What’s in My Water? Answers to FAQs

Thirsty? What could be better than a tall, cold glass of water?  But how much do you know about the contents of that glass? Recent media attention focused on water contamination has caused us to revisit this topic and seek expert answers to questions not answered elsewhere on the site. 


First, let’s get a little background about the water supply we depend upon:


-The Earth’s water supply is limited.   We cannot create new water.  As the Environmental Protection Agency (EPA) points out, “Whether our source of water is a stream, river, lake, spring, or well, we are using the same water the dinosaurs used millions of years ago.”


-Only 1% of the world’s water is potable.  Nearly 97% is salt water, and the other 2% is found in ice caps or glaciers.


-According to a 2009 CitizenTube video, about 1.1 billion people don’t have access to clean water. Food scientist Dr. Joe Regenstein provided us with the following example: “In China, the assumption is that the water is not safe to drink, so water for human consumption is always boiled.  If you ask for water in a restaurant, it is always served warm so that you ‘know’ it was boiled.”


-We cannot and should not want our drinking water to be completely “pure.”  Says the EPA, all sources of drinking water contain some naturally-occurring contaminants which are generally not harmful to those who consume it.  Removing all contaminants would not only be expensive and pointless, but, in some cases, it would make the water less good: “A few naturally occurring minerals may actually improve the taste of drinking water and may even have nutritional value at low levels.”


-“In general, the tap water in the U.S. is safe to drink,” says food process engineer Dr. TimothyBowser, “but persons with special health considerations (the elderly, very young, and those with weak immune systems) should be careful.”


Now, let’s move on to the FAQs.


Exactly what is water pollution?


Lenntech (a water treatment company) defines water pollution as “any chemical, physical or biological change in the quality of water that has a harmful effect on any living thing that drinks or uses water or lives in it.”  In addition, water may be called polluted if it’s unfit for a particular desired use.


What are the categories of water pollution?


Some websites divide water pollution into two categories:


1) natural or  man-made or

2) direct or indirect. Lenntech offers the following, more detailed, divisions:


Category:                                            Example(s) or explanation of harm caused:


Disease-causing agents…………............…bacteria, viruses, protozoa

Oxygen-demanding wastes………........…depletes oxygen, causes death of aquatic life

Water-soluble inorganic pollutants…....………acids, salts, toxic metals

Nutrients (nitrates and phosphates)………........deplete oxygen in water; can kill fish, babies

Organic compounds ……..................…..oil, plastics, pesticides; harmful to living things

Suspended sediment…………….........depletes light absorption; spreads dangerous compounds through water

Radioactive compounds ……………........….can cause cancer, birth defects genetic damage


Who regulates the water supply in the U.S.?


The nation’s water is regulated by the EPA mainly through the 1974 Safe Drinking Water Act.  The individual states also regulate the water supply.  About 170,000 public water systems are monitored for some 80 harmful substances (bacteria viruses, pesticides, strong acids, and some metals).  According to the EPA, the U.S. has “one of the best supplies of drinking water in the world…Tap water that meets federal and state standards is generally safe to drink.” However, the EPA says, “Threats to drinking water are increasing.”


What are some of the threats?


Short-term disease outbreaks and weather–related catastrophes can temporarily contaminate the water supply in a particular area.  When these problems occur, the news media inform people of proper precautions needed.


The EPA points out that the population keeps growing and there are a growing number of activities that can contaminate drinking water.  The EPA’s list of polluting activities is quite long and includes the following: chemicals that are improperly disposed of (such as industrial waste); fertilizers and pesticides; animal and human waste; pollutants such as cadmium, chromium, lead, and selenium; and drinking water not properly treated or disinfected. Included as sources of these discharges are the recreational boats, houseboats, and marinas that release solvents, gasoline, and raw sewage directly into rivers, lakes and streams.   And, as ironic as it may seem, some procedures used to disinfect water may end up making the water more harmful to drink.


Problems with water contamination vary from one region to another.  For example, food scientist Dr. Catherine Cutter points out that pyrite is a problem in Pennsylvania and some other mining areas. When mining exposes the pyrite to air, iron oxide is produced; when it gets into the rivers or other bodies of water, it makes them more acidic, which is harmful to aquatic life. 


Some threats that recently or regularly receive media attention include the following:


Chromium:  Hexavalent chromium, a toxic metal, has been found in the water of some American cities at much higher levels than what the state of California has adopted as the safe level.  According to the Chicago Tribune, this discovery “is renewing a debate about dozens of unregulated substances that are showing up in water supplies nationwide.”  Dr. Bowser points out the following: “The EPA is currently re-evaluating the 0.1 mg/L limit in light of new evidence that indicates that chromium may be carcinogenic. I don’t think there is enough reliable information available to make any firm decisions beyond this point.”


Natural Gas: Many activist groups have been advocating against hydraulic fracturing (“fracking”), which injects a mixture of water sand, and chemicals into underground shale formations to gain access to embedded oil and gas.  The fear is that this process, used in many states, may contaminate drinking water obtained from wells.  EWG (the Environmental Working Group) and others are urging the government to ban fracking until more research has been done on its possibly harmful effects.


Medications: Water quality experts and environmental activists are increasingly concerned about water pollution from prescription drugs (such as the antibiotics given to humans and, prophylactically to factory-farmed animals), over-the-counter medications, as well as from sunscreen, perfume, and other personal care products, according to the Harvard Health Letter.   According to this publication, “Pharmaceutical pollution doesn’t seem to be harming humans yet, but disturbing clues from aquatic life suggest now is the time for preventive action.”


Lead: Lead in drinking water can cause a variety of adverse health effects on children and adults.  Lead is rarely found in source water, but it can enter tap water through corrosion of plumbing materials.  Homes built before 1986 are more likely to have lead pipes.  However, new homes are also at risk because even legally “lead-free” plumbing may contain up to 8% lead. You can find more information about lead by clicking here.  For additional information from the EPA, click here.


Radon:  Radon is a naturally-occurring, radioactive gas that may be found in drinking water and air. Water resources specialist Bryan Swistock explains: “Protection from radon starts with indoor air testing.  Radon in water is an air problem because the gas escapes into the air from the water.  If air radon is high, consider testing the water radon content, especially if you are on private water.” Those exposed to radon have an increased risk of getting cancer (especially lung cancer) over the course of their lives.  High levels of radon have been found in every U.S. state. Therefore, says Wikipedia, “testing for radon and installing radon mitigation systems has become a specialized industry within the past two decades.” 


Terrorists: If you’re looking for another water supply threat to worry about, here’s a doozy: terrorists could contaminate the water supply with toxic chemicals. 


The US Environmental Protection Agency provides a list of contaminants and their maximum allowable level. See http://water.epa.gov/drink/contaminants/index.cfm#Inorganic


In the U.S., how many people get sick from drinking water annually?


The CDC recently reported figures on drinking water illnesses from 2007-2008.  A total of 24 states and Puerto Rico reported 36 outbreaks that were associated with drinking water.  These outbreaks caused illness among at least 4,128 persons and were linked to three deaths.  The illnesses involved mostly gastrointestinal or respiratory symptoms.  The outbreaks were associated with untreated or inadequately treated ground water.  The report said, “…contamination of ground water remains a public health problem”


Does boiling water guarantee that all pathogens are killed and the water is safe to drink?


“Boiling water for one minute kills the microorganisms that cause disease,” according to the EPA.  Dr. Regenstein points this out: “Boiling will not destroy botulism spores, but, even if they happen to be present, they are unlikely to emerge from their spores and produce toxins, so they should not be of concern. As practical matter, water for all but young children is probably okay after boiling. The key is to get it to the boiling point.”   Dr. Bowser provides this advice from The Boy Scouts of America: boiling water to a rolling boil with bubbles a half inch in diameter rising from the bottom of the pot will kill microorganisms no matter how high the altitude.   


Keep in mind that boiling will not make impurities such as lead or nitrates disappear.  In fact, boiling water will make any lead or nitrates in the water more concentrated.  


Should I have a filter on the tap water coming into my residence?  


Water specialist Brian Swistock gives this advice: “Don’t spend money on water treatment without knowing that a problem exists.  Public water systems are required to meet health-based standards, so treatment of them is normally limited to apparent problems relating to tastes, odors, or staining.  Simple faucet filters using carbon can be excellent to remove many of these aesthetic pollutants.  Any larger, more expensive treatment (like a water softener) should be based on a water test from an accredited water testing lab.” Reverse osmosis filters are often recommended because they filter out more impurities than other filters.  However, they may also filter out minerals that are healthy and/or improve the taste of the water. Further negatives: they are hard on the plumbing, and they waste water. 


Dr. Bowser says that he likes to filter drinking water at his house. “My filter system is three-stage and includes a “rough” filter to remove any large particles (about 5 micron), a fine filter (0.2 micron) to remove bacteria, and a carbon filter to remove taste, odor and chemicals.”


How can I find out if my tap water is safe to drink?


Here is Swistock’s response: “If you are on public water supply, the testing is done for you.  [Households receiving public water should get an annual report about the source(s) and amounts of pollutants in their water.] If you are on private water supplies, you should absolutely be testing your water annually at least for coliform bacteria, pH, total dissolved solids, and any other local pollutants (determined by nearby land uses). If your drinking water comes from a household well, see section #7 of the EPA’s “Water on Tap” booklet. 


What can I do to help clean up the water we swim in, wash with, cook with, and drink?


Here are a few suggestions, some obvious, some not so obvious.


1.      Be careful where you dispose of trash.  Don’t throw either solid or liquid trash into a body of water. Material discarded into the sewage system on the streets often goes untreated into the local water system, says Dr. Regenstein.  Don’t throw paints or  oils  down a drain or into a toilet. 

2.      Buy nontoxic, biodegradable cleaning products.  Even though you have no way of knowing whether they’re really green or not, that’s the best guess.


3.      Put unwanted medications into the garbage, not a sink or toilet. Drugs that are consumed get into the water system via urine, but, if all discards were put into the garbage or brought to a take-back facility, that would help.


4.       Find out from your community how to properly dispose of hazardous materials. 


5.       Conserve water.  Fix water leaks. Take a quicker shower or a shallower bath.  Wear a clean shirt a second time before washing it.  If it’s going to rain tomorrow, don’t water your lawn tonight.  If you hand-wash your car, don’t keep the hose on the whole time.

6.      Use natural, rather than chemical, fertilizers. Chemical fertilizers get washed into the water supply by rain. The website Squidoo recommends compost, manure, and bone meal.


In the product section of this site, under beverages, Shelf Life Advice has Q/As on hard and soft water, bottled water, and many other water–related topics. To browse on Shelf Life Advice for additional information about water, click here. You can also use the site’s index or search box to reach water-related information.




epa.gov  “Water on Tap: what you need to know”


epa.gov “Lead in Drinking Water”


Bryan Swistock, Penn State Extension, Dept. of Forest Resources


Joe Regenstein, Ph.D., Cornell University, Dept. of Food Science


Catherine N. Cutter, Ph.D., Pennsylvania State University, Dept. of Food Science


Timothy Bowser, Ph.D., Oklahoma State University, Dept. of Biosystems and Agricultural Engineering


Chicago Tribune “Toxic metal stays in water” August 7, 2011, p.1.


Water-pollution.org.uk Water Pollution Guide “What Can You Do?”


squidoo.com “How to Decrease Water Pollution at Home”


lenntech.com “Water pollution FAQ Frequently Asked Questions”


Harvard Health Letter, “Drugs in the Water” June, 2011. 


Wikipedia, org.  “Radon”


citizentube.com “Water, Water Everywhere But Not a Drop to Drink”


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