When to Re-Test or Not Re-Test a Drinking Water Well InspectAPedia® -
When a well fails a water test, under what conditions do we just re-test?
When is re-testing a drinking water well useful and when is it a waste of time and money?
What to do various high or low bacterial levels mean when a well fails a potability test?
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This article explains when it is useful to re-test a drinking water well after it has failed a bacteria test. We explain how to interpret and thus act on the results of water tests for various types of water contamination. This series of articles explains many common water contamination tests for bacteria and other contaminants in water samples. We describe what to do about contaminated water, listing common corrective measures when water test results are
unsatisfactory.
We include water testing and water correction measures warnings for home owners and especially for home buyers when certain conditions are encountered, with advice about what to do when these circumstances are encountered. Various treatment methods for contaminated water are reviewed and the pros and cons of each are discussed.
Acting on Unsatisfactory or Contaminated Water Test Results - Advice for Home Buyers & Home Owners
Handling Failed Wells that Pass a Second Water Test: What to do if water passes after disinfection
When will shocking the well actually cure a problem?
If the well water contamination level was a relatively low bacteria count and was caused by an unsanitary growth in plumbing equipment this treatment can "correct" the problem.
If the contamination was a relatively low to modest count and is caused by a persistent source of contamination, this treatment can appear to correct the problem by killing off bacteria. But the problem can recur.
When does well disinfection not work?
If the contamination is from a major source, with a high bacteria count, repeated sterilization and testing of the well may yield inconsistent results, sometimes passing, sometimes not.
What's wrong with just re-shocking the well and relying on the next OK water test result?
"Shocking" a well can temporarily make unacceptable water look fine. If no other corrective measures were taken than to "shock" the well, it is appropriate to follow the first acceptable water test with a second and perhaps even a third, spaced a week or more apart.
What's the best course of action for a buyer of a home that fails a well water test?
If in a real estate sale transaction the schedule does not permit these tests before closing, a buyer should consider requiring an escrow fund set aside during purchase of the property. This fund will guarantee acceptable water while giving the buyer a reasonable time, perhaps a month, to perform additional testing..
When to re-test a well that has been shocked with chlorine bleach or some other disinfectant
To be maximally effective at attempting to disinfect a well, the chlorine solution
needs to be in contact with the entire well casing and piping and water storage tank for 24 hours. Then the bleach-treated water is flushed from every fixture until there is no more bleach odor. A realtor/seller anxious to "pass" a bacteria test will try for an immediate re-test at that point.
WARNING: Wait. Don't re-test a well too soon.
We suggest a minimum of five days, preferably seven to ten days before re-testing a shocked well.
If there is a persistent source of bacterial contamination shocking the well won't fix anything.
The longer
you wait before re-testing a well for potability, the more time you're giving for the bacteria to reappear at a level sufficient to be picked up in the next water test.
If
circumstances force a too-quick follow-up bacteria test real to meet a estate closing date before adequate wait time has been allowed for re-testing
to be more credible, we recommend that the parties agree to escrow the cost of a proper water treatment system ($5000. to $10,000) and to allow
the new buyer 30 days to conduct follow-up testing. If at the end of that period the well is ok the escrow can be released.
Handling Failed Wells that Fail a Second Water Test Again: What to do if water fails a follow-up water test after well disinfection by Chlorination or Well Shocking
If the well water test still is not satisfactory, it is likely that there is a persistent source of contamination. Common sources of contamination include
loose or damaged cap on buried well casings, loose or damaged pitless adapter (where buried water line enters the well casing), a bad plumbing connection in
piping between the well and the building, spiders living in the well head and possibly insects they've dropped into the well, a dead animal in a well which
was not properly capped, and, less common, a cracked or damaged well casing. Damaged well casings can involve significant expense to repair or replace.
Since water systems can change, drinking water from private wells should be analyzed on a regular basis. The frequency of testing should be determined by the history of the water quality of the well.
Usually the property owner/seller is responsible for correcting unacceptable
water. Check with your attorney and your contract regarding this matter.
Often sellers have the well "shocked" using the sterilization treatment described above as a quick "fix" for a well that fails a bacteria test. This is a reasonable step to try IF the well has not already been shocked but otherwise, just trying this step over and over is probably wasting time and money, and it risks covering up a persistent contamination source that needs to be addressed.
In addition to sterilizing the well, an owner/seller or the new owner of a well that has failed a water test more than once in succession should:
Find the contamination source: have an experienced plumber or well service company look for, find, and correct a source of contamination such as a bad plumbing connection at the well (pitless adapter or well casing cap), bad plumbing between well and house (broken or leaky pipe joint), or bad or soiled plumbing components inside the house.
install water treatment/sterilization equipment such as a chlorinator/charcoal filter system or an ultra-violet light system. These systems work but require maintenance. Water treatment equipment are discussed in the next section.
Correcting the source of contamination is naturally preferred. But if a home is being sold, often schedule pressures do not permit longer investigation by a plumber to find a problem if it is not obvious. Therefore to provide safe potable (drinkable) water immediately, a water purification treatment system may be installed. If
that course of action is followed, we still recommend that the new owner/occupants attempt to find and correct the source rather than having to maintain equipment.
See WATER TREATMENT EQUIPMENT CHOICES for details of how we correct contaminated drinking water when simple well disinfection doesn't do the trick.
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Water Supply & Drain Piping, Wells, Pumps, Water Supply Equipment
Access Water Energy, PO Box 2061, Moorabbin, VIC 3189, Australia, Tel: 1300 797 758, email: sales@accesswater.com.au Moorabbin Office: Kingston Trade Centre, 100 Cochranes Rd, Moorabbin, VIC 3189
Australian supplier of: Greywater systems, Solar power to grid packages, Edwards solar systems, Vulcan compact solar systems, water & solar system pumps & controls, and a wide rage of above ground & under ground water storage tanks: concrete, steel, plastic, modular, and bladder storage tanks.
Cheating on water tests: Testing Water for Real Estate Transactions - make sure your water test is valid
Smart Tank, Installation Instructions, Flexcon Industries, 300 Pond St., Randolph MA 02368, www.flexconind.com, Tel: 800-527-0030 - web search 07/24/2010, original source: http://www.flexconind.com/pdf/st_install.pdf
Typical Shallow Well One Line Jet Pump Installation, Grove Electric, G&G Electric & Plumbing, 1900 NE 78th St., Suite 101, Vancouver WA 98665 www.grovelectric.com - web search -7/15/2010 original source: http://www.groverelectric.com/howto/38_Typical%20Jet%20Pump%20Installation.pdf
Typical Deep Well Two Line Jet Pump Installation, Grove Electric, G&G Electric & Plumbing, 1900 NE 78th St., Suite 101, Vancouver WA 98665 www.grovelectric.com - web search -7/15/2010 original source: http://www.groverelectric.com/howto/38_Typical%20Jet%20Pump%20Installation.pdf
Water Fact Sheet #3, Using Low-Yielding Wells, Penn State College of Agricultural Sciences, Cooperative Extension, School of Forest Resources, web search 07/24/2010, original source: http://pubs.cas.psu.edu/FreePubs/pdfs/XH0002.pdf
Water pressure tanks - how to diagnose the need for air, how to add air, stop water pump short cycling to avoid damage - water storage water pressure tank safety.
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.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop, and from the InspectAPedia bookstore. The 2010 edition of the Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
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
Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 "The evaluation of chemical germicides predates the golden age of microbiology..." -
This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals.
Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998.
"This superb book is the best of its kind available and one that will undoubtedly be useful, if not essential, to workers in a variety of industries. Thirty-one distinguished specialists deal comprehensively with the subject matter indicated by the title ... The book is produced with care, is very readable with useful selected references at the end of each chapter and an excellent index. It is an essential source book for everyone interested in this field. For pharmacy undergraduates, it will complement the excellent text on pharmaceutical microbiology by two of the present editors."
The Pharmaceutical Journal: "This is an excellent book. It deals comprehensively and authoritatively with its subject with contributions from 31 distinguished specialists. There is a great deal to interest all those involved in hospital infection ... This book is exceptionally well laid out. There are well chosen references for each chapter and an excellent index. It is highly recommended." The Journal of Hospital Infection.: "The editors and authors must be congratulated for this excellent treatise on nonantibiotic antimicrobial measures in hospitals and industry ... The publication is highly recommended to hospital and research personnel, especially to clinical microbiologists, infection-control and environmental-safety specialists, pharmacists, and dieticians."
New England Journal of Medicine: City Hospital, Birmingham, UK. Covers the many methods of the elimination or prevention of microbial growth. Provides an historical overview, descriptions of the types of antimicrobial agents, factors affecting efficacy, evaluation methods, and types of resistance. Features sterilization methods, and more. Previous edition: c1999. DNLM: Sterilization--methods.
U.S. Army Field Manual 21-10, Field Hygiene and Sanitation, 1988, web search 07/02/2010, original source: http://www.enlisted.info/field-manuals/fm-21-10-field-hygiene-and-sanitation.shtml The purpose of this manual is to assist individual soldiers, unit commanders, leaders and field sanitation teams in preventing disease and environmental injuries. The manual provides information on preventive medicine measures (PMM) to the individual soldier as well as essential information for the unit commander, unit leaders, and the unit field sanitation team on applying unit level PMM.
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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