Home/ Blog/ Healthy Living/

Is it Safe to Drink Tap Water?

Sep 25, 2015
By Lee Orsky

With endless advertisements for bottled water and filtering systems, it’s understandable why you might be suspicious of the H20 flowing from your kitchen tap. Although it’s true that the water in some cities contains trace amounts of pollutants, most healthy adults can still safely drink from the tap in most areas—and, in fact, tap water remains the most cost-effective, convenient way to stay hydrated.

Trendy bottled water brands continue to stock grocery shelves, but the environmental impact of all that plastic is significant: Aside from the massive supply of fossil fuel and greenhouse gas emissions powering manufacturing and shipping, the majority of plastic bottles end up in landfills rather than the recycling bin. For these reasons, many people find tap water to be the most appealing option.

While the quality of tap water varies by location, there are general principles that apply to most areas, as well as location-specific resources that can help you determine whether tap water is right for you.

What kind of contaminants could be in tap water?

According to the Environmental Protection Agency (EPA), all drinking water (including bottled water) may reasonably be expected to contain small amounts of some contaminants. But even if contaminants are present, that doesn’t necessarily mean the water you’re drinking poses any health risk. The EPA sets legally enforceable standards known as National Primary Drinking Water Regulations (NPDWRs), which  limit the levels of contaminants from industrial chemicals, bacteria and parasites, fertilizers, and other potentially harmful sources in drinking water.

There is a second set of non-enforceable guidelines known as National Secondary Drinking Water Regulations (NSDWRs) for contaminants that may cause cosmetic effects like skin or tooth discoloration, or contaminants that may alter the taste, odor, or color of drinking water. Water systems are not required to comply with NSDWRs, but some states may choose to adopt them as enforceable standards.   For detailed information on the EPA’s Maximum Contaminant Levels (MCLs), visit water.epa.gov/drink/contaminants.

How do I know if my tap water is safe?

Each year by July 1, you should receive an annual water quality report in the mail from your water supplier, telling you where your water comes from and what’s in it. Additionally, the EPA has the authority to monitor all public water systems and set enforceable health standards regarding the contaminants in drinking water.

Although the agency’s supervision doesn’t necessarily guarantee your water is free of all contaminants, it does ensure that the contaminants don’t pose any serious health risk. If there is a violation of standards, or the water supply becomes contaminated by something that can cause immediate illness, your supplier is required to promptly inform you and offer alternative suggestions for safe drinking water.

You can find the name, address, and phone number for your water system by browsing the list of systems in your state on the EPA website. Additionally, any community water system that serves more than 100,000 people is required to make its Consumer Confidence Report (CCR) available on a publicly accessible website.

Quirky Questions: Do I really need to drink 8 glasses of water per day?

Where does my city stand?

According to the National Resources Defense Council’s (NRDC) most recent report rating the water quality of the country’s major metropolitan areas, here’s where One Medical Group’s markets stood:

Boston: Good

The city has made major efforts to protect its watersheds.

Chicago: Fair

Lake Michigan is vulnerable to discharge from factories and other areas.

Los Angeles: Poor for imported water; fair for local water

Almost half of the city’s water comes from distant sources like the Colorado River, which are at severe risk for contamination.

New York: Good

Although the NRDC report doesn’t evaluate New York City’s drinking water, a 2014 Department of Environmental Protection report indicates the water quality is high and meets all health-related state and federal drinking water standards.

Phoenix: Poor

The city obtains 90 percent of its source water from areas vulnerable to depletion and contamination.

San Francisco: Good

Eighty-five percent of the city’s water comes from Yosemite’s Hetch Hetchy watershed and is well-protected.

Washington, DC: Fair

The city’s source, the Potomac River, is vulnerable to pollutant sources.

Who could be at risk if water is contaminated?

Most healthy people can drink tap water without any issue. But certain groups are more susceptible to adverse health effects if water becomes contaminated. These include:

  • Pregnant women
  • Very young children
  • The elderly
  • People with chronic illnesses
  • People living with weakened immune systems (because of HIV/AIDs, an organ transplant, chemotherapy, etc.)

If you fall into one of these high-risk groups, and you’re concerned about the risk of contamination, talk to your provider about whether you should take extra precautions or explore alternatives to tap water.

What are the alternatives to drinking tap water?

If you’re in a high-risk group or you live in a city where water quality is compromised, there are alternatives:

Bottled water

Bottled water may be a good temporary solution if your tap water is contaminated, but only if you choose a brand of verified quality. The FDA regulates bottled water as a food, which means it requires identification of the source and regulates allowable levels of contaminants, requires good manufacturing practice standards for boiling and bottling, and regulates labeling. However, the FDA doesn’t have the ability to oversee a mandatory testing program like the EPA does with public water suppliers; it can only order a recall once a problem has been found—so there is no guarantee that every bottle sold is safe.

In 1999, the NRDC conducted 1,000 separate tests of more than 100 brands of bottled water and concluded that bottled water isn’t necessarily any purer or any safer than city tap water, and some brands even contained elevated levels of arsenic, bacteria, or other contaminants.

In addition, bottled water costs hundreds or thousands of times more per gallon than tap water, so if you’re going to make the investment, choose a trusted brand. The International Bottled Water Association links to major brands’ quality reports.

You may also want to consider the environmental impact a long-term bottled water habit can have: Aside from the energy and fuel involved in manufacturing bottles, about 75 percent of bottles end up in landfills, lakes, and oceans, where they fail to decompose. If your tap water supply is not in danger, consider purchasing a refillable bottle instead.

Note: If you prefer carbonated bottled water but are concerned about its reputation for inhibiting calcium absorption, don’t be: There is no evidence to support this claim.


Filters and bottled water are about the same in terms of safety and cleanliness. There are four main types:

  • Activated carbon, which can remove certain organic contaminants
  • Ion exchange units, which can remove minerals like calcium and magnesium that make water hard
  • Reverse osmosis units, which can remove nitrates, sodium pesticides, and petrochemicals
  • Distillation units, which boil water and condense steam, creating distilled water

If you invest in a filter, choose one that removes the specific contaminants you’re concerned about. Also be sure the filter is independently certified by the Public Health and Safety Organization or a similar organization. Finally, maintain the filter at least as often as the manufacturer recommends.

Note: If you want to filter all contaminants from all of the taps in your home, you’ll need a “point-of-entry” filter. Otherwise, a “point-of-use” filter on the kitchen sink will do.


Boiling tap water can be effective, but it depends on the contaminant(s) being targeted. High temperatures can kill germs, but can’t affect lead, nitrates, or pesticides. In fact, boiling can actually increase the concentration of those contaminants because it causes the volume of water to decrease while the level of contaminants remains constant.

Here to keep you healthy. And informed.
Get 24/7 care over video chat from the comfort of home or wherever you go. Join today and experience primary care designed for real life, in-office and in-app.
Join Today
Lee Orsky, One Medical Provider
Read Provider Bio

The One Medical blog is published by One Medical, a national, modern primary care practice pairing 24/7 virtual care services with inviting and convenient in-person care at over 100 locations across the U.S. One Medical is on a mission to transform health care for all through a human-centered, technology-powered approach to caring for people at every stage of life.

Any general advice posted on our blog, website, or app is for informational purposes only and is not intended to replace or substitute for any medical or other advice. 1Life Healthcare, Inc. and the One Medical entities make no representations or warranties and expressly disclaim any and all liability concerning any treatment, action by, or effect on any person following the general information offered or provided within or through the blog, website, or app. If you have specific concerns or a situation arises in which you require medical advice, you should consult with an appropriately trained and qualified medical services provider.