Tap water comes in many flavors. In fact, it can be so specific to each locality that some people consider it the secret ingredient in New York bagels and pizza. But unpalatable drinking water can prompt people to scramble for filters, trying to rid their water of the flavor of pennies, dirt or bleach.
Moreover, people may worry that funny-tasting tap water may carry dangerous substances or pathogens. There is evidence that tap water has been the likely source of some disease outbreaks, including Legionnaires’ disease and gastrointestinal illnesses, although, in many outbreaks, researchers can’t be sure of the culprit.
In any case, the link between how water tastes and what’s in it isn’t straightforward.
“Unfortunately, whether or not you can taste something, to my knowledge, is not highly correlated to whether or not there’s something to worry about,” Dr. Robert Wright, a pediatrician and chair of preventive medicine at Mount Sinai School of Medicine in New York, said in an interview with Live Science.
For example, arsenic, nitrates and infectious agents, such as bacteria and viruses, don’t have a strong flavor but can cause serious health issues. Another dangerous substance in water, lead, doesn’t have a very obvious taste, or can sometimes even taste sweet. [Tip of the Tongue: The 7 (Other) Flavors Humans May Taste]
Researchers do know that the likely origins of many tap water tastes are mostly harmless beyond being unpleasant. However, there are certain flavors that can signify an issue in the water supply. If people taste those flavors, or notice any sudden or extreme changes in their drinking water’s taste, they should notify authorities, experts told Live Science.
Where different tap water tastes come from
Water systems can be very complex, and tracing the causes of different tap water flavors can be just as complicated. When we turn on the tap, “It’s not magic. It comes from somewhere,” Wendy Heiger-Bernays, an associate professor of environmental health at the Boston University School of Public Health, told Live Science.
About 15 percent of people in the United States use well water, according to the U.S. Environmental Protection Agency. This means that their water does not come from a municipal source but from a private well. People who have wells must take it upon themselves to test their water regularly, which can be costly, Wright said.
The other 85 percent of the U.S. population gets their water from municipal systems. Whereas almost all well water is groundwater, municipal water may come from surface sources, such as rivers and lakes, or a combination of sources. This water takes a long journey, from a treatment plant, through pipes underground and often below city streets, and finally through the pipes in homes. Features of all of those pipes, as well as the source of the water itself, can influence the final taste of what comes out of the tap.
But the flavor of water isn’t usually a taste issue in the strictest sense. “Most tastes are almost entirely the odor that [comes from] the water,” said Theresa Slifko, a manager at the water quality laboratory at the Metropolitan Water District of Southern California (MWD). MWD has a panel of four to five people who both taste and sniff their water supplies, because they can often detect odor and flavor at much lower levels than other analytical methods. [8 Strange Things Scientists Have Tasted]
Undesirable flavors include earthy, sulfuric, chlorine, metallic and swampy. These flavors may originate from algae, bacteria, disinfectants, wildfires, minerals and decaying vegetation, but for the most part, these things are not generally dangerous to people’s health.
What different tastes mean
Here is a look at some of the flavors of tap water, and what causes them.
Fishy, earthy, dirty, moldy, musty: The likely reason for any of these tastes is algal blooms in the source water, and for that reason, this taste may be more apparent in spring or other times when blooms are more likely, Heiger-Bernays said. Municipal water is treated, so there shouldn’t be any algae in it, but the taste may linger, she said. Another reason for this flavor could be bacterial growth within the water system or even a person’s own sink, all of which are usually harmless. [Top 7 Germs in Food That Make You Sick]
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