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EWG's Tap Water Database

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Frequently Asked Questions

1. What is the purpose of EWG’s National Tap Water Database?

EWG developed our National Tap Water Database because we firmly believe that everyone has the right to know what's in their tap water. While the government requires utilities to give you some information, often the reports they share don't tell the full story.

Our database is currently the only free online consumer resource that analyzes tap water quality purely with respect to human health. Users can search by zip code to find their water utility, see the detected contaminants in their water, and learn how the levels of contaminants in their water compare to state and national averages and health guidelines. Through user-friendly displays, EWG’s database educates consumers about chemicals detected in their tap water, highlighting if these chemicals were found above levels that scientists deem safe and describing the associated health effects. The database, which is linked to our water filter guide, also makes it easier for consumers to avoid many of these contaminants by helping them find filtration devices and systems that have been certified to remove specific contaminants.

2. How does EWG’s Tap Water Database compare to my local water utility’s Consumer Confidence Report?

Here’s a list of major differences between the two:

  Consumer Confidence Reports EWG’s Tap Water Database
Testing Details Most show yearly averages for contaminants detected, which can hide seasonal spikes in pollution. Gives a precise picture of water quality throughout the year, listing full test results for each pollutant.
Safety Levels Compare pollution to regulatory limits, which are often based on political and economic compromise, not fully protecting public health. Focuses solely on health, comparing pollutants to levels scientists say are safe for everyone, including babies and pregnant women.
Number of Contaminants Often show only detections of federally regulated contaminants and some others the EPA wants data on. More than half of the contaminants detected in tap water had no regulatory limit. Shows all test results for all contaminants, not just those with legal limits.
How Your Water Compares Don’t say how your water quality compares to that of other communities across the state and country. Compares test results for all pollutants to state and national averages.

3. Does the Environmental Protection Agency have a similar database available online?

Not really, but it should. In fact, the 1996 Safe Drinking Water Act Amendments require the EPA to produce such a public service. But more than 20 years later, the EPA still hasn’t made this data public in a readily accessible or easy to understand manner. EWG's Tap Water Database will continue to fill this important gap until the federal government steps up to protect American drinking water from pollution.

4. Where did the data in your database come from?

EWG requested water contaminant data from public and environmental health agencies in all 50 states and D.C. We then compiled nearly the 28 million records we received from 49 states and D.C. The database also includes water quality data collected as part of the EPA’s Unregulated Contaminants Monitoring Rule (UCMR3). EWG released the first version of the database in 2005, updated it in 2009 and then again in 2017.

5. How do the data in your database differ from the annual water quality report I receive from my water utility?

The water quality reports that utilities are required to give their customers present only a partial picture of what people are actually drinking. These reports contain average levels and ranges detected for most contaminants, but they do not show spikes in contaminant levels that may have occurred during the year.

The reports typically only contain information on federally regulated contaminants because water utilities are not required to include any additional monitoring data they might have collected. The EPA only requires utilities report regulated chemicals and those unregulated chemicals included in special, mandatory testing programs.

Most importantly, the annual utility reports do not list health guideline information or say whether some contaminants might have been found at levels that, while legal, may not be safe. Water utilities are only required to list violations of legal limits that are often much higher than the health guidelines.

6. Your database does not have any information about my water system. Where can I find this information?

Although the database is very extensive, EWG was not able to obtain data for every water utility in every state. If you seek water quality information for a system that is not in the database, you should contact that water utility directly. Start by requesting the annual "Consumer Confidence Report" to look at your system's compliance with federal drinking water standards. The largest utilities are required to post their CCR's online; other systems will provide a copy upon request. As described above, the annual reports tell only a part of the story. For more information, compare the levels detected by your utility to the EWG-identified health guidelines.

7. Is my tap water safe to drink?

Most municipal utilities provide water that gets a passing grade from the federal government. At the same time, most state and federal drinking water regulations allow greater amounts of contaminants in tap water than what scientists estimate to be safe. Additionally, there are many unregulated contaminants that end up in drinking water.

If you want or need better drinking water quality than what comes from the tap, EWG suggests that you purchase a home water filter certified to remove or reduce the contaminants found in your tap water. EWG has developed an extensive online guide to choosing a water filter that will help you determine which one is right for you.

8. My water has contaminants detected above health guidelines. What does this mean? Do I have to get a filter?

Health guidelines are defined by scientists as the amount of a contaminant in drinking water that is not expected to pose any risk to health. Tap water contaminants are not good for anyone, and they are especially of concern for vulnerable populations and during sensitive periods of development, such as pregnancy and early childhood. In these cases, filtering out water contaminants is a great idea. Even for healthy adults, water filtration is a good choice. While certain contaminants can only be removed with advanced water filtration systems, if your water has contaminants detected above health guidelines, a simple countertop carbon filter is a great option.

9. I'm really concerned about my tap water quality. What should I do?

EWG suggests purchasing a home water filter. EWG has developed an extensive online guide to water filters to help you determine which one is right for you. If you are getting your water from a private well, EWG also recommends getting your water tested regularly by a state-certified drinking water laboratory.

10. Is bottled water safer than tap water?

Bottled water is not the answer and it is not always what people bargain for. In fact, reports show that some bottled water is just tap water filtered in some cases and untreated in others. The problem with bottled water is that you are never sure exactly what you are getting. Unlike public water suppliers, bottled water manufacturers are not required by law to disclose the levels of any contaminants in their products. A 2012 EWG report found that four out of every five bottled waters analyzed did not publish results of water quality testing. In addition to water contaminants that could come from the source water, bottled waters may also be contaminated with plastic additives that can migrate from plastic packaging into the water. Many of these additives have not been fully assessed for safety by the FDA, the agency with oversight over food and beverage packaging.

However, in a few emergency situations, bottled water may be the appropriate choice, particularly if your water supply has been compromised to the point that a home water filtration system would not render your tap water safe to drink. Situations like these may happen after major storms or earthquakes, or may be due to catastrophic infrastructure failures. In cases such as these, choose bottled water that discloses the water source, treatment and results of water quality tests, and uses advanced treatment methods – like reverse osmosis and filtration – to remove a broad range of pollutants.

11. What kind of water filter should I buy?

It depends what you are looking for, which could include factors like overall cost, removal of specific contaminants, scale of water filtration or filter type. EWG has developed an extensive online guide to choosing a water filter to help you find a filter that meets your needs.

12. Should I be concerned about lead in my tap water?

First, ask your water provider if tap water enters your home through a lead service line. Even if the pipes leading toward the house are not lead-based, there might be some lead in the household plumbing fixtures, so consider getting your tap water tested for lead. Testing is particularly important if you live in an area served by lead-based water lines; if your local water company has detected lead in your neighborhood; or, if you are a private well owner and lead has been detected in well water in your area.

If there is lead in your water, you can reduce the amount by flushing cold water pipes each morning, using only cold water for cooking and installing a home water filter. But these are just temporary solutions. The only permanent fix to chronic lead contamination is to replace lead-based water pipes.

For more information about lead in drinking water and tips to decrease your family’s lead exposure, read the “What about lead?” section in our database.

13. Where can I get my water tested?

There are numerous labs around the country that do water testing for common contaminants. We recommend that you choose one that has been certified by the state to test drinking water. The EPA’s website has additional information and resources to help you choose an appropriate lab.

14. Where does my tap water come from?

Drinking water sources vary greatly across the country, and even within communities. Water utilities may depend on surface water, including streams, rivers and lakes; or pump groundwater out of wells. Additionally, many water systems buy water from other water companies or large-scale water suppliers. For more information on where your tap water comes from, contact your local water utility.

15. Are some people more sensitive to water contaminants than others?

Yes. 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 people, and infants can be particularly at risk of infections. People that fall into this category should take special precautious with the water they drink and seek advice about drinking water from their health care providers. The EPA, jointly with the Centers for Disease Control and Prevention, published recommendations to help immunocompromised people take extra precautions for safe drinking water.

16. My tap water has a strange smell, taste or color. Should I be concerned?

Unpleasant smells, colors or tastes do not necessarily mean that your water is unsafe to drink. However, these can be important indicators of potential safety problems. EWG recommends that you contact your local water supplier to investigate these conditions.

If the smell, color or taste is related to excessive minerals in your water, a home water filter can help solve the issue. EWG has developed an extensive online guide to help you choose a filter that might help solve your problem.

Another source of an unusual water smell could be the growth of algae in the source water used by the water utility. Algal toxins cannot be removed by ordinary water filtration methods. If algal contamination is reported by your water utility – as happened repeatedly in lake Erie, which supplies water to the city of Toledo, Ohio – temporary use of an emergency bottled water supply may be necessary.

17. My water smells like chlorine. What should I do?

Each water system regulates its own use of chlorine to disinfect water. Especially after large rainstorms – when large amounts of plant and animal waste, sewer discharge and urban runoff can end up in the water – your water system may add more chlorine or other disinfectants to treat potentially larger numbers of disease-causing microorganisms. These disinfectants, while essential to protect public health from waterborne diseases, create carcinogenic disinfection byproducts. To deal with excess chlorine and disinfection byproducts, you may consider installing a home water filter specifically designed to remove these chemicals from drinking water. EWG has developed an extensive online guide to help you find the right one for you.

18. My community has issued a boil water alert. What does that mean?

Under the provisions of the Safe Drinking Water Act, water systems that serve more than 25 people are required to test their water regularly for a wide variety of contaminants. If a water system has issued a boil water alert, it has likely discovered one or more microbiological contaminants at levels exceeding those allowed by the EPA. The water system must then take appropriate corrective action, continue to monitor its water supply and notify customers when it has remedied the problem.

19. I’ve checked the database to see which chemicals were detected in my tap water and purchased an appropriate water filter. What else can I do to make my water better?

One of the best things you can do to make your water better is to hold elected officials accountable. EWG has developed a list of suggested questions that you may use to contact those who may have a say in your water quality – from your city council all the way to the Oval Office. Be sure to urge leaders to invest in better water treatment technology, create sustainable funding for water system improvements, and protect source waters so that pollution does not get into your water in the first place.