Drinking Water Standards
Priority Rulemakings
The Safe Drinking Water Act requires EPA to revise the existing 50 parts per billion (ppb) standard for arsenic in drinking water. EPA is implementing a 10 ppb standard for arsenic. Arsenic is a semi-metal element in the periodic table. It is odorless and tasteless. It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices.
Non-cancer effects can include thickening and discoloration of the skin, stomach pain, nausea, vomiting; diarrhea; numbness in hands and feet; partial paralysis; and blindness. Arsenic has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate.
EPA has set the arsenic standard for drinking water at .010 parts per million (10 parts per billion) to protect consumers served by public water systems from the effects of long-term, chronic exposure to arsenic. Water systems must comply with this standard by January 23, 2006, providing additional protection to an estimated 13 million Americans.
EPA proposed a rule which specified the appropriate use of disinfection in ground water and addressed other components of ground water systems to assure public health protection.
.EPA proposed the Ground Water Rule on May 10, 2000. The purpose of the rule is to provide for increased protection against microbial pathogens in public water systems that use ground water sources. EPA is particularly concerned about ground water systems that are susceptible to fecal contamination since disease-causing pathogens may be found in fecal contamination.
The GWR will apply to public water systems that serve ground water. The rule also applies to any system that mixes surface and ground water if the ground water is added directly to the distribution system and provided to consumers without treatment.
EPA estimates that approximately 20 percent of human exposure to lead is attributable to lead in drinking water.
On June 7, 1991, EPA published a regulation to control lead and copper in drinking water. This regulation is known as the Lead and Copper Rule (also referred to as the LCR or 1991 Rule). Lead and copper enter drinking water primarily through plumbing materials. Exposure to lead and copper may cause health problems ranging from stomach distress to brain damage.
The treatment technique for the rule requires systems to monitor drinking water at customer taps.If lead concentrations exceed an action level of 15 ppb or copper concentrations exceed an action level of 1.3 ppm in more than 10% of customer taps sampled, the system must undertake a number of additional actions to control corrosion. If the action level for lead is exceeded, the system must also inform the public about steps they should take to protect their health and may have to replace lead service lines under their control.
A major challenge for water suppliers is how to balance the risks from microbial pathogens and disinfection byproducts. This web site includes development of the Ground Water Rule, as well as the two new final rules: Long Term 2 Enhanced Surface Water Treatment Rule and Stage 2 Disinfectants and Disinfection Byproducts Rule.
This site provides information about microbial pathogens and disinfection byproducts as related to drinking water.
In many cases, source water from a lake, river, reservoir or ground water aquifer needs to be disinfected to inactivate (or kill) microbial pathogens. Microbial pathogens include a few types of bacteria, viruses, protozoa, and other organisms. Some pathogens are often found in water, frequently as a result of:
- Fecal matter from sewage discharges
- Leaking septic tanks
- Runoff from animal feedlots into bodies of water
To protect drinking water from these pathogens, water suppliers often add a disinfectant to drinking water such as chlorine. However, disinfectant practices can be problematic because:
- Certain microbial pathogens, such as Cryptosporidium, are highly resistant to traditional disinfection practices.
- Disinfectants themselves can react with naturally-occurring materials in the water to form byproducts, such as trihalomethanes and haloacetic acids, which may pose health risks.
A major challenge for water suppliers is how to balance the risks from microbial pathogens and disinfection byproducts. It is important to provide protection from microbial pathogens while simultaneously minimizing health risks to the population from disinfection byproducts. There are several existing and future rules that are designed to achieve these goals.
This web site is designed to provide you with information about microbial pathogens, disinfection byproducts, existing and future rules, as well as guidance materials and background information.
Training
This site provides information about past and upcoming training for the implementation of the Stage 2 and LT2 rules. On this site you will find information about webcasts, train the trainer sessions, and other training opportunities designed to help you with the implementation of the Stage 2 and LT2 rules.
- Long Term 2 Enhanced Surface Water Treatment Rule (LT2 rule)
LT2 rule is to reduce illness linked with the contaminant Cryptosporidium and other disease-causing microorganisms in drinking water.
- Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBP)
Stage 2 DBP rule builds upon earlier rules that addressed disinfection byproducts to improve your drinking water quality and provide additional public health protection from disinfection byproducts. Future Rules
EPA has proposed a Ground Water Rule that specifies the appropriate use of disinfection while addressing other components of ground water systems to ensure public health protection.
Existing Rules:Long Term 1 Enhanced Surface Water Treatment Rule (LT1) (January 14, 2002)
The Long Term 1 Enhanced Surface Water Treatment Rule strengthens control of microbial contaminants, particularly Cryptosporidium, for small systems—those systems serving fewer than 10,000 people. It is the smaller system counterpart of the Interim Enhanced Surface Water Treatment Rule.
Filter Backwash Recycling Rule (FBR) (June 8, 2001)
The Filter Backwash Recycling Rule requires public water systems (PWSs) to review their backwash water recycling practices to ensure that they do not compromise microbial control.
Stage 1 Disinfectants and Disinfection Byproducts Rule (Stage 1 DBP) (December 16, 1998)
The Stage 1 Disinfectants and Disinfection Byproducts Rule reduces exposure to disinfection byproducts for customers of community water systems and non-transient non-community systems, including those serving fewer than 10,000 people, that add a disinfectant to the drinking water during any part of the treatment process.
Interim Enhanced Surface Water Treatment Rule (IESWT) (December 16, 1998)
The Interim Enhanced Surface Water Treatment Rule improves control of microbial contaminants, particularly Cryptosporidium, in systems using surface water, or ground water under the direct influence of surface water, that serve 10,000 or more persons. The rule builds upon the treatment technique requirements of the Surface Water Treatment Rule.
Surface Water Treatment Rule (SWT) (June 28, 1989)
The Surface Water Treatment Rule seeks to prevent waterborne diseases caused by viruses, Legionella, and Giardia lamblia. These disease-causing microbes are present at varying concentrations in most surface waters. The rule requires that water systems filter and disinfect water from surface water sources to reduce the occurrence of unsafe levels of these microbes.
Total Coliform Rule (June 29, 1989)
The Total Coliform Rule set both health goals and legal limits for total coliform levels in drinking water. The rule also details the type and frequency of testing that water systems must do.
MTBE (methyl-t-butyl ether) is a member of a group of chemicals commonly known as fuel oxygenates. MTBE replaces the use of lead as an octane enhancer since 1979.
What is MTBE?
MTBE (methyl-t-butyl ether) is a member of a group of chemicals commonly known as fuel oxygenates. Oxygenates are added to fuel to increase its oxygen content. MTBE is used in gasoline throughout the United States to reduce carbon monoxide and ozone levels caused by auto emissions. MTBE replaces the use of lead as an octane enhancer since 1979. For additional information, please go to EPA's general MTBE site.
How does MTBE contaminate water supplies?
Releases of MTBE to ground and surface water can occur through leaking underground storage tanks and pipelines, spills, emissions from marine engines into lakes and reservoirs, and to some extent from air deposition.
How do I know if I have MTBE in my water?
You can determine if your water contains MTBE the following ways. If your drinking water is supplied by a public water system, you can contact the system directly and ask whether they monitor for MTBE and what levels, if any, have been detected. In 2001, public water systems serving most of the population will be required to monitor for MTBE. If you have a private well, your local health department may be able to tell you if MTBE has been found in water in your area. If you want to get your water tested, call the Safe Drinking Water Hotline (800-426-4791) to get the phone number for the office in your state that certifies drinking water laboratories.
How can I remove MTBE from my water?
Public water systems can use existing technologies such as air stripping, granular activated carbon (GAC), and advanced oxidation to remove MTBE contamination. Some home treatment units can also remove MTBE in tap water. The EPA does not certify the effectiveness of home treatment units since it only regulates public water supplies. NSF International has a respected certification program for home treatment systems. They do certify home treatment systems for MTBE and other regulated contaminants. Another source of information on home treatment devices is the Water Quality Association . The Underwriters Laboratories, Inc. website also provides further insight into home treatment devices.
What is the Office of Water doing to address MTBE concerns?
Due to its widespread use, reports of MTBE detections in the nation's ground and surface water supplies are increasing. The Office of Water is actively involved in identifying the issues and addressing the concerns over the potential presence of MTBE in our water supplies. The Office of Water is participating in MTBE projects in the following areas:
Blue Ribbon Panel
EPA has established a panel of leading experts in the fields of public health, the scientific community, automotive fuels, water utilities, and local and State environmental officials to focus on the issues posed by the continued use of MTBE and other oxygenates in gasoline. The panel will look at the role of oxygenates in meeting clean air standards; evaluate its efficiency and other alternatives; assess the behavior of oxygenates in the environment; review known health effects; look at the cost of production and use and the product's availability; study causes of ground and drinking water contamination from motor vehicle fuels; and examine cleanup technologies for water and soil. In September 1999, the panel released its final report on the findings and recommendations on how best to ensure public health and environmental protection while maintaining clean air and water benefits.
In response to the recommendations of the Blue Ribbon Panel, the Office of Water issued a memo to the States regarding concerns about MTBE and how to protect sources of drinking water. The memo encourages early MTBE monitoring under the Unregulated Contaminant Monitoring Rule and assessing the impact of MTBE sources into source water assessments, and highlights the development of a secondary drinking water standard.
MTBE and the Safe Drinking Water Act
As part of implementing the Safe Drinking Water Act Amendments of 1996, the Office of Water has placed MTBE on the drinking water Contaminant Candidate List (CCL) for further evaluation to determine whether or not regulation with a National Primary Drinking Water Regulation (NPDWR) is necessary. The CCL divided the contaminants among those which are priorities for additional research, those which need additional occurrence data, and those which are priorities for consideration for rulemaking. The Agency determined that MTBE needs more health effects research and occurrence data before a regulatory determination can be made. Information gathered from the Agency's research and data collection efforts will assist our regulatory determination.
- In addition, MTBE has been included in the final Unregulated Contaminant Monitoring Regulation that will require all large public water systems and a statistical sampling of small and medium public water systems to monitor and report the presence of MTBE in their water supplies.
- As an additional interim measure, EPA responded to requests for guidance by reviewing and updating an advisory for MTBE in December 1997. This Drinking Water Advisory: Consumer Acceptability and Health Effects Analysis provides guidance to communities that may become exposed to drinking water contaminated with MTBE. The advisory recommends control levels that prevent adverse taste and odor (i.e. 20 to 40 parts per billion). Managing water supplies to avoid the unpleasant taste and odor effects at levels in this range also provides protection against any potential adverse health effects with a very large margin of safety.
Research
To facilitate the advancement of crucial scientific knowledge needed for MTBE and other fuel oxygenates in the environment, the Office of Water has participated in an agency-wide task force on an "Oxygenates in Water: Critical Information and Research Needs" (Needs) document. The Needs document identifies key issues and information needed to support risk assessment and risk management of MTBE and other oxygenates in water, and lists more than 40 projects that are currently underway or anticipated. EPA is conducting a key pharmacokinetic study that will help clarify the potential health risks from MTBE in drinking water more quickly than the amount of time (likely more than four years) it would require to conduct and analyze a two-year drinking water study in rodents.
Occurrence
The Agency is very concerned and has been closely following the increasing detections of MTBE in the ground and surface water supplies throughout the nation. While most MTBE detections typically occur at levels below those recommended in EPA's Drinking Water Advisory, there have been instances of contamination at much higher levels of potential health concern. We are working together with the U.S. Geological Survey to assess the frequency and levels of MTBE occurrence in geographic regions using MTBE as part of the Reformulated Gasoline (RFG) program. This study, as well as an upcoming national occurrence survey sponsored by American Water Works Association Research Foundation and increased monitoring studies by many states, will help clarify the extent to which MTBE may threaten the nation's water supplies.
For printed copies of EPA Office of Water documents please contact either the Safe Drinking Water Hotline (1-800-426-4791), Monday through Friday from 9:00 a.m. to 5:30 p.m. Eastern time.
EPA has updated its standards for radionuclides in drinking water.
EPA has revised the current radionuclides regulation, which has been in effect since 1977, by requiring new monitoring provisions that will ensure that all customers of community water systems will receive water that meets the Maximum Contaminant Levels for radionuclides in drinking water. EPA also has promulgated a standard for uranium as required by the 1986 amendments to the Safe Drinking Water Act. The current standards are: combined radium 226/228 of 5 pCi/L; a gross alpha standard for all alphas of 15 pCi/L, not including radon and uranium; a combined standard of 4 mrem/year for beta emitters. The new MCL for uranium is 30 µg/L. This final rule will provide improved health protection for 420,000 persons through monitoring improvements for the combined radium-226/-228 standard (a carcinogen) and for an additional 620,000 persons through a new standard for uranium (a kidney toxin and carcinogen) in drinking water.
Radon is a naturally-occurring radioactive gas that may cause cancer, and may be found in drinking water and indoor air.
Radon is a naturally-occurring radioactive gas that may cause cancer, and may be found in drinking water and indoor air. Some people who are exposed to radon in drinking water may have increased risk of getting cancer over the course of their lifetime, especially lung cancer. Radon in soil under homes is the biggest source of radon in indoor air, and presents a greater risk of lung cancer than radon in drinking water. As required by the Safe Drinking Water Act, EPA has developed a proposed regulation to reduce radon in drinking water that has a multimedia mitigation option to reduce radon in indoor Back
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