Drinking Water Legislation
Almost any legislation concerning water affects drinking water, either directly or indirectly. The following pieces of legislation are aimed specifically at providing safe drinking water for the nation's residents.
SAFE DRINKING WATER ACT OF 1974.
The SDWA mandated that the EPA establish and enforce minimum national drinking water standards for all public water systems—community and noncommunity—in the United States. The law also required the EPA to develop guidelines for water treatment and to set testing, monitoring, and reporting requirements.
To address pollution of surface water supplies to public systems, the EPA established a permit system requiring any facility that discharges contaminants directly into surface waters (lakes and rivers) to apply for a permit to discharge a set amount of materials—and that amount only. It also created groundwater regulations to govern underground injection of wastes.
Congress intended that, after the EPA had set regulatory standards, each state would run its own drinking water program. Since 1974, 54 states and territories have been granted "primacy"; that is, they have been given the primary responsibility for enforcing the requirements of the SDWA. In order to be granted primacy a state must adopt drinking water standards at least as stringent as the national standards (those established by the EPA), and it must be able to conduct monitoring and enforcement programs that meet federal standards.
The EPA established the Primary Drinking Water Standards by setting maximum containment levels (MCLs) for contaminants known to be detrimental to human health. All public water systems in the United States are required to meet primary standards. Secondary standards cover non-health-threatening aspects of drinking water such as odor, taste, staining properties, and color. Secondary standards are recommended but not required.
SOLE-SOURCE AQUIFERS.
Under the SDWA, the EPA has the authority to designate certain groundwater supplies as the sole source of drinking water for a community (referred to as "sole-source aquifers") and to determine if federal financially assisted projects may contaminate these aquifers. If the EPA determines that contamination could occur, no commitment of federal financial assistance—such as grants, contracts, loan guarantees, and so on—can be made for that project.
As of April 2004 the EPA had designated 73 sole-source aquifers nationwide. To be designated as a sole-source aquifer for an area, at least 50 percent of the population in a given area must depend on the aquifer for drinking water; a significant public health hazard would result if the aquifer were contaminated, and no reasonable alternative drinking water supplies exist.
1986 AMENDMENTS TO THE SAFE DRINKING WATER ACT.
The 1986 amendments to the SDWA required that the EPA set MCLs for an additional 53 contaminants by June 1989, 25 more by 1991, and 25 every 3 years thereafter. The amendments also required the EPA to issue a maximum contaminant level goal (MCLG) along with each MCL. An MCLG is a health goal equal to the maximum level of a pollutant not expected to cause any health problems over a lifetime of exposure. The EPA is mandated by law to set MCLs as close to MCLGs as technology and economics will permit.
The 1986 amendments banned the use of lead pipe and lead solder in new public drinking water systems and in the repair of existing systems. In addition, the EPA had to specify criteria for filtration of surface water supplies and to set standards for disinfection of all surface and groundwater supplies. The EPA was required to take enforcement action, including filing civil suits against violators of drinking water standards, even in states granted primacy if those states did not adequately enforce regulations. Violators became subject to fines up to $25,000 daily until violations were corrected.
WATER QUALITY CONTROL ACT OF 1987.
Section 304 (1) of the revised Clean Water Act of 1987 (PL 100-4) determines the state of the nation's water quality and reviews the effectiveness of the EPA's regulatory programs designed to protect and improve that water quality. Section 308—known as the Water Quality Control Act—requires that the administrator of the EPA report annually to Congress on the effectiveness of the water quality improvement program.
The main purpose of the Water Quality Control Act is to identify water sources that need to be brought up to minimum standards and to establish more stringent controls where needed. States are now required to develop lists of contaminated waters as well as lists of the sources and amounts of pollutants causing toxic problems. In addition, each state is required to develop "individual control strategies" for dealing with these pollutants.
LEAD CONTAMINATION CONTROL ACT OF 1988.
The Lead Contamination Control Act of 1988 (PL 100-572) strengthened the controls on lead contamination set out in the 1986 amendments to the SDWA. It requires the EPA to provide guidance to states and localities in testing for and remedying lead contamination in drinking water in schools and day care centers. The act also contains requirements for the testing, recall, repair, and/or replacement of water coolers with lead-lined storage tanks or parts containing lead. It attaches civil and criminal penalties to the manufacture and sale of water coolers containing lead.
The ban on lead states that plumbing must be lead-free. In addition, each public water system must identify and notify anyone whose drinking water may be contaminated with lead, and the states must enforce the lead ban through plumbing codes and the public-notice requirement. The federal government gave the EPA the power to enforce the lead ban law by authorizing the agency to withhold up to 5 percent of federal grant funds to any state that does not comply with the new rulings.
REINVENTING DRINKING WATER LAW—1996 AMENDMENTS TO THE SAFE DRINKING WATER ACT.
In 1996 Congress passed a number of significant amendments (PL 104-182) to the SDWA. The law changed the relationship between the federal government and the states in administering drinking water programs, giving states greater flexibility and more responsibility.
The centerpiece of the law is the State Revolving Fund (SRF), a mechanism for providing low-cost financial aid to local water systems to build the treatment plants necessary to meet state and federal drinking water standards. The law also requires states to train and certify operators of drinking water systems. If they do not, states risk losing up to 20 percent of their federal grants. The law requires states to approve the operation of any new water supply system, making sure it complies with the technical, managerial, and financial requirements. The 1996 SDWA gives the EPA discretion in regulating only those contaminants that may be harmful to health, and requires the EPA to select at least five contaminants every five years for consideration for new standards. A further change is that the EPA, when proposing a regulation, now must determine—and publish—whether or not the benefits of a new standard justify the costs.
Furthermore, the law affirms Americans' "right to know" the quality of their drinking water and mandates notification. Water suppliers must promptly (within 24 hours) alert consumers if water becomes contaminated by something that can cause illness and must advise as to what precautions can be taken. In 1998 states began to compile information about individual systems, which the EPA now summarizes in an annual compliance report. As of October 1999 water systems have been required to make that data available to the public. Large suppliers have to mail their annual safety reports to customers, while smaller systems can post the reports in a central location or publish it in a local newspaper. (Information on individual water systems is available on the EPA website at http://www.epa.gov.)
In 1996 Congress directed the EPA to issue a new standard for arsenic in drinking water by January 1, 2001. The existing standard at that time was 50 parts per billion (ppb). The EPA proposed a standard of 5 ppb in June 2000. However, this was too late to resolve scientific and public debate about the new standard in time to meet the January 1 deadline, so Congress extended the deadline. A new standard of 10 ppb became effective in February 2002, but public water systems were given until January 2006 to meet it.
Sources of Drinking Water—Public and Private Supply
According to the EPA there were 161,201 public water supply systems in operation in 2003, serving 302.9 million people. (See Table 6.4.) These included systems that served homes, businesses, schools, hospitals, and recreational parks. About 273.3 million Americans got their water from a community water system. Those who did not get their water from a public system were for the most part in rural areas and got their water from private
TABLE 6.4
Inventory of public water systems, 2003
| Community water systems | |||||
| Ground water | Surface water | Total | |||
| No. of systems | 41,499 | 11,864 | 53,363 | ||
| % of systems | 78% | 22% | |||
| Population served | 86.3 million | 187 million | 273.3 million | ||
| % of population served that depends on each water type | 32% | 68% | |||
| Non-transient non-community water systems | |||||
| Ground water | Surface water | Total | |||
| No. of systems | 18,908 | 778 | 19,686 | ||
| % of systems | 96% | 4% | |||
| Population served | 5.6 million | 730 thousand | 6.3 million | ||
| % of population served that depends on each water type | 88% | 12% | |||
| Transient non-community water systems | |||||
| Ground water | Surface water | Total | |||
| No. of systems | 86,061 | 2,091 | 88,152 | ||
| % of systems | 98% | 2% | |||
| Population served | 10.5 million | 12.8 million | 23.3 million | ||
| % of population served that depends on each water type | 45% | 55% | |||
| SOURCE: Adapted from "Public Water System Inventory Data," in Factoids: Drinking Water and Ground Water Statistics for 2003, U.S. Environmental Protection Agency, Office of Ground Water and Drinking Water, Washington, DC, January 2004 | |||||
wells. Although most systems obtain their water from groundwater, most people receive drinking water from surface water sources. This is because a relatively small number of public systems served large metropolitan areas.
The EPA and state health or environmental departments regulate public water supplies. Public supplies are required to ensure that the water meets certain government-defined health standards. The SDWA governs this regulation. The law mandates that all public suppliers test their water on a regular basis to check for the existence of contaminants and treat their water supplies constantly to take out or reduce certain pollutants to levels that will not harm human health.
Private water supplies, usually wells, are not regulated under the SDWA. System owners are solely responsible for the quality of the water provided from private sources. However, many states have programs designed to help well owners protect their water supplies. Usually, these state-run programs are not regulatory but provide safety information. This type of information is vital because private wells are often shallower than those used by public suppliers. The shallower the well the greater is the potential for contamination.
Chemicals and Contaminants in Drinking Water
All drinking water contains minerals dissolved from the Earth. In small amounts some of these are acceptable because they enhance the quality of the water (for example, by giving it a pleasant taste). A few, such as zinc and selenium, in very small amounts, contribute to good health. Other naturally occurring minerals are not desirable because they may cause a bad taste or odor (as excessive amounts of iron, manganese, or sulfur often do) or because they may be harmful to health.
The health effects from drinking contaminated water can occur either over a short or long period of time, depending on the type of pollutant. Short-term, or acute, reactions are those that occur within a few hours or days after drinking tainted water. Long-term, or chronic, effects occur after water with relatively low doses of a pollutant has been consumed for several years or even over a lifetime. Fortunately, the ability to detect contaminants has improved over the past few decades. Scientists can now identify specific pollutants in terms of 1 part contaminant in 1 billion parts of water. In some cases contaminants can be measured in the trillionths.
Water supplies may contain a wide variety of contaminants that can cause serious health risks. While bacterial infections generally make their presence known quickly by causing illness with fairly obvious symptoms, the effects of noxious chemicals may not be apparent for months, or even years, after exposure. Some pollutants are known carcinogens (cancer-causing agents), while others are suspected of causing birth defects, miscarriages, and heart disease. In many cases the effects occur only after prolonged exposure, but no one can say for sure what is a safe level of exposure.
LEAD.
When water leaves the treatment plant it is relatively free of lead, but it can pick up the metal from lead pipes (and pipes with lead solder) in distribution systems or homes, resulting in tap water containing significant amounts of this highly toxic substance. Unlike many water contaminants, lead has been extensively studied for its prevalence and effects on human health and for ways to eliminate it from the water supply.
Most people understand that drinking water contaminated with lead is very dangerous. Ingested lead causes extremely serious health problems, especially in children, whose developing bodies absorb and retain more lead than adults' bodies do. According to EPA reports, even very low level exposures can result in lowered intelligence, impaired learning and language skills, loss of hearing, reduced attention spans, and poor school performance. High levels damage the brain and the central nervous system, thereby interfering with both learning and physical development. While drinking water is not the only means of lead contamination (lead exists in some paints, soils, and older food containers), the EPA estimates that it accounts for between 10 and 20 percent of total lead poisoning in young children.
Pregnant women are another high-risk group. Lead is believed to cause miscarriages, premature births, and impaired fetal development. It has also been linked to high blood pressure, fatigue, and hearing loss.
Lead is rarely found in either the surface water or groundwater that are the sources of drinking water for most Americans. Lead usually enters the water supply after it leaves the treatment plant. The industries that release the most lead into the environment include lead smelting and refining, copper smelting, steelworks, manufacturers of storage batteries and china plumbing fixtures, iron foundries, and copper mining.
Normally, areas served by lead service lines or residences containing lead interior piping or copper piping with lead solder installed after 1982 are considered high risk. Since 1986 it has been illegal to use lead solder that contains more than 0.2 percent lead. But ripping out and replacing lead piping is extremely expensive. As an alternative some cities are using chemicals to make the water less acidic so that it picks up less lead.
In 1991 the EPA's Lead and Copper Rule set a maximum contaminant level goal for lead at 0 milligrams per liter (mg/L), with water systems required to take action if lead levels reach 0.015 mg/L. The EPA believes this is the lowest level to which water systems can reasonably be required to control the contaminant. If a water supply is found to exceed that amount in more than 10 percent of the homes served, it must be tested twice a year. If levels remain above the standard, the supplier must take steps to reduce those levels. The water supplier must also notify the public about the elevated levels via newspapers, radio, television, and other means and must inform its consumers of additional measures they may take to reduce the levels in their homes.
NITRATES AND NITRITES.
Nitrates and nitrites are nitrogen-oxygen chemicals that combine with organic and inorganic compounds. Once taken into the body, nitrates are converted into nitrites. Nitrates are most frequently used as fertilizer. Primary sources include human sewage and livestock manure, especially from feedlots. Since they are soluble, nitrates can easily migrate into groundwater.
Nitrates in drinking water are an immediate threat to small children. In some babies high levels of nitrates react with red blood cells to cause an anemic condition commonly known as "blue baby." The MCL for nitrates has been set at 10 parts per million (ppm) and for nitrites at 1 ppm. If contaminant levels exceed these standards, a water provider must take steps to reduce the levels—either through ion exchange, reverse osmosis, or electrodialysis—and must notify the public of their presence.
MERCURY.
Mercury is unique among metals in that it can evaporate when released into water or soil. Large amounts of mercury are released naturally from the Earth's crust. Metal smelters, cement manufacture, landfills, sewage, and combustion of fossil fuels are also important sources of mercury release. Mercury is especially dangerous when released into water because it
TABLE 6.5
Waterborne pathogens found in human waste and associated diseases
| Type | Organism | Disease | Effects |
| Bacteria | Escherichia coli (enteropathogenic) | Gastroenteritis | Vomiting, diarrhea, death in susceptible populations |
| Legionella pneumophila | Legionellosis | Acute respiratory illness | |
| Leptospira | Leptospirosis | Jaundice, fever (Well's disease) | |
| Salmonella typhi | Typhoid fever | High fever, diarrhea, ulceration of the small intestine | |
| Salmonell a | Salmonellosis | Diarrhea, dehydration | |
| Shigella | Shigellosis | Bacillary dysentery | |
| Vibrio cholerae | Cholera | Extremely heavy diarrhea, dehydration | |
| Yersinia enterolitica | Yersinosis | Diarrhea | |
| Protozoans | Balantidium coli | Balantidiasis | Diarrhea, dysentery |
| Cryptosporidium | Cryptosporidiosis | Diarrhea | |
| Entamoeba histolytica | Amoebiasis (amoebic dysentery) | Prolonged diarrhea with bleeding, abscesses of the liver and small intestine | |
| Giardia lamblia | Giardiasis | Mild to severe diarrhea, nausea, indigestion | |
| Naegleria fowleri | Amebic | Fatal disease; inflammation of the brain | |
| Meningoencephalitis | |||
| Viruses | Adenovirus | Conjunctivitis | Eye, other infections |
| (31 types) | |||
| Enterovirus (67 types, e.g., polio-, echo-, and Coxsackie viruses) | Gastroenteritis | Heart anomalies, meningitis | |
| Hepatitis A | Infectious hepatitis | Jaundice, fever | |
| Norwalk agent | Gastroenteritis | Vomiting, diarrhea | |
| Reovirus | Gastroenteritis | Vomiting, diarrhea | |
| Rotavirus | Gastroenteritis | Vomiting, diarrhea | |
| SOURCE: "Table 3-20. Waterborne Pathogens Found in Human Waste and Associated Diseases," in Onsite Wastewater Treatment Systems Manual, U.S. Environmental Protection Agency, Office of Research and Development, Office of Water, Washington, DC, February 2002 | |||
tends to accumulate in the tissues of fish. When tainted fish are eaten by humans, mercury poisoning is often the result. The MCL for mercury has been set at 2 ppb.
MICROBIOLOGICAL ORGANISMS.
Many kinds of biological organisms exist in drinking water. These include certain types of bacteria, viruses, or parasites. (See Table 6.5.) These tiny organisms get into the water supplies when the water is contaminated with human or animal wastes. The bacteria, viruses, and parasites that contaminate drinking water can cause flu-like symptoms, including headaches, vomiting, diarrhea, abdominal pain, and dehydration. Although usually not life threatening, they can be debilitating and uncomfortable for their victims.
One type of microscopic parasite that is a common cause of illness is Giardia lamblia. Once thought to be harmless, it is now believed to be the most frequent cause of waterborne epidemics in the United States. Its symptoms include mild-to-severe gastrointestinal pain, vomiting, and diarrhea. Giardia is particularly threatening because it can enter the water supply in any number of ways, including as sewage overflow. It is also easily transmitted from person to person making places with high concentrations of people (for example, day care centers and schools) particularly susceptible to outbreaks.
Cryptosporidium is a one-celled, infectious parasite that frequently contaminates the water supply. Although there are tests for Cryptosporidium, current testing methods cannot determine with certainty whether Cryptosporidium detected in drinking water is alive or whether it can affect humans. In addition, the technology often requires several days to get results, by which time the tested water has already been used by the public and is no longer in the community's water pipes. Consequently, water utilities do not routinely test to detect its presence. (A water utility may voluntarily test for the microorganism, and it is also possible that a state may require water systems to test for it. Otherwise, it is unlikely that a given water system tests for Cryptosporidium.)
Because Cryptosporidium is highly resistant to chlorination, disinfection of water is not a reliable method of preventing exposure to it. The Centers for Disease Control and Prevention (CDC) and the EPA report that the organism can be killed by boiling water for one minute. Outbreaks of Cryptosporidium have generally occurred when turbidity (cloudiness of water due to high particle content) reached 0.9 to 2.0 nephelometric turbidity units.
Coliform bacteria from human or animal wastes can also pose serious health problems. Waterborne diseases such as typhoid, cholera, infectious hepatitis, and dysentery have all been traced to untreated drinking water.
Modern Drinking Water Treatment
The water treatment process begins with choosing the highest quality source available. Raw water must be transported from the source to the treatment plant while groundwater is usually pumped directly into the plant. In many cases the only treatment needed before the water is distributed to consumers is disinfection. Groundwater is naturally filtered as it seeps through layers of rock and soil. However, sometimes it must be treated to remove contaminants that may have percolated down from the surface to the aquifer. In addition, some groundwater must have certain minerals or gases removed to make the water less "hard" (high in natural minerals). Hard water can clog pipes, stain fixtures, and make soap hard to lather.
Surface water is sent to the water treatment plant through aqueducts or pipes. An initial screen at the intake pipe removes large objects. The water is then aerated to eliminate gases and add oxygen. Once the water is inside the plant, chemicals may be added both to clean the water and also to make it more palatable. If the water is hard, lime or soda is added to remove the calcium and magnesium. Chlorine or other such disinfectants may be used as well.
The water is mixed well with the various chemicals, then sent to sedimentation basins where the heavy particles (floc) settle to the bottom and are removed. The water is then sent to filtration beds for polishing—the removal of any remaining small particles and disease-causing protozoa, bacteria, and viruses. (Although filtration removes some viruses, most pass through the filtration process.)
Additional treatment may be required if the raw water contains high levels of toxic chemicals. The pollutants that are the most difficult to detect and remove are often the ones with the greatest potential for severe health effects for large portions of the population.
At various points in the treatment process, the water is monitored by computers and other technological procedures. As the water leaves the treatment plant, chlorine is added as a disinfectant to keep it free of organisms as it travels to customers.
The water then goes to reservoirs where it is stored until needed. These reservoirs may be elevated towers, where gravity brings the water to the consumer without unnecessary energy expense, or ground-level containers that require pumps to move the water. (See Figure 6.16.) The water that flows from the tap should be clear, tasteless, and safe to drink.
Chemicals Deliberately Added to Drinking Water
Water purification facilities deliberately add certain chemicals to drinking water to destroy contaminants that may cause illness and to improve the taste, smell, and look of the water.
CHLORINE.
The most extensively used disinfectant in the United States is chlorine, which is used to kill infectious microorganisms and parasites. Disinfection with chlorine or similar chemicals can prevent outbreaks of salmonellosis, dysentery, and Giardia. Chlorination first began in the early 1900s as an attempt to eliminate cholera and typhoid.
Chlorination is not risk free, however. Chlorine reacts with organic chemicals to form trihalomethanes (THMs) that have been shown to cause cancer in laboratory animals. In 1979 the EPA established regulations limiting the amount of THMs to 0.1 mg/L for water supplies serving 10,000 people or more. The EPA and the medical community continue to study the effects of chlorine. Most concerns about chlorine involve possible damage to the Earth's ozone layer. Some water systems now use ozone gas instead of chlorine. Ozone, bubbled through water, can kill more microorganisms than chlorine and may present less risk.
FLUORIDE.
Fluoride was first added to drinking water in 1945 to prevent tooth decay. Since that time most community water systems in the United States have introduced water fluoridation. Because the fluoridation of drinking water proved effective in reducing dental cavities, researchers also developed other methods to deliver fluoride to the public (toothpastes, rinses, and dietary supplements). The widespread use of these products has assured that virtually all Americans have been exposed to fluoride. The American Dental Association estimated in 1992 that each $1 expenditure for water fluoridation results in a savings of approximately $80 in dental treatment costs.
There have been concerns about the effects of fluoridation since it was first introduced. The Public Health Service has recommended further assessment of potential problems, although it notes that fluoridation is believed to be greatly beneficial for a number of bone-related conditions.
How Clean Is Our Drinking Water?
Safe drinking water is a cornerstone of public health. Fortunately, the nation's drinking water is generally safe. The vast majority of U.S. residents receive water from systems that have no reported violations of MCLs and no flaws in treatment techniques, monitoring, or reporting. Nevertheless, numerous studies have found some deficiencies in those systems, and recent measurements suggest areas of potential danger.
In accordance with the 1996 SDWA amendments, public water systems are mandated to submit compliance reports on the quality of their drinking water. Figure 6.17 shows the states with systems that violated water quality levels or treatment standards in fiscal year 2002.
Incidence of Disease Caused by Tainted Water—CDC Surveillance Report
It is difficult to know how many illnesses are caused by contaminated water. People may not know the source of many illnesses and may attribute them to food (which may also have been in contact with polluted water), chronic illness, or other infectious agents. The EPA notes that some researchers think that the actual number of drinking water–related diseases may be 25 times the reported number. They believe most are not reported
FIGURE 6.16
Water treatment process
because victims believe them to be "stomach upsets" and simply treat themselves.
Since 1971 the CDC and the EPA have collected and reported data that relate to waterborne-disease outbreaks.
The latest report available from the CDC, Surveillance for Waterborne-Disease Outbreaks—United States, 1999–2000 (November 2002), includes data about outbreaks associated with drinking water, recreational water, and occupational exposure. The CDC defines an outbreak as
FIGURE 6.17
Percentage of community water systems in each state with water quality violations, fiscal year 2002
an incident in which at least two people develop a similar illness that evidence indicates was probably caused by ingestion of drinking water or exposure to water in recreational or occupational settings.
According to the CDC, from January 1999 through December 2000 there were 39 outbreaks that sickened 2,068 people and caused two deaths associated with drinking water reported in 25 states. The specific microbe or chemical cause of the outbreaks was identified in 22 of the cases. Pathogens were blamed in 20 of the cases, while chemicals were blamed in the other two cases. Infectious organisms were suspected of being the cause in the remaining 17 cases. Most (72 percent) of the 39 outbreaks were linked to ingestion of groundwater, primarily from private wells not regulated by the EPA.
The CDC report notes that the proportion of drinking water outbreaks associated with surface water increased from 12 percent during 1997–1998 to 18 percent during 1999–2000. The proportion linked with groundwater sources increased by 87 percent from the previous reporting period.
The CDC found evidence that during 1999–2000 recreational water exposure in 23 states caused 59 outbreaks that sickened 2,093 people and caused four deaths. The illnesses involved included gastroenteritis, dermatitis, primary amebic meningoencephalitis, leptospirosis, Pontiac fever, and chemical keratitis. Most of the victims were exposed at swimming pools, interactive fountains, or hot tubs. Two outbreaks associated with occupational exposure caused leptospirosis and Pontiac fever.
Milwaukee—"The Nation's Worst Drinking Water Disaster"
In April 1993, 403,000 residents of Milwaukee became victims of what is considered the worst drinking water disaster the nation has experienced. Cryptosporidium flourished in the city water supply, which had been turbid for several days. For a week more than 800,000 residents were without potable (drinkable) tap water. By the end of the disaster more than 40 people lost their lives because of the outbreak. In addition to the human suffering, the disease cost an estimated $37 million in lost wages and productivity.
Among the possible causes for the outbreak were the advanced age and flawed design of the Milwaukee water plant, which returned dirty water back to the reservoir. Other explanations included failure of plant personnel to react quickly when turbidity levels rose; critical monitoring equipment that was broken at the time turbidity levels peaked; a water intake point that was vulnerable to contamination; and a slaughterhouse, feedlot, and sewage treatment plant that were located upriver from the plant. Water treatment experts blamed the complacency of officials and false assumptions based on a history of quality water dispersal.
As a result of the disaster, Milwaukee launched one of the most aggressive drinking water programs in the country. Each week the city monitors for Cryptosporidium and has set a zero standard for the parasite. It has also adopted a turbidity standard five times tougher than federal regulations. Turbidity, although harmless in itself, is often a precursor to the presence of organisms such as Cryptosporidium.
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