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Frequently Asked Questions

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Find an answer or ask a question about drinking water and ground water programs authorized under the Safe Drinking Water Act.

Getting Information about your Tap Water

Q: How can I find out if my tap water is safe to drink?
A: Because of water's different sources and the different ways in which water is treated, the taste and quality of drinking water varies from place to place. Over 90 percent of water systems meet EPA's standards for tap water quality.

The best source of specific information about your drinking water is your water supplier. Water suppliers that serve the same people year-round are required to send their customers an annual water quality report (sometimes called a consumer confidence report).

Contact your water supplier to get a copy or see if your report is posted on-line.

For additional local drinking water information, visit the following EPA Web site:

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Q. How will I know if my water isn't safe to drink?
A: Your water supplier must notify you by newspaper, mail, radio, TV, or hand-delivery if your water doesn't meet EPA or state standards or if there is a waterborne disease emergency. The notice will describe any precautions you need to take, such as boiling your water.

Follow the advice of your water supplier if you ever receive such a notice. The most common drinking water emergency is contamination by disease-causing germs. Boiling your water for one minute will kill these germs. You can also use common household bleach or iodine to disinfect your drinking water at home in an emergency, such as a flood.

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Q. What's this new drinking water report that I've heard about?
A. Water suppliers must deliver to their customers annual drinking water quality reports (or consumer confidence reports). These reports will tell consumers what contaminants have been detected in their drinking water, how these detection levels compare to drinking water standards, and where their water comes from.

The reports must be provided annually before July 1, and, in most cases, are mailed directly to customers' homes.

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Q. How can I get my water tested?
A: If your home is served by a water system, get a copy of your annual water quality report before you test your water. This report will tell you what contaminants have been found in your drinking water and at what level.

After you've read this report, you may wish to test for specific contaminants (such as lead) that can vary from house to house, or any other contaminant you're concerned about.

EPA does not test individual homes, and cannot recommend specific laboratories to test your drinking water. States certify water testing laboratories.

You may call your state certification officer to get a list of certified laboratories in your state. Depending on how many contaminants you test for, a water test can cost from $15 to hundreds of dollars.

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Drinking Water Standards and Contaminants

Q. What is a drinking water standard?
A. Under the authority of the Safe Drinking Water Act (SDWA), EPA sets standards for approximately 90 contaminants in drinking water.For each of these contaminants, EPA sets a legal limit, called a maximum contaminant level, or requires a certain treatment. Water suppliers may not provide water that doesn't meet these standards.

Water that meets these standards is safe to drink, although people with severely compromised immune systems and children may have special needs.

For a more detailed description, read about how standards are set.

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Q. I don't like the taste/smell/appearance of my tap water. What's wrong with it?
A. Even when water meets EPA's standards, you may still object to its taste, smell, or appearance. EPA sets secondary standards based on these aesthetic characteristics (not health effects) which water systems and states can choose to adopt.

Common complaints about water aesthetics include:

  • temporary cloudiness (typically caused by air bubbles), or
  • chlorine taste (which can be improved by letting the water stand exposed to the air).

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Q. I'm worried about a specific drinking water contaminant [lead, Cryptosporidium, nitrate, radon, etc.]. What should I know?
Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. As long as they occur below EPA's standards, they don't pose a significant threat to health, although people with severely compromised immune systems and children may have special needs.

For more information about a specific contaminant, see EPA's fact sheets on drinking water contaminants, which have more detailed information on every contaminant EPA currently sets standards for and those EPA is considering setting standards for.

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Special Health Needs of People With Severely Compromised Immune Systems

Q. What if I have a severely compromised immune system?
A. Some people may be more vulnerable to contaminants in drinking water than the general population. People with severely compromised immune systems, such as people with cancer undergoing chemotherapy, people who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers.

EPA/Centers for Disease Control guidelines on appropriate means to lessen the risk of infection from Cryptosporidium and other microbial contaminants offer more detailed advice.

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Private Drinking Water Wells

Q. What should I do if I have my own drinking water well?
A: If you have your own well, you are responsible for making sure that your water is safe to drink. Private wells should be tested annually for nitrate and coliform bacteria to detect contamination problems early. Test more frequently and for other contaminants, such as radon or pesticides, if you suspect a problem. Check with your local health department and local public water systems that use ground water to learn more about well water quality in your area and what contaminants you are more likely to find.

More information is available on EPA's private drinking water wells Web site.

You can help protect your water supply by carefully managing activities near the water source, to find out how visit EPA's Source Water Protection Web site.

The organization Farm*A*Syst/Home*A*Syst Exit EPA Disclaimer provides information to help farmers and rural residents assess pollution risks and develop management plans to meet their unique needs.

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Bottled Water

Q. What about bottled water?
A: Bottled water is not necessarily safer than your tap water. EPA sets standards for tap water provided by public water systems; the Food and Drug Administration sets bottled water standards based on EPA's tap water standards.

Bottled water and tap water are both safe to drink if they meet these standards, although people with severely compromised immune systems and children may have special needs.

Some bottled water is treated more than tap water, while some is treated less or not treated at all. Bottled water costs much more than tap water on a per gallon basis. Bottled water is valuable in emergency situations (such as floods and earthquakes), and high quality bottled water may be a desirable option for people with weakened immune systems.

Consumers who choose to purchase bottled water should carefully read its label to understand what they are buying, whether it is a better taste, or a certain method of treatment.

More information on bottled water is available from the International Bottled Water Association, Exit EPA Disclaimer which represents most US bottlers.

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Home Water Treatment Units

Q. What about home water treatment units?
A: Most people do not need to treat their drinking water at home to make it safe. A home water treatment unit can improve water's taste, or provide an extra margin of safety for people more vulnerable to the effects of waterborne illness:

Consumers who choose to purchase a home water treatment unit should carefully read its product information to understand what they are buying, whether it is a better taste or a certain method of treatment. Be certain to follow the manufacturer's instructions for operation and maintenance, especially changing the filter on a regular basis.

EPA neither endorses nor recommends specific home water treatment units. EPA does register units that make germ-killing claims.

No single unit takes out every kind of drinking water contaminant; you must decide which type best meets your needs.

For help in picking a unit, contact one of the following independent non-profit organizations:

Both NSF International and Underwriters Laboratories Inc. test and certify home water treatment units. The Water Quality Association classifies units according to the contaminants they remove as well as listing units that have earned their “Gold Seal” approval. Water treatment units certified by these organizations will indicate certification on their packaging or labels.

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Drinking Water Sources and Protection

Q. Where does my drinking water come from?
A. Drinking water can come from either ground water sources (via wells) or surface water sources (such as rivers, lakes, and streams). Nationally, most water systems use a ground water source (80%), but most people (66%) are served by a water system that uses surface water. This is because large metropolitan areas tend to rely on surface water, whereas small and rural areas tend to rely on ground water. In addition, 10-20% of people have their own private well for drinking water. To find the source of your drinking water, check your annual water quality report or call your water supplier. You can get more information about specific watersheds by visiting EPA's Watershed Information Network. You can also learn more about EPA, state, and other efforts to protect sources of drinking water.

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Q. How can I help protect my drinking water?
A: Drinking water protection is a community-wide effort, beginning with protecting the source of your water, and including education, funding, and conservation. Many communities already have established source water protection programs. Call your local water supplier to find out if your community participates. You can also support efforts to improve operation, maintenance, and construction of water treatment processes. States are now engaged in source water assessments, to work with communities to identify local sources of contamination. You can contact your state source water protection program to find out how to get involved in this process, or join a local group in Adopting a Watershed.

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For more information

Q. How many public water systems are there in the United States?
A. There are almost 170,000 public water systems in the United States. Visit EPA's page of water system facts and figures for more information.

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Q: Where can I get more information?
A: For more information on your drinking water you can:

You can also contact:

EPA has also prepared a citizen's guide to drinking water called Water on Tap: What You Need To Know.

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