a population of 650,000, with a capacity of 100 million gallons per day (mgd). By 1943, the population grew to 1.5 million people, contributing much more sewage, and upgrades to the plant were necessary. Secondary treatment units were added in 1959, with an expanded discharge capacity of 240 mgd. In

4608-739: The water from the reservoir flows to the Georgetown Reservoir in the Palisades neighborhood of Washington. This facility serves as an additional sedimentation basin, and then the water flows through the Washington City Tunnel to the treatment facility at the McMillan Reservoir , after which it is pumped through city mains. The Dalecarlia Reservoir was modified in 1895 and 1935 to improve water quality and increase water supply. The system originally used

4680-437: The water provided by public water suppliers is for drinking and cooking. Uses include (in decreasing order) toilets, washing machines, showers, baths, faucets, and leaks. As of 2015, American households use an average of 300 gallons of water a day. The qualitative and quantitative aspects of drinking water requirements on domesticated animals are studied and described within the context of animal husbandry . For example,

4752-403: The waterways and deposited into oversized dumpsters for removal. In decades past, there used to be more oversized items, such as sofas and refrigerators. However, over the years, the skimmer boats have removed most of those. Still, there is the occasional unlikely item, such as the live deer that was recently rescued to dry ground. In addition to their full-time work assignments, these crews clean

4824-497: The way for special events like the Nation's Triathlon and high school crew competitions, as well as for conservation efforts. As a result of the work DC Water contributes, "The District, as a city, is head and shoulders above any other municipality in the Bay watershed," said Tom Schueler of the nonprofit Chesapeake Stormwater Network. In 2009, The Stormwater Network developed a stormwater performance grading scale. The District received

4896-480: The world, although it may be expensive, and the supply may not always be sustainable. Sources where drinking water is commonly obtained include springs , hyporheic zones and aquifers ( groundwater ), from rainwater harvesting , surface water (from rivers, streams, glaciers ), or desalinated seawater . For these water sources to be consumed safely, they must receive adequate water treatment and meet drinking water quality standards . An experimental source

4968-519: Was completed in 1905. Improvements in the early 1900s were planned and supervised by Army engineer Henry C. Newcomer . The regular use of chlorine as a disinfectant began in 1923 at the McMillan plant. The McMillan plant was not replaced until 1985, when a rapid sand filter plant was opened next to it. In the 1920s, the aqueduct was upgraded with the addition of a second pipe from Great Falls to Dalecarlia, along with several new reservoirs and

5040-523: Was constructed at Chain Bridge and service to Arlington began in 1927. Additional pipes were built as Arlington's population grew, including one under the Potomac River. In 1947, Congress approved adding the city of Falls Church, Virginia , to the aqueduct system, and nearby portions of Fairfax County, Virginia , were added in the 1960s. The U.S. Army Corps of Engineers built an additional intake and pumping station at Little Falls in 1959. The Aqueduct

5112-658: Was determined with the presence of coliform bacteria , a convenient marker for a class of harmful fecal pathogens . The presence of fecal coliforms (like E. Coli ) serves as an indication of contamination by sewage . Additional contaminants include protozoan oocysts such as Cryptosporidium sp. , Giardia lamblia , Legionella , and viruses (enteric). Microbial pathogenic parameters are typically of greatest concern because of their immediate health risk. Physical and chemical parameters include heavy metals , trace organic compounds , total suspended solids , and turbidity . Chemical parameters tend to pose more of

5184-568: Was the first plant to achieve that goal. Furthermore, every year since the full-scale implementation of the Biological Nitrogen Removal (BNR) process was completed in 2000, Blue Plains has every year successfully achieved and exceeded that goal of a 40 percent reduction. In Fiscal Year 2009, the BNR process at Blue Plains reduced the nitrogen load by more than 58 percent. DC Water and EPA agreed upon new nitrogen limits as part of

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