Drilled Steel Casing Modern Drinking Water Wells, Types & Repairs InspectAPedia® -
Drilled Steel Casing Modern Drinking Water Wells, Types & Repairs
Types of wells and water supply systems and what to watch out for with each
Well pump & water tank diagnosis & repair procedures
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This article describes Drilled Steel Casing Modern Drinking Water Wells, Types & Repairs. We provide advice about what to do when things go wrong. Readers of this document should also see Water Tank Types and before assuming that a water problem is due to the well itself, see Water pump and pressure tank repair diagnosis & cost an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.
The page top photo is of a modern well casing, in good condition, extended properly above ground.
The small-diameter pipe parallel to the six-inch steel well casing is an electrical conduit - so we
know that for this particular water supply system a submersible water pump is used and it is
installed in the well itself.
The electrical conduit carries electrical power to the water pump
down in the well.
The blue and white plastic rope in the page top photo was probably used to raise and lower
the well piping and pump from within the casing.
In Carson Dunlop's sketch at left we show the typical construction of a drilled water well in cross section.
You can see that the typical well casing diameter is 6" (4" in some areas), that the well depth can be considerable (50 50 ft. to 900 ft. or more), and that the steel well casing does not extend down into the bedrock.
As we show in In Carson Dunlop's sketch at left, there are several types of well casings and more than one type of well casing sealant.
Drilled well casing types: Drilled well casings can also be constructed of plastic pipe, brass pipe, copper pipe, or fiberglass pipe.
Drilled well casing sealant with concrete or gravel and slurry: A concrete slurry or gravel and mud mixed grout is poured around the exterior of the well casing after it has been pushed into the drilled well opening.
This grout is necessary to prevent surface water from leaking into and contaminating the well water. The water that enters this well comes from cracks or fissures in water bearing rock shown at the bottom of the sketch.
Not shown in this sketch are the well details such as submersible well pump, well piping, pitless adapter, and piping between the well and the building it serves. We discuss the pitless adapter and these other parts below.
The photo shown here is of an older drilled-well casing which has been placed with its casing
cap at ground level - increasing the risk of well contamination from surface runoff.
All we can see is the well cap.
The water pipe leaving this well to carry water to the building will be buried below ground,
and in freezing climates, below the frost line.
A special fitting, the "pitless adapter" is
used to seal the passage cut into the round well casing to permit the water piping
to pass through the casing and out to the building it serves. One of our readers was having trouble pulling the pump and piping up out of their well - the pump jammed in the casing near the top of the well. We wondered if the pump was unable to pass by the pitless adapter since this fitting intrudes into the well casing. Stay tuned.
Most modern drilled wells for residential properties use a 6" steel casing which is
inserted into the drilled hole prepared by the well driller and then sealed at top and
bottom against contamination by surface water or surface runoff.
The best way to locate a well and well casing to avoid surface water contamination is shown
in this illustration.
You can figure on about 1.5 gallons per foot of depth of a well using a 6" well casing - but remember you have to find the height of water column available to the pump. Except in artesian walls the water column does not extend from the well bottom to the top of the ground.
Key to our sketch of the parts and features a drilled water well:
a = air - the distance from the ground surface to the top of the water when the well is at rest and is fully "recovered" from recent use
c = clearance distance between the bottom of the well pump (or foot valve) and the very bottom of the drilled well. this distance is required to avoid having the pump pick up mud and debris from the well bottom.
h = static head: the volume of water available to the well pump when the well is at rest and is fully recovered.
Bored Water Wells
A bored water well is a lot like a 'drilled well' and the use of this term is confusing to some.
The differences between a bored well and a drilled well are these:
Unlike a drilled well described above, the bored well is prepared using different equipment which is not capable of boring to as great a depth.
As Carson Dunlop's sketch shows, the bored well is often lined with interlocking sections of concrete piping rather than a continuous steel casing.
A bored well is likely to be found in areas of high water table, and where the water supply is obtained from water bearing soil or sand rather than bedrock.
The usual depth of a bored well is 50' to 100' - not as deep as a drilled water well.
Definition of & Formula for Determining Water Well Recovery Rate
We provide an introduction to well recovery rate just below. Details of "how much water is in the well" are discussed at How Much Water is In the Well?
The well recovery rate is the rate at which water flows into the well opening from surrounding rock (or soil or other water source). The well recovery rate is a complex number comprised of the water flow rate and water flow duration from various rock fissures and openings into the well casing or well opening.
Because water flowing into the well from a particular rock crack or fissure often flows at a varying rate, typically falling to a lower rate or even stopping after time, the total well recovery rate involves a summation equation adding up the individual rock fissure flow rates and considering the length of time that each flow rate can be expected to occur.
The length of time that each flow rate at each fissure may occur varies from just a few minutes to more than 24-hours. Flows that continue at a given rate for 24-hours or more are considered "indefinite" for practical purposes because the usage level (taking water out) at a residential property is typically measured on a 24-hour use cycle.
R = total recovery rate
r = individual rock fissure well flow rate for individual flow rate times (for example rock fissure #1 may involve one or more flow rates depending on how its flow rate varies. We add all of these r's for each rock fissure together to get the total flow from that fissure over 24-hours)
n = the total number of rock fissures feeding the well at all depths of the well opening
R0 = SUM [r1 - rn]
To include the variation in flow rate over time at each rock fissure that feeds a water well, we write an integral equation something like this:
R = [INTEGRAL 0 to X] SUM [r1 - rn] where the interval 0-X represent the varying flow rates over time.
Definition of Total Water Available from a Water Well over a Given Time Period
The total volume of water available from a water well is the sum of the static head plus the recovery rate for the time period, typically 24-hours.
Volume of Water over 24-hours = Static Head (h) + Recovery Rate (R)
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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 [ copy on file as /water/Smart_Tank_Flexcon.pdf ] - , 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 [ copy on file as /water/Jet_Pump_Grove_Elect_Jet_Pumps_1.pdf ] - , 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 [ copy on file as /water/Jet_Pump_Grove_Elect.pdf ] - , 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 [ copy on file as /water/Low_Yield_Wells_Penn_State.pdf ] - , 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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