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WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONTAMINANT LEVELS
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
This article describes drilled wells that use a steel well casing, modern drinking water wells. We discuss well problem diagnosis, testing, & repair procedures - advice about what to do when things go wrong with the well such as loss of water pressure, not enough water volume, contaminated wells, wells that have smelly water, wells that just run out of water or have a low recovery rate. We describe the parts of a water well and its piping and controls including the pitless adapter. We explain how a well water recovery rate is measured or calculated. We explain the role of static head of water in a well and how to measure the static head.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Here we describe modern steel-casing drilled water wells, including how the well is constructed, sealed against contaminants, and how the well flow rate or water recovery rate is evaluated.
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.
Key to our sketch of the parts and features a drilled water well shown just above
d = well depth as drilled. More about measuring the depth of a well is at DEPTH of a WELL, HOW TO MEASURE
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.
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.
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)
Details of "how much water is in the well" are discussed at How Much Water is In the Well?
Frequently Asked Questions (FAQs)
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Technical Reviewers & References
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