Drinking Water Tests, Water Contamination Limits, Drinking Water Testing Procedures
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Water testing advice: how, when, and why to test water, what to test for in drinking water supply
Water potability testing guide - water bacteria test guide
How to conduct water tests, what water tests to order, how to avoid dishonest or cheating on water tests
Wells & water tanks, piping, supply: how to inspect, test, repair
Questions & answers about when, how, and why to test well water for contamination: advice for property or home buyers and property or home owners who use a private well for drinking water
This article gives advice on water testing for property or home buyers or home owners, with focus on a strategy for assuring the quality of well water by site inspection, property history investigation, and strategically-selected water tests for contamination. The articles listed on this water testing advice page will answer most questions about drinking water testing, focused on testing water supplied from wells, & water tanks as well as many other building plumbing system inspection or defect topics.
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Well Water & Drinking Water Testing Advice: How to Investigate for Water Contaminants at a New or Unknown Property or Well
Our complete list of water testing articles is at the end of this page. Readers needing details about each type of water test should see WATER TEST CHOICES & WATER TEST FEES. After testing your well water, see This article contains links to in-depth articles on inspecting, testing, and repairing problems with drinking water supply and wells, water supply pumps, water tanks, water testing and water treatment.
General advice on water testing when buying a rural property:
The minimum test for water potability elected by many property owners or buyers looks only at bacteria. Some government lenders require more extensive tests such as the FHA and Title-5 water potability testing series. Those and similar "water test package" deals offered by water testing labs can be a good way to spend your water testing dollars as they test for the most common contaminants found in well water in many areas.
Watch out for "False Negative" assurances that Well Water is "Pure"
But property buyers should beware of ordering water tests arbitrarily, Because of the enormous number of potential chemical contaminants that might show up in water, there is a risk of accepting a "false negative" result, that is, a risk of assuming that there are no contaminants in drinking water after a specific water contaminant tests shows a negative result .
It may simply be the case that a contaminant that is present was not detected because it was not within the scope of the tests performed.
Therefore to be more confident about the quality of water at a property whose water and land history may be unknown, we recommend a series of escalating steps in water testing and other investigative measures. At several points in the investigation process a property buyer or new owner may decide that the information obtained so far provides enough confidence, or that the information suggests that additional levels of water testing are appropriate.
Site investigation for well water quality concerns
This important step in investigating well water quality includes
A visual inspection for things that might raise a red flag: evidence of chemical, fuel, or fertilizer storage on the property or nearby at sites that drain onto the property, nearby industry (industrial chemicals), nearby orchards (pesticides) or farms (fertilizers) whose land drained across or onto the property.
Among the most basic observations will be the location of the well and its proximity to septic system drainfields, barns, livestock pens, or farm chemical storage tanks or fuel tanks. And of course the type of well (dug, driven point, steel well casing) and depth also have implications for the probability of contamination by surface runoff or subsurface contaminants.
Investigation by asking neighbors, the local health department, and nearby water testing laboratories to determine if they know of specific water quality problems that have been discovered in the neighborhood. This step can sometimes provide surprising payoff such as questions by one of our clients whose Pawling NY well had tested as "OK" for several contaminants. A neighbor pointed out that a paper company had for years dumped acetone and other waste chemicals in an empty field across the street from the client's well. Testing found unusual levels of acetone in the water - an uncommon contaminant as acetone is so volatile, and not something that anyone would have tested for without a clue from a helpful neighbor.
Professional investigation services are available from environmental inspection and testing firms who will research government data bases of known sources of water contamination, but watch out: such investigations may not disclose small local industries or contamination sources.
Choosing Specific Water Test Lab Tests for Water Quality
Informed by step 1 above, the minimum water test that is performed is a bacteria test or "water potability test". While the minimal "presence/absence" test is popular and inexpensive, the test gives a "go / no-go" result (there is or is not a coliform bacteria level at or above 1 colony forming unit (CFU) per 100 ml of water). Keep in mind that no water test assures a zero level of bacteria in water nor do health regulations require it. A more costly water test for bacteria provides an actual count of the bacteria level found, if above certain thresholds - this is a much more useful test as it is diagnostic both before and after attempts to correct a bacteria problem.
Bacteria testing does not itself assure anything about the presence or absence of chemical contaminants or aesthetic contaminants (silt, odors, hardness) in well water. But nevertheless, if a water test "fails" a bacteria test, because a common source of high bacterial levels in well water is the leakage of surface runoff into a well, that means that there is also a higher risk of the presence of other contaminants that might be found on the ground surface (pesticides, fertilizers).
Therefore even if a home owner/buyer decides to perform only the most minimal bacterial testing, the result can be a red flag that more thorough testing for other contaminants is in order.
Where a well is on or near farmland or orchards, water testing labs will often recommend one of two pesticide tests (depending on property age and whether or not it's appropriate to test for DDT or chlordane or newer pesticides, as well as tests that can detect common ingredients in fertilizers.
At a property in Dutchess County, NY, where we found a "permanently-parked" trailer that had been used by Terminix™ to store pesticides I was worried about possible storage leaks and thus pesticide contamination in the nearby well. Tests for pesticides found that there was no contamination of the well nor of soil around the trailer. The pest control company had been careful.
But a subsequent investigation of the property's history disclosed that a metal plating shop had been present in one of the buildings on the site. Tests found high levels of chromium contamination of soils, water, and even a nearby stream bed, resulting in a serious environmental contamination issue that involved the new property owner as well as local, state, and federal environmental officials.
Where the visual inspection or a study of the property history discovers specific potential sources of contamination, it makes sense to discuss these with the water test lab director to decide what tests are most useful to perform.
Watch out: this discussion has focused on well water quality - what is "in" the well water that may make it unsafe or unpalatable to drink. An equally important question is "does the well provide enough water" - a topic discussed at How Much Water is In the Well? and at How to Test Well Water Quantity
Tank Types Encyclopedia an encyclopedia of tanks in buildings, water tanks, fuel tanks, gas tanks, heating system expansion tanks, oil tanks, water cisterns, water pressure tanks, pressure booster tanks, antique, modern
WATER SOFTENERS & CONDITIONERS maintenance, adjustment, and water softener effect on drinking water and on septic systems - how to detect and correct hard water or minerals in water
Wells, Cisterns,& Springs types of sources of drinking water, what they look like, what goes wrong, what to do about it
Questions & Answers regarding this article
Questions & answers about when, how, and why to test well water for contamination: advice for property or home buyers and property or home owners who use a private well for drinking water
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1-Bromo-3-chloro-5,5-dimethylhydantoin (C5H6BrClN2O2) is produced world-wide and is also used in cleaners and bathroom disinfectants and deodorizers. Here is an example MSDS for this product, provided by Leisure Time
"Bacteria in Drinking Water" - "Chlorine," Karen Mancl, water quality specialist, Agricultural Engineering, Ohio State University Extension. Mancl explains factors affecting the effectiveness of chlorine in water as a means to destroy bacteria and other microorganisms. OSU reports as follows:
Chlorine kills bacteria, including disease-causing organisms and the nuisance organism, iron bacteria. However, low levels of chlorine, normally used to disinfect water, are not an effective treatment for giardia cysts. A chlorine level of over 10 mg/1 must be maintained for at least 30 minutes to kill giardia cysts. -- http://ohioline.osu.edu/b795/index.html is the front page of this bulletin
"Chemicals and Our Health", Nicholas D. Kristof, New York Times, 16 July 2009, p. 27. This outstanding editorial calls for improvements in public health policy to address phthalates and other environmental contaminants from common chemicals and products in everyday use. - DJ Friedman
Crystal Clear Supply provides portable ceramic water filter purifiers and portable reverse osmosis water treatment equipment - see http://www.crystalclearsupply.com/category_s/7.htm
Endocrine Disruptor Exchange, Dr. theo Colborn (also see Our Stolen Future). From that website: The Endocrine Disruption Exchange, Inc. is the only organization that focuses primarily on the human health and environmental problems caused by low-dose and/or ambient exposure to chemicals that interfere with development and function, called endocrine disruptors. ... TEDX's work focuses on the endocrine system, which is the exquisitely balanced system of glands and hormones that regulates such vital functions as body growth, response to stress, sexual development and behavior, production and utilization of insulin, rate of metabolism, intelligence and behavior. Hormones are chemicals such as insulin, thyroxin, estrogen, and testosterone that interact with specific target cells. The interactions occur through a number of mechanisms, the easiest of which to conceptualize is through a lock and key arrangement.
Giardia exposure limits for drinking water: see www.mass.gov/dep/water/drinking/standards/giardia.htm is the current regulatory exposure limit (your minimum target for
sterilization)
Health Effects of Chemical Contaminants in Drinking Water, US Environmental Protection Agency,
Hydrogen peroxide: Wikipedia on history of use of hydrogen peroxide: Information on Hydrogen peroxide as a sterilant is in Wikipedia at en.wikipedia.org/wiki/Sterilization_(microbiology) HO2 has been
used for a long time, including by vaporization for sterilizing freeze dryers.
Hydrogen Peroxide warning: US FDA Warning about drinking hydrogen peroxide: www.truthorfiction.com/rumors/h/hydrogen-peroxide.htm This article cites a 2003 entry in Journal
of Food and Science on using Hy.Perox to sterilize vegetables, referring to E.coli - NOT to Giardia.
Iodine: "Do Iodine Water Purification Tablets Provide an Effective Barrier against Cryptosporidium parvum?", Starke, Jeffrey A., Bowman, Dwight D., Labare, Michael, Fogarty, Elizabeth A., and others, Military Medicine, 25 October 2001 [possibly a later version of this article appeared in 2005 -DF] http://www.amsus.org/military medicine/milmed.htm
Ohio State University article on the concentration of chlorine necessary to act as an effective disinfectant, and the effects of the water's pH and temperature: See http://ohioline.osu.edu/b795/b795_7.html for details.
Our Stolen Future: Are We Threatening Our Fertility, Intelligence, and Survival?--A Scientific Detective Story, Theo Colborn, Dianne Dumanoski, John Peter Meyers. Plume-Penguin Publishing, 1997, ISBN 0-452-27414-1., ISBN13: 9780452274143. This book is a seminal work on endocrine disruptors (chemical contaminants having impact at extremely low levels in the environment).
Recommended by Daniel Friedman, this book is a critical update to the landmark Silent Spring by Rachel Carson and discusses the effects of minute trace amounts of chemical contaminants in the environment. The text "Identifies the various ways in which chemical pollutants in the environment are disrupting human reproductive patterns and causing such problems as birth defects, sexual abnormalities, and reproductive failure. Reprint. Tour. NYT."
Amazon.com Review: By O T (Ontario, BC) - 'Our Stolen Future' is a great introduction to one of the most important scientific discoveries in our time. Having recently completed a thesis project at university on Endocrine Disruptors, I have reviewed hundreds of papers on the subject. This book is a good clear overview of the scientific literature on EDs. The authors are experts - Theo Colborn is largely responsible for creating the field by bringing together diverse researchers so they could see the big picture of their work. Many of the principle investigators are interviewed and quoted at length on the way chemicals participate in and interfere with delicate hormonal systems in animals (including humans). The major accomplishment of the book is to make an easy-to-follow story out of complex research. Many resources are available to help you assess the reliability of this story, and the best thing to do if you have any doubts is read review articles in scientific journals (which are easier to understand than technical papers). The Physicians for Social Responsibility (PSR) have a guidebook for health-care professionals on Endocrine Disruptors, and the US EPA has many reports on the matter. Beware of people or websites who try to 'debunk' this book (or the science behind it) by simply declaring it false, flawed or disproven. There is far too much supporting research for so simple a refutation.
OPINION: Significant and discussed in this book is the observation that at certain critical points in the development of animals, presumably including humans, exposure to extremely low levels of endocrine disruptor chemicals (EDC's) (such as BPA - Bisphenol-A or BPA, Diethylstilbestrol - DES, dioxins, PCBs, and chemicals used in the production of certain cleansers, dyes, flame retardants, plastics, pesticides, white papers ) perhaps just a few molecules, or in the parts per trillion, is sufficient to cause disruption of the animal's development, including proper sex differentiation, or the lack of it that produced androgynous ducks unable to reproduce under such conditions.
A endocrine disruptor is a synthetic chemical compound that mimics natural hormones when it is taken into the body of a human or other animal. It "disrupts" the endocrine system by turning on or off normal chemical signals that in turn can affect normal hormone levels, bodily functions, and significantly, the development of embryos. Further, unlike naturally occurring hormones ingested, for example from plants (phytoestrogens), synthetically-generated hormones accumulate in the body and can have a half-life of decades or longer.
One significance of this finding includes the observation that an important medical effect that occurs with exposure to chemicals in extremely low concentrations means that experiments to test for correlations between chemical exposure and subsequent serious medical problems will be deeply flawed if, for example, the experimental design does not include testing for the presence of the chemical at extremely low levels. A related concern is that even if harmful effects from exposure to extremely low concentrations of an endocrine disruptor are occurring, teasing out and proving that relationship can be also extremely difficult.
Silent Spring, Rachael Carson, Mariner Books; Anv edition (October 22, 2002), ISBN-13: 978-061824906.
Amazon.com Review:
Silent Spring, released in 1962, offered the first shattering look at widespread ecological degradation and touched off an environmental awareness that still exists. Rachel Carson's book focused on the poisons from insecticides, weed killers, and other common products as well as the use of sprays in agriculture, a practice that led to dangerous chemicals to the food source. Carson argued that those chemicals were more dangerous than radiation and that for the first time in history, humans were exposed to chemicals that stayed in their systems from birth to death. Presented with thorough documentation, the book opened more than a few eyes about the dangers of the modern world and stands today as a landmark work.
US EPA: list of drinking water contaminants: see http://www.epa.gov/safewater/contaminants/index.html
UV light: This patent application for UV light sterilization www.patentstorm.us/patents/6565803.html Lists good references on water
purification for Giardia et als
Cheating on water tests: Testing Water for Real Estate Transactions - make sure your water test is valid
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
When Technology Fails, Matthew Stein, Chelsea Green Publisher, 2008,493 pages. ISBN-10: 1933392452 ISBN-13: 978-1933392455, "... how to find and sterilize water in the face of utility failure, as well as practical information for dealing with water-quality issues even when the public tap water is still flowing". Mr. Stein's website is www.whentechfails.com/
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Arsenic in Drinking Water