The Bottom Line

Water (H2O) can dissolve or suspend many substances: those that are beneficial to health and those that are actively harmful.
All drinking water, whether it is from a municipal supplier, a private source (well, spring, lake, etc.) or a bottled water provider will contain some contaminants, and the contaminant levels and types can change over time. 
Regulations in developed countries ensure that municipal water is treated to reduce levels of the most common and harmful contaminants to levels that are as safe as possible within cost constraints and the necessity of moving the treated water through miles of pipes.  Overall, municipal tap water in developed countries is safe for the vast majority of citizens and has saved countless lives over the alternative of drinking untreated water.  Levels of harmful contaminants that remain after treatment (or are added during treatment) may increase the risk of health problems for a very small number of individuals who drink the treated tap water.
Certain elements of the population, young children, pregnant women and the elderly and immunocompromized,  may be more susceptible to harm by water contaminants than the rest of the population.
Everyone will have different levels of comfort with the contaminants that are found in their drinking water - whether the water is from a private or a municipal company - or from a well or private source. 
Once you understand the contaminants that are (or might be) in your drinking water and properties of the various treatment methods, you will be able to make an informed decision (based on your comfort level) whether to drink your untreated tap water or invest in a treatment method to raise your water quality.  Hopefully your decisions will be based on knowledge, understanding and critical thinking, and they will not be a reaction to proclamations of some scare-monger or scam artist trying to sell you a product you may not need or that would not be effective.

Introduction To Water Quality Issues:

Water has been called the universal solvent because so many substances will dissolve in it.  Water also can carry many materials in suspension.  Unfortunately, water is not particularly selective in which compounds become dissolved or suspended.  The water that dissolves your coffee or tea and sugar in the morning or that you use to reconstitute your orange juice or infant's formula might also have dissolved some atoms of lead from the pipes in your home or picked up a microgram of 2,4 D from the farm upstream from the filtration plant.  If your water is chlorinated it almost certainly contains a few micrograms of chloroform (a byproduct of the disinfection process).

The question you need to ask is not, "does my tap water contain contaminants" - all water outside of laboratory distilled, deionized water does.  The real questions are, "what are the contaminates in my water, what are their concentration levels, and do they pose short or long term health risks at those levels."

Finding answers to these questions may not be easy.  The answers depend on where you live (country, city, surrounding land use, etc.), the primary source of your drinking water (confined or unconfined aquifer or surface water), your water supplier (private or community well, small or large municipal water system), and what is happening at any moment as your water travels from its source through the treatment/distribution system to your faucet.

Water that is reasonably contaminant free (and safe) one moment can become dangerously contaminated the next because of accident, neglect, or some natural event.  One of the most notorious recent examples of water that was safe one day and dangerous the next was during the summer of 1993 in Milwaukee when one-fourth of the people living in the metro area (over 400,000) became ill with cryptosporidiosis.  According to the 1996 Houston Chronicle series, Tapwater at Risk, the contamination of Milwaukee's water supply was a combination of natural events (heavy rains) and accident (improperly installed monitoring equipment) that allowed the parasite to pass though the city's purification system and into the distribution system.  In August of 1998 the citizens of Sydney Australia were told that Cryptosporidia had been detected in their municipal water supply.  Fortunately, despite a two-day delay in informing the population, there were apparently no reported cases of death or illness linked to the contamination.

Most government entities and water providers are extremely committed to supplying safe water to their citizens and/or customers.  Consequently, barring accidents, the majority of dangerous contaminants that are liable to be in the drinking water of most Americans (and people from other developed countries) are typically present in minute amounts.  They may contribute to health problems for some only after many years of exposure, making identification of the cause difficult, if not impossible.  Examples of this type of contaminant are low levels of lead (usually dissolved out of distribution pipes or plumbing fixtures in the home) which causes intellectual deficits in children, and trihalomethanes (a byproducts of chlorine disinfection) that have been linked to a slight, but significant, increase in the chance of getting certain cancers after 20 - 50 years of drinking chlorinated water.

Water treatment is not a simple issue.  It is, rather, a delicate balancing act.  There are ongoing and vigorous debates among the various groups interested in drinking water safety concerning the costs, the benefits, and the risks of every aspect of the water treatment and distribution business.  Anything that is done to treat municipal water costs money, provides the benefit of water that has reduced levels of the targeted contaminants, and decreases risk of disease from the targeted contaminants.  The treatment process may also add substances to the water that would increases risks of other disease for a few people who drink the water.

I suspect that in your reading you will find that in the United States and other countries, there are many committed people who are doing  a good job to ensure that the water delivered to your home is safe for drinking.  These are scientists who are trying to figure out the effects of various chemicals and pathogens on the human body or discover better treatment technologies, government regulators who try to identify, monitor, and regulate the amount of certain contaminants allowed in water, and professionals in the water industry who strive to deliver safe, quality water to their customers.

You will also discover that 'the system' does not always work.  Accidents happen, mistakes are made, systems wear out, toxic chemicals are released into the environment to find their way into the surface and ground water, regulators fail to regulate, population growth in a region puts more stress on a water system than it can handle, and any number of other weak links in the chain of processes that must function properly to deliver safe water to your faucet.  In February 2011 celebrity physician, Dr. Mehmet Oz, aired a series entitled, How Safe Is Your Drinking Water (Parts 1, 2, 3, 4 can be viewed online - the 4th episode discusses fluoridation).

Should You Be Concerned About Your Drinking Water?

So, are there reasons to be concerned about your drinking water safety?  Your answer to that question must depend on the results of your own research and your own tolerance for risk.  The site links listed below and information in the other pages at this site contain a tremendous amount of information on water quality.  You might also want to contact your water provider and obtain a "Treated Water Quality Summary Report" (The Water Quality Reports from Denver Water are a good example of what to request.  If you use well water you should have your water tested periodically to make certain that it does not contain significant levels of harmful contaminants.

From everything I have read, people in the US who have the most reasons to be concerned about their water are those served by small water treatment plants - particularly in agricultural regions of the country or areas with a number of industrial plants.  Also, anyone using water from a shallow well should keep a close eye on their water's quality - again, the most common areas of concern would be in agricultural or industrial areas.  This is, of course, not to say that all small water treatment plants or shallow wells will have contaminated water.  Nor does it mean that all water from large municipal treatment plants or deep wells will be free of harmful contaminant.  The Environmental Protection Agency's Safe drinking water information system will allow you to locate your drinking water supplier and view its violations and enforcement history since 1993.

Am I concerned about the quality and safety of my tap water?  Mildly concerned, yes --- Panicked, no.  I live in Denver, Colorado, and my family and I use municipal water supplied by Denver Water.  The taste of their water is excellent (hardly a taste of residual chlorine) and all of the harmful chemicals for which they test fall well below the Environmental Protection Agency Maximum Contaminant Level (or MCL) (most are below the levels of detection).  Despite the good taste and safe test results of our water, my research into drinking water issues convinced me to purchase a high quality water filter for the following reasons:

Populations at Higher Risk from Contaminated Drinking Water

Risks to: Children | Pregnant Women | Elderly and/or Immunocompromised

Children and the Risks of Contaminated Water:
The following excerpt from a report entitled Just Add Water from the Environmental Working Group by Brian A. Cohen, Richard Wiles, Erik D. Olson, and Chris Campbell, should help families recognize the importance of drinking pure, contaminant free water.

(End of excerpt)

Specific Water Contaminants of Concern for Children:
National Resources Defense Council - Our Children At Risk
EPA - Children and Drinking Water Standards - includes list of Contaminants to Which Children May Be Particularly Sensitive 


Specific Water Contaminants of Concern During Pregnancy:

There are ongoing studies that implicate a variety of other drinking water contaminants as possibly causing problems with pregnancy or the developing fetus:


Risks to the Elderly and/or Immunocompromised: Water Treatment Suggestion for High Risk Groups

Drinking Water Treatment Strategies

It is possible, though thankfully rare, for harmful bacteria or other pathogens to find their way into drinking water from a municipal water source. If these organisms are in the water illness can occur.  If tap water is regularly suspected to contain harmful pathogens, there are several point of use treatment options that can be considered for home drinking water if on a municipal water system.

Distillation and ozone are probably more expensive options than filtration and UV treatment.

If you are on on a well and suspect (or have found) biological contamination, point of entry disinfection might be the most economical solution for bacterial or viral contamination.

Bottled water is a good emergency source of safe drinking water, but often, by the time a problem has been discovered and the 'emergency boil' or 'do not drink' order has been issued, many people have already been exposed to the contaminated water.  A better solution when you suspect that municipal water (or well water for that matter) is or may become unsafe, is to install and maintain a permanent treatment system for all water consumed in the home (including tooth brushing).  Individual-size bottles can be carefully cleaned and filled with the treated water to drink away from home.

* Please be advised that the information on this page and on this site is for general educational information only and is NOT intended to make any specific health claims or recommend any specific treatment method or preventative advice for any health issue or problem.  Consult your physician or a health specialist for specific steps to take for your specific health or nutrition requirements!

    Copyright � 2005, Randy Johnson. All rights reserved.


Updated April 2015