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
one who is able to turn on a faucet and expect to fill their glass with
clean, safe water should visit the Peace Corps'
in Africa site.|
||Detour to a brief discussion about
fresh water abundance, surface
water, and ground water.
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.
receive and read water quality reports sent out by your water provider?
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
||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
The depth of a well is
not usually as important as the type of aquifer from which the well draws.
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
of contamination for wells or springs mostly in unconfined aquifers. The most common contaminants from septic systems tend to be
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, and
Information about private wells:
American Ground Water Trust
State Water Resources Control Board (pdf)
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.
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
Chlorinated Water and the Risk of Disinfection Byproducts:
your water Chlorinated?
||Most municipal water treatment plants use chlorine
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
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."
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
The quote from the EPA above tells only
part of the story. In addition to laboratory studies showing cancers
and reproductive problems in animals, there some evidence
based on epidemiological studies that implicates DBPs as contributing to
problems during pregnancy.
There is also epidemiological evidence
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
More information about epidemiological studies.
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:
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.
Age and the Risk of Lead Contamination:
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.
drinking water is most often a problem in houses that are either
very old or very new.
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
Great looking, smelling, and tasting water is no guarantee that you
have safe water!
Many contaminants, lead, mercury, E. coli, disinfection
byproducts - in
the majority of the harmful contaminants listed
below - have
no taste or smell, nor would they be visible in harmful
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.
Blue to Blue-green
Cloudy, or Milky
Reddish - orange
Dark brown to Black
Spots, & Sediment
Spots on clothing
Spots on dishes
Spotting, mottling, of
Red - brown slime
Black - brown slime
Reddish - brown
pitting of metal
sinks and fixtures
Sharp chemical Alkaline
Oil or gas
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
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.
Contaminants and Treatment Methods
Comparison of Drinking Water
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.
this table is too large for your screen, I have
broken it into two separate tables, one
covering the biological
and the other covering the
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.
Quality Association (WQA) also has a Table
of Water Contaminants, their health effects, and removal methods
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!
|Copyright © 2005 Randy Johnson. All rights reserved.
Updated November 2011