Drinking water information and resources, contaminants, health effects, treatment methods

 Risk Factors for Water Contaminants

What Conditions Increase the Risk of Having Certain Water Contaminants? The information on this page is particularly important if you have young children, or if you or a member of your family is pregnant or has a compromised immune system.

Drinking water concerns
Drinking water concerns Introduction
Drinking water concerns Concerns about water safety
Drinking water concerns Children and contaminated water
Drinking water concerns Pregnancy and drinking water contaminants

Drinking water contaminants
Drinking water concerns Introduction
Drinking water concerns Materials dissolved in water
- Inorganic
- Organic
Drinking water concerns Materials suspended in water
- Pathogens
- Asbestos
Drinking water concerns Interview excerpt

Risk factors for contaminants
Drinking water concerns Drinking water sources
Drinking water concerns Municipal providers
Drinking water concerns Private wells
Drinking water concerns Location of home
Drinking water concerns Chlorination and DBPs
Drinking water concerns High risk populations: pregnancy
Drinking water concerns Home age & lead
Drinking water concerns Use Sensory clues to identify contaminants

Drinking water concerns Importance of product certification
Drinking water concerns Things to consider
Drinking water concerns Methods:
Point of Entry (POE)
Point Of Use (POU)
- Boiling
- Distillation
- Reverse Osmosis (RO)
- Filtration
  * Sediment
   * Activated carbon
   * GAC
   * Solid block
   * Pore size
- Bottled water
- Ultraviolet (UV)
- Water softeners
- Ion exchange
- Whole House
'Altered' water
Drinking water concerns Comparison of drinking water treatment methods - chart
Drinking water concerns Comparison of long-term costs for water treatment
Drinking water concerns Emergency water treatment

Other water topics
Drinking water concerns Drinking Water Scams
  Alkaline Water
  Other Types
Drinking water concerns Masaru Emoto & Water Crystals
Drinking water concerns Distilled Water & Health
Drinking water concerns Water-Related Quotes
Drinking water concerns Bottled Water
Drinking water concerns Four Steps to determine the best water treatment method for you

Recommendations Recommendations
Recommendations Questions
Recommendations About Me

Recommendations links to drinking water related sites
bullet Source of Your Drinking Water
   Municipal water provider
   Private water supply - aquifers 
(well, spring, surface water)
bullet Where You Live
   Industrial area
   Agricultural area

bullet Chlorinated Water and the Risk of Disinfection Byproducts

bullet Home Age and the Risk of Lead Contamination
bullet Water Problem Table - Use sensory clues to identify common water problems
bullet Table of Contaminants and Treatment Methods
bullet A Four-Step Guide - Information on selecting a water treatment method for your specific situation.
The Bottom Line:
Water dissolves or suspends many substances Your water's source can help you understand what contaminants might be in your drinking water.
- Municipal water is treated to reduce regulated contaminants to levels that are considered relatively safe.
- Private water supplies (particularly from the surface and shallow wells in unconfined aquifers) can contain any number and type of contaminants and the only way to know what is in your water is with regular tests.
Water Contaminants can be beneficial or harmful to health Nearby industrial and agricultural activities can contaminate drinking water sources.
Municipal (public) water providers are required to test the treated water on a regular basis Chlorination and other disinfectants kill pathogens but introduce traces of contaminants (disinfection byproducts) that carry their own health risks.
Municipal (public) water providers are required to test the treated water on a regular basis The age of a home or other building can help determine contaminants that might be introduced into drinking water from the plumbing.
Municipal (public) water providers are required to test the treated water on a regular basis Some water contaminants (but not all that are harmful) can be identified by taste, odor &/or smell.
Municipal (public) water providers are required to test the treated water on a regular basis No treatment method is 100% effective at removing contaminants (distillation is close), and all treatment methods have associated costs and limitations.

Drinking Water Sources:

The geographic region where people live is an important contributing factor to both the quality and availability of fresh water.  This map shows the percentage of population with access to safe water by country.  Another interesting article from The Why Files takes a look at water availability in different regions of the world.  Every one who is able to turn on a faucet and expect to fill their glass with clean, safe water should read this report.

Detour to a brief discussion about fresh water abundance, the water cycle, surface water, and ground water.   This article contains many references to the water cycle, a natural process critical to replenishing our fresh-water supplies.

 If you are provided with municipal water, the responsibility for your safe drinking water lies with the water provider.  

  • Although water companies in the US and many other countries are strictly regulated and the treated water must meet certain minimum purity and safety standards, all water companies are not created equal.  You can reasonably assume that most are doing the best they can with the resources available to them - if for no other reason than to keep their name out of the evening news.
  • In general, though, the larger water companies (in the US anyway) have greater resources available to treat and distribute the water and maintain the distribution infrastructure.  And, because they serve more people, they are required to meet stricter regulations.
  • This is a list item
  • This is another list item
    • And it even works in nested lists
    • See?
  • And another
  • And yet another


Do you receive and read water quality reports sent out by your water provider?

The EPA has a page that describes the Consumer Confidence Reports that are porvided by public water companies every year.

The Safe Drinking Water Act of 1996 mandated that public water companies were to prepare annual water quality reports and make them available to all customers.

(NSF) also maintains a page that describes how to interpret consumer confidence reportsDrinking Water Quality Reports also has valuable information as does the Purdue Extension. 

 Some information for well owners or people who use surface water for drinking.  People with private water supplies are responsible for the safety of their own drinking water.  While all wells, springs, and surface water should be tested regularly, there are some situations where it is critical to know what is in your water:

If you use surface water or water from an unconfined aquifer and have any sources of pollution nearby, you are at risk for contaminated water. 
If you or members of your family are at higher risk of health problems from contaminants, you should know what is in your water.
If the quality of your water suddenly changes - new taste, odor or color.

The depth of a well is not usually as important as the type of aquifer from which the well draws.  In general, well water from an unconfined aquifer is much more prone to contamination than water from a confined aquifer.  Click here to learn more about aquifers and the contaminant risks associated with each type.  For the teachers who are visiting: I discovered what appears to be a very interesting  groundwater model that demonstrates confined and unconfined aquifers, how water and contaminants move through aquifers, various soil structures, and watersheds.

Poorly designed or maintained septic systems are a potential source of contamination for wells or springs mostly in unconfined aquifers.  The most common contaminants from septic systems tend to be E. coli and nitrates, but if other chemicals are flushed into the septic system by you or your neighbors, they can become part of the ground or surface water pollutants as well.  another site.

Information about private wells:
 The Water Research Center
    private well owner help guide site
    private well owner booklet
    the Keystone Clean Water Team
    Insights into Baseline Water Testing
 American Ground Water Trust
 National Environmental Services Center
 California State Water Resources Control Board (pdf)

Water Testing:
If you use municipal water you should be able to obtain a water quality report yearly and, except for special circumstances, would probably not need to test your water.  If you use well, spring, or surface water, it is important to test your water periodically  for contaminants liable to be present in your water.  As discussed above, water quality from a water source can change over time - particularly in surface water or shallow, unconfined aquifers.  The University of Tennessee Agricultural Extension Service article, Safety of Private Water Supplies, has important suggestions and information about testing for the safety of your well water.

Where You Live:

Home Located in an Industrial Area:  
The range of possible industrial pollutants is extremely large. Important contaminants include heavy metals and many thousands of kinds of manufactured chemicals.  Water contamination can occur from:
  Emissions into the atmosphere that either settle onto or wash onto the earth's surface
     and from there into the surface or ground water.
  Waste dumps that leak into surface or ground water.
  Leakage from storage areas of chemical products or their precursors.
  Accidents and spills during transport of chemicals.
  Direct dumping of contaminants into surface water for disposal.

A recent movie that examines some consequences of industrial pollution is A Civil Action starring John Travolta.

Home Located in an Agricultural Area:
Farms can have many potential sources of pollution for the underlying water, including: manure lagoon, feedlot / barn, septic system, earthen silage pit, fuel storage tank, chemical storage area, chemical mixing area, dump or landfill, and fields on which fertilizers or pesticides have been applied.  For more information on farm wells, go to: Well Water Location.   In addition to the health effects of nitrates on children nitrates in drinking water have also been associated with other health problems

Chlorinated Water and the Risk of Disinfection Byproducts:

Is your water Chlorinated?
Most municipal water treatment plants use chlorine or chloramine to disinfect the water before it leaves the treatment plant and/or keep the water biologically safe during the distribution process.  Many well users also use chlorine to disinfect their water.
Chlorine, while an excellent disinfectant, reacts with organic material in the source water to produce a group of chlorinated organic compounds collectively known as Disinfection Byproduct (DBPs).  According to several EPA articles
"While disinfectants are effective in controlling many microorganisms, they react with natural organic and inorganic matter in source water and distribution systems to form DBPs. Results from toxicology studies have shown several DBPs to be carcinogenic in laboratory animals. Other DBPs have also been shown to cause adverse reproductive or developmental effects in laboratory animals. Several epidemiology studies have suggested a weak association between certain cancers (e.g., bladder) or reproductive and developmental effects, and exposure to chlorinated surface water. More than 200 million people consume water that has been disinfected. Because of the large population exposed, health risks associated with DBPs, even if small, need to be taken seriously."
Chloramine use produces fewer regulated disinfection byproducts than chlorine disinfection, but that may just be because chlorine has been in use far longer and has been studied extensively.

The DBPs include Total Trihalomethanes (TTHMs) (including chloroform, bromodichloromethane, dibromochloromethane, and bromoform),  and Haloacetic Acids (HAAs) (dichloroacetic acid and trichloroacetic acid)

In 1979, the EPA set an interim Maximum Contaminant Level (MCL) for TTHMs of 0.10 mg/l (or 100 microgram/l) as an annual average. This applies to any community water system serving at least 10,000 people that adds a disinfectant to the drinking water during any part of the treatment process.  By 2002 the MCL for TTHMS will be lowered to 0.08mg/l (or  80 ug/l) and a MCL for HAAs will be set at 0.06mg/l

There is also epidemiological evidence suggesting a weak association between the consumption of chlorinated drinking water and the occurrence of bladder, colon, and rectal cancer (and possibly even some brain cancers).  

In epidemiological studies, investigators compare health effects in a population of people who drink water containing higher levels of DBS with a similar group of people who drink water with lower levels of DPS.  Estimates in the role of DBPs and cancer have changed over the years because it is extremely difficult to determine exposure levels to DBPs over decades and determine what the contribution of that exposure might have been to the development of some cancer.  This article provides some history of the process.  It is a tough balancing act between adding too little chlorine (resulting in more microbial contaminants and fewer DBPs), and too much chlorine (resulting in dead microbes and higher levels of DBPs).  The World Health Organization concluded, the risk of death from pathogens is at least 100 to 1000 times greater than risk of cancer from disinfected by-products and risk of illness from pathogens at least 10,000 to 1 million times greater More information about  epidemiological studies.

A 1996 study by King and Marrett concluded "that the risk of bladder cancer increases with both duration and concentration of exposure to chlorination by-products".  They found that those exposed to chlorinated surface water for 35 or more years had a 1.4 times increased risk of bladder cancer compared with those exposed for less than 10 years, and those exposed to an estimated THM level greater than 49 micrograms/liter for 35 or more years had 1.63 times the risk of those exposed for less than 10 years.

Populations At Greater Risk from Water Contaminants:
        Pregnant Women, Children, Elderly, Immunocompromised

Any person who requires water of a specific microbiological purity should follow the advice of their doctor or local health officials regarding the use and consumption of tap water treated by ANY purification system.

Home Age and the Risk of Lead Contamination:

The age of your home can be an important indicator of
  whether lead m100%t be a contaminant in your drinking water.

Most well or city water does not naturally contain lead. Water usually picks up lead inside
     your home from household plumbing that is made with lead containing materials. 
Lead-contaminated drinking water is most often a problem in houses that are either
     very old or very new.
  Plumbing installed before 1930 is most likely to contain lead.
  Lead solder was banned in the US in 1987, but the ban has not been universally adhered to. 
  New brass faucets and fittings can also leach lead, even though they are labeled "lead-free".
  Scientific data indicates the newer the home, the greater the risk of lead contamination.
More about lead and your drinking water here.

Contaminants and Sensory Clues:

 Great looking, smelling, and tasting water is no guarantee that you
      have safe water!

        Many contaminants, lead, mercury, E. coli, disinfection byproducts - in
            fact the majority of the harmful contaminants listed below - have
            no taste or smell, nor would they be visible in harmful quantities. 

      Click here to view more information about water safety and well

If your water normally looks, tastes, and smells good and then suddenly becomes cloudy (turbid) or acquires a bad smell or taste it may be an indicator that the purification process has failed.  Immediately begin using water filtered with a high quality filter, bottled water, or otherwise purified water until you have determined that your water is safe.  That would also be a very good time to consider looking for a permanent water treatment solution.

Water Problem Table
Identify Common Water Contaminants by Their Sensory Clues

Important Introduction

Blue to Blue-green
Cloudy, or Milky
Reddish - orange
Dark brown to Black

Deposits, Spots, & Sediment
Soap scum 
Bathtub rings
Scaly, whitish
Spots on clothing
Spots on dishes
Spotting, mottling,  of
Red - brown slime
Black - brown slime
Reddish - brown
Blue-green stains
Brown-red stains
Black stains
Blackening and
   pitting of metal
   sinks and fixtures
Gray stains
Yellow stains

Salty, brackish
Sharp chemical Alkaline
Salty, brackish
Sharp chemical
Sweet, perfume
Rotten eggs
Oil or gas
Musty, earthy


The Environmental Protection Agency (EPA) has several excellent sites that describe water contaminants.  The  EPA's Drinking Water Standards site gives you a list of the regulated contaminants, their maximum allowable contaminant levels, the main source(s) of the contaminants, and their health effects.  A more comprehensive EPA site is, What are the health effects of contaminants in drinking water?  

Have you ever been told that your household water is unsafe and to either boil your water before drinking it or to drink bottled water until the problem has been corrected?

Have you or a member of your family ever become ill from your home drinking water?

If you answer "yes" to either question, it would probably be a good idea to invest in a high quality water treatment system.  According to the National Primary Drinking Water Regulations: Public Notification Rule; Final Rule, Section 1414(c)(2)(C), The EPA regulations "require Public Water Services to distribute a notice within 24 hours to persons served for violations with potential to have serious adverse effects on human health from short-term exposure".  Considerable exposure to the contaminant can occur during that period.

Table of Contaminants and Treatment Methods

Comparison of Drinking Water Treatment Methods

I developed a Comparison Table listing different drinking water treatment technologies and the contaminants they remove to make it easier for you to determine which process, or combination of processes will be best for your particular drinking water situation.
If this table is too large for your screen, I have
    broken it into two separate tables, one
    covering the biological and organic
    contaminants, and the other covering the
    inorganic contaminants.  They should be
    easier to read on monitors set at 800 X 600.

I also developed another table that shows similar water treatment information in a somewhat different format that you might want to take a look at.  This table is geared mostly to point of use water treatment methods.

The Water Quality Association (WQA) also has a Table of Water Contaminants, their health effects, and removal methods

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 requirements!


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Copyright 2005 Randy Johnson. All rights reserved.

Updated November 2011