A two year profile of drinking water quality in the US
Just Add Water: Just Add Water
During 1994-1995, 18,542 of the nation's drinking water systems, serving a population of over 45 million people, reported violations of health standards for chemical, radiological or microbial contaminants, or filtration and disinfection and water treatment requirements. These 18,542 water utilities represent more than 10% of the nation's 173,000 public drinking water supplies.
These figures derived from EWG analysis of more than 16 million computer records submitted by state agencies significantly underestimate the scope of the problem because many states either fail to report violations, or do not report these violations on time (quarterly, as required by EPA). All violations of SDWA standards for the year 1995 should have been reported to the EPA by March 31, 1996.
Late reporting and entry into the EPA Safe Drinking Water Information System (SDWIS) apparently has been exacerbated this year by several federal government shutdowns. As a result, it is impossible at this time to determine whether the affected population has increased as compared to estimates of the number of people affected by health violations in the previous two year period. A full accounting of all violations for 1995 will not be possible for several months to a year.
Even so, this partial record of health violations indicates that basic bacterial contamination problems - represented by violations of the fecal and chronic coliform standards, and violations for inadequate filtration or failure to filter - increased in 1994-1995 compared to the 1993-1994 reporting period. Total violations for chemical contaminant health standards (excluding lead and radiation) decreased slightly during 1994-1995, while the number of systems reporting chemical contaminant violations increased substantially.
Compared with violations calculated one year ago, the population served water that violated the chronic coliform standard, increased by 700,000, from 22. 7 million people in 1993-1994 to 23.4 million people in 1994-1995. The population served water that was inadequately filtered or disinfected rose by almost 4 million, from 16.4 million people in 1993-1994, to 20.3 million in 1994-1995. Comparable fecal coliform violations remained the same at 11.6 million people served, while the number of communities reporting violations increased by ten percent.
In 1994-1995, 325 drinking water systems reported health standard violations for forty different chemical contaminants. The number of people served water that violated the federal health standard for cancer causing by-products of chlorination (total trihalomethanes or TTHMS) remained that same at about 640,000 people. The number of people served water that violated chemical contaminant standards (excluding nitrate and TTHMs), decreased from 1 million to about 890,000, but the number of systems reporting chemical contaminant standard violations increased by 50 percent from 122 systems in 1993-1994, to 197 systems in 1994-1995.
The EPA testing requirements for lead complicate comparisons between 1994-1995, and 1993-1994. Monitoring requirements for radiation went into effect in 1992 and 1993. During these two years, thousands of water systems serving millions of people identified unsafe levels of lead in their water systems that had previously gone undetected. Once these problems were identified, many water utilities have started to fix them, and thus are no longer reported in violation of the EPA lead action level and related requirements - even though it will take years to be certain that lead and radiation problems have been fully fixed.
In general, this process represents a success for the Safe Drinking Water Act and shows why the law must be must strengthened, not weakened. After all, it was only through a strong drinking water law that water suppliers found and fixed these lead and radioactivity problems in the first place. Yet just as the Safe Drinking Water Act appears to be working, efforts are afoot to weaken the Act's health protections. In the case of lead, a roll back of monitoring and health standards under federal law could mean that millions of people would still be drinking unsafe levels of these contaminants in their tap water.
All violations discussed in this report are violations of health or water treatment standards, meaning that any system that was reported served water that had unsafe levels of hazardous microorganisms, or chemicals that cause acute or chronic health effects that include cancer, birth defects, and disruption of the hormone (endocrine) systems.
Basic bacterial contamination of tap water was the most common problem. In 1994-1995, 11,915,000 individuals were served by 2,726 water systems with contamination by potentially disease-causing fecal matter (Table 1). An even larger population, 24,719,000, were served by 12,246 water systems with chronic coliform bacterial contamination. And many water systems fail to adequately treat their water to remove these hazardous microbes. In the two year period, over 20 million Americans were served water from 1,478 water systems that failed to filter or adequately disinfect their tap water.
Chemical contamination also poses serious risks in tap water. In 1994-1995, more than five million American's drank tap water from 3,641 water suppliers that exceeded EPA's Lead Action Level or otherwise violated EPA's Lead and Copper Rule. And 2.3 million people received tap water from over 1,000 water suppliers that violated an EPA standard for toxic chemicals or pesticides. This includes 471,000 people served water that violated the EPA nitrate standard (nitrate causes an acute illness known as blue baby syndrome in infants), 632,000 people served water that violated EPA standards for cancer-causing byproducts of chlorination known as trihalomethanes, and 279,000 people served water contaminated with unsafe levels of radiation.
Delaware was the state with the highest percentage of systems with violations of health standards in this two year period, followed by South Dakota, Arizona, and Idaho (Table 2).
While some of these violations have been remedied, this does not mean that the remedies are permanent. Analyses of EPA data indicate that in any given year, thousands of new violations of standards will plague water suppliers throughout the country (NRDC 1994, NRDC 1995, EWG 1995). EPA's SDWIS database provides a two year snapshot of drinking water contamination at unsafe levels with numerous chemicals and biological hazards. Thus, while many of these problems have been fixed, many new ones will undoubtedly occur. This is why all Americans rely on the federal Safe Drinking Water Act to identify problems in their water system, and to protect them from new and emerging problems such as Cryptosporidium. Weakening the Safe Drinking Water Act will not make these problems go away. It will, however, make it difficult, if not impossible, for many communities to identify and solve new or persistent tap water contamination problems.
Schools, Hospital, and Daycare Centers With Drinking Water Violations
Thousand of schools, day care centers and hospitals across the country maintain their own water supplies. Nationwide, 1,583 schools, hospitals and daycare centers, providing tap water to over 700,000 schoolchildren or hospitalized individuals, violated EPA health standards in 1994-1995. These non-community systems represent only a small part of the vulnerable population at risk - thousands more schools or hospitals receive their tap water from municipal water suppliers that also suffered from SDWA violations in 1994-1995. These small, generally privately owned water systems are a particular concern because draft legislation from Representative Thomas Bliley would explicitly roll back standards for small water systems, allowing them to serve water that contains more toxic chemicals and hazardous microorganisms than is allowed in large water systems.
These health standard violations represent serious risks. The most common problem among schools, hospitals, and daycare centers was exceeding EPA's Lead Action Level (Table 3). Over 850 of these systems, serving water to 317,000 schoolchildren or hospitalized individuals, had excess amounts of lead in the water - a contaminant that is notorious for retarding children's mental development. Many of these water systems also reported violations of bacterial contaminant standards that can cause acute illness and gastrointestinal distress. More than one hundred and sixty schools, hospitals and daycare centers, serving water to 63,000 individuals violated the EPA standard for fecal matter in tap water. Another 678 of these systems, serving tap water to 339,000 people, violated EPA's standard for chronic coliform bacteria.
Ohio, with 140, had the most schools, hospitals and daycare centers reported to EPA for violating a health standard, followed by North Carolina (132), Virginia (107), Florida (96), New Jersey (91) and Maryland (86) (Table 2).
The Nature of the Violations
Fecal Matter. Fecal coliform bacteria (E. Coli) indicate that the water has been contaminated by sewage or animal waste that contains other disease causing microorganisms. These bacteria in drinking water present an immediate acute human health risk. Each violation of this standard represents a period of from a few days up to a month or longer where finished tap water provided to the public contained illegal and acutely unsafe levels of fecal bacteria.
During 1994 and 1995, 11.9 million people served by 2,726 water systems, drank water contaminated with fecal coliform at levels above federal health standards at least once.
New York City was the largest water system to find unsafe levels of fecal coliform in drinking water. This violation, however, occurred in 1994, and since that time the water utility has undertaken a substantial program to fix the problem. The next largest systems with a violation were Louisville, Kentucky; Washington, DC; Tulsa, Oklahoma; Jersey City, New Jersey, and Arlington, Virginia, which collectively account for approximately 15 percent of the population exposed to fecal coliform in violation of federal standards (Table 4). In Louisville the utility claims that fecal coliform violations in 1994 and 1995 were both caused by improper disposal of cleaning wastes in public restrooms.
Most of these large communities with problems reported a single fecal bacteria violation. Only eight water systems (Table 5) reported multiple violations of fecal coliform standards. Kearney, Nebraska, with three violations, had the most violations of fecal standards among large communities.
Chronic Coliform Bacteria. Violation of the chronic (monthly) coliform bacteria standard indicates pervasive contamination of drinking water with potentially disease causing microorganisms (although the detected coliform are not toxic themselves, they do indicate likely contamination by hazardous microbes). A chronic coliform standard is exceeded only when more than five percent of all samples collected during a month contain coliform bacteria.
A total of 12,246 water systems serving 24.7 million people, violated the monthly coliform standard at least once during the two year period. New York City and Washington, DC were the two largest cities with at least one violation in the two year period, followed by water utilities in Greenville, South Carolina, Jersey City, New Jersey, and Bakersfield and Modesto, California (Table 6).
Twenty water systems serving 10,000 or more people suffered from four or more violations of the chronic coliform standard in 1994-1995 (Table 7). Among these large systems, the Firgrove Mutual system in Washington had the most monthly coliform violations in the 24 month period, with nine. Moore, Oklahoma and the East Wenatchee Water District in Washington were next with 8 violations in the two year period, followed by the Tangipahoa Waterworks in Louisiana with seven.
Inadequate disinfection/Failure to filter. Violations for inadequate disinfection or outright failure to filter drinking water affected over 20 million individuals served by 1,478 water systems. These water systems all violated EPA's Surface Water Treatment rule (SWTR), which requires that water suppliers that use rivers or reservoirs that are prone to bacterial or parasitic contamination adequately filter their water. SWTR violations represent serious health risks. For example, violations for high turbidity levels (one of the criteria for meeting the SWTR) are a proxy indicator for microbial contamination. The only indication of a problem during the Milwaukee Cryptosporidium outbreak that made 400,000 people sick was an increase in turbidity of the water. Other violations of the SWTR include such problems as inadequate contact time of disinfection material with the water. These violations, which indicate that water treatment is not adequate to disinfect water, can increase risks of illness and disease.
Because most large cities rely on rivers and reservoirs for their tap water, the water suppliers that violated the filtration and disinfection requirement in 1994-1995 were among the largest in the country. The largest communities to suffer from violations of this requirement were New York, San Francisco, Pittsburgh, Tucson, and Fort Worth (Table 8). Persistent violations can indicate more serious health risks. At least 9 communities violated the standard for 12 or more months during the 2 year period (Table 9). Because of Safe Drinking Water Act requirements many of these communities, including Ann Arbor, Michigan have identified problems, and are making necessary improvements to treatment plants.
Lead. Lead is one of the most pervasive contaminants in U.S. drinking water. It is primarily a problem associated with lead pipes and solder used in older water delivery systems. Lead presents serious health risks to infants and children and can cause permanent loss of mental capacity at very low levels of contamination. In fact, no level of lead exposure has been identified that does not cause some measurable decrease in mental acuity in large populations if exposure occurs in childhood. For enforcement purposes, there is no Maximum Contaminant Level for lead. When the lead action level is exceeded, therefore, it is not technically considered a violation of the law. Like an MCL, however, when the lead action level is exceeded it represents a serious human health threat, and utilities are required to remediate the problem.
In 1994-1995, 3,062,000 million people in 2,634 communities drank water from systems that exceeded an EPA lead action level. This translates into hundreds of thousands people drinking water contaminated with lead at levels that can cause permanent loss of mental capacity in exposed children. Another 1,977,000 people in 1,007 communities drank from systems that violated EPA's Lead Rule because they did not take the necessary steps to solve previously identified lead problems, or to notify the public of their existence.
Under the Safe Drinking Water Act, thousands of water systems began testing for lead in 1992 and 1993 and many exceeded lead action levels. Most of these water systems have notified the public of problems, and have taken steps to begin treat the water to reduce lead contamination. These steps include treating the water to make it less corrosive, so it will leach less lead into drinking water. Although it will take years for these water suppliers to solve problems, most of these water suppliers are no longer listed as exceeding lead standards.
Based on reported data, Charleston, South Carolina was the largest city exceeding the EPA lead action level in 1994-1995 (Table 10). New Bedford and Brockton, MA; Anniston, Alabama, and Camden, New Jersey round out the five largest water systems that have exceeded the lead action level.
Chemical Contaminants In addition to lead, Safe Drinking Water Act regulations govern four main types of chemical contaminants: pesticides and industrial chemicals, nitrate, radioactive contaminants, and trihalomethanes (cancer-causing byproducts of chlorination of drinking water). Violations of these standards indicate that customers were exposed to illegal levels of toxic contaminants that pose acute or chronic risks. Chemicals such as nitrate, which causes potentially fatal blue baby syndrome, pose acute risks, while pesticides or industrial chemicals cause long term effects that include birth cancer, birth defects, and disruption of the endocrine system. In 1994-1995, 2.3 million people were served by 1,050 water systems that reported violating an EPA standard for radiation, nitrate, pesticides, industrial contaminants, or trihalomethanes.
The reported violations also significantly underestimate the true extent of chemical contamination problems. Many toxic chemicals commonly found in drinking water are not even regulated. Cyanazine and acetochlor, two unregulated pesticides, are found in the tap water of more than 10 million people; radon is found in the tap water of more than eighty million people, yet there is no standard. Other standards are weak and out of date. The standard for arsenic, found in the tap water of more than fifty million people, dates from World War II, before arsenic was even known to be a carcinogen.
Nitrate. Exposure to nitrate in drinking water above the current EPA standard of 10 ppm poses an immediate risk to infants of contracting blue baby syndrome (or methemoglobinemia), a potentially deadly condition caused by lack of oxygen in the blood (NRC 1995). Because the current EPA standard contains no safety factor to protect infants from acute illness, violations of this standard are of immediate concern.
In 1994-1995, 471,700 people drank water from 588 water suppliers that violated the EPA nitrate standard. The largest water suppliers to violate a nitrate standard were Modesto and Norco, California, and Dodge City, Kansas (Table 11). The principal cause of nitrate contamination of water supplies is overuse of nitrogen fertilizer, which accounts for approximately 80 percent of the nitrogen added to the environment each year (EWG 1996).
These reported nitrate violations significantly underestimate the problem because they do not include hundreds of thousands of water drinkers who are supplied from systems that violate the standard, but receive special waivers from their state contingent upon adequately notifying the public of problems, or the hundreds of water suppliers that have been forced to close wells because of nitrate contamination (EWG 1996).
For example, for several weeks to one month each year, the city of Columbus, Ohio serves water contaminated with nitrate above the EPA's health standard of 10 ppm. This is not considered a violation of the standard because the city notifies the public of the problem.
Radiation. Radiation causes cancer in humans. Because most water exceeding radiation standards is groundwater, violations typically represent permanent, but naturally occurring contamination of groundwater with radioactive elements. Exposure to radioactive drinking water is particularly risky because it translates into daily exposure to a known cancer causing agent at levels deemed unsafe by federal health authorities.
At least 279,500 people were served by 88 water systems with radiation levels that exceed federal standards. The five largest communities affected by violations of standards for radioactive drinking water in 1994-1995 are Joliet, DeKalb, Bellwood, Lake Zurich, and West Chicago, all in Illinois (Table 11).
Chemicals and Pesticides. The nation's drinking water is contaminated with hundreds of industrial chemical pollutants and pesticides. Since 1987, 67 pesticides and pesticide metabolites were found in the surface waters that supply drinking water in the Midwest alone (EWG 1994). Several hundred chemical contaminants have been detected in surface waters that provide drinking water for millions of people.
Forty different pesticides or industrial chemicals were found in 325 water systems at levels exceeding federal health limits over the two year period 1994-1995 (Table 12). These systems serve 935,000 people. For the second consecutive year, atrazine was the pesticide found most frequently above EPA standards, with 58 systems serving 114,500 people reporting violations in 1994-1995. Tetrachloroethylene violated health standards next most often, in 44 systems serving 411,800 people, followed by trichloroethylene at unsafe levels in 30 systems serving 278,100 people.
The North Pennsylvania Water Authority, with tetrachloroethylene problems, was the largest water system to report a chemical violation, followed by water suppliers in Ridgewood, Camden City and Parsippany-Troy Hills New Jersey (Table 11).
The majority of chemical and pesticide contamination, however, does not exceed federal health standards, and is not reported to the EPA. This is in large part because chemical and pesticide contaminant standards are weak. Special risks faced by infants, children or sensitive subpopulations are ignored. In general, and within broad public health guideposts, the harder it is to remove a chemical contaminant, the more of it people are allowed to drink. Because the standards are so weak, violations typically indicate major problems.
Conversely, contamination at levels below federal health standards does not mean that exposure is safe, or that people will not suffer illness or adverse health affects after long term exposure. Moreover, chemicals and pesticides are set for single contaminants, and do not account for multiple contaminants interacting in the water and the human body. And again, for many commonly occurring chemicals such as cyanazine or radon, there are no enforceable standards.
Trihalomethanes. Chlorination of drinking water provides fundamental health protections for hundreds of millions of people by killing microorganisms present in water that would otherwise cause widespread human disease. Chlorination of water that is high in organic material (animal waste, treated sewage outflow, degraded leaves and soil, etc.), however, can produce toxic cancer causing by-products known as trihalomethanes (THMs).
Over 630,000 people served by 42 systems drank water that exceeded federal health standards for trihalomethanes during 1994-1995. The largest trihalomethane violator was Fort Bragg, North Carolina followed by Anderson, Indiana and Mansfield, Ohio (Table 11). The systems with the most violations were Lancaster County, South Carolina and New Shoreham, Rhode Island, each with four violations of the trihalomethane health standard during the two year period examined here (Table 11).
The solution to this problem is to keep drinking water source water as clean as possible, and to disinfect more carefully so as not to overproduce hazardous by-products. More than ten studies show that THMs cause rectal and bladder cancer in humans, and a recent review of these studies published in the American Journal of Public Health estimated that 10,000 people get cancer each year associated with trihalomethanes (Morris et.al. 1992). Additional studies show that THMs can cause birth defects at levels below the federal standard. EPA is currently facing a negotiated regulatory deadline to tighten these standards. The chlorine industry has aggressively lobbied to weaken these provisions, and draft legislation written by Representative Thomas Bliley of Virginia would delay or weaken the regulations to control these cancer causing byproducts.