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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
How to measure well depth: this article series describes how we measure the depth of a water well. We caution that the amount of water available and the water delivery rate ability of various types of drinking water sources like wells, cisterns, dug wells, drilled wells, and even artesian wells is not answered just by measuring the depth of the well itself, but still we often need to know this number in order to know how to shock the well or how to prepare pipes, controls, and well pump choices or settings
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The sketch at page top, courtesy of Carson Dunlop, outlines what happens during a well drawdown or well flow test procedure. Details are below. 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.
In a companion article, How to Test Well Water Quantity, we describe both valid and questionable ways people measure well yield, and we offer some simple steps any home owner or home buyer can take to check the adequacy of water pressure and water quantity at a building.
First you have to find the well. Second you need to know what kind of well is installed: driven point, drilled, or hand dug well, for example.
Two Key Questions to Ask About the Water Well
If you are purchasing a property served by a private well of any sort, here are the critical questions to ask about the well itself:
Watch out: Measurements like the well depth, well flow rate, well recovery rate are all useful, but taken by themselves some of these numbers can give a false reading about the basic question of how much water is in the well? What we really need to know is the total quantity of water that can be drawn from the well and the quality of that water: is it potable, hard (mineral laden), smelly, dirty, requiring treatment for any aesthetic or health-concern contaminant? See How Much Water is In the Well? and see How to Test Well Water Quantity.
How to Find the Depth of a Well - String and Weight Method
The Water Ace Pump Company offers this nice, simple well depth measurement procedure that works for drilled wells or hand dug wells. We have added some details.
For relatively shallow wells, 30' or less, we sometimes use a tape measure directly, but a weight on a string assures that the line used to make a measurement is absolutely straight, so more accurate.
Watch out: be careful putting anything into your well, that you don't send down a weight that gets hooked on pipes or valves in the well bottom. Use a small fishing weight or a rounded object and tie it carefully.
Watch out: this procedure is important for matching the well pump capacity to the physical depth of the well opening in the ground. But it does not tell us much about how much water is actually in the well. Except for artesian wells, the top of the water level in the well will virtually always be some depth lower than the top of the ground surface.
Matching Well Pump Capacity to Well Depth
Water Ace continues:
FYI the five foot deduction from the physical well depth used to estimate pump capacitu is assuming that the water pick-up end of your in-well piping will be held about five feet off of the physical bottom of the well. That's because placing the water pick-up too close to the very bottom of the well risks picking up silt and debris, clogging the foot valve, piping, and water pump.
Additional reading about water wells:
Frequently Asked Questions (FAQs)
Question: how do I measure the depth of the steel casing part of my well?
The current well casing is 6” steel and rusting, evidenced in the drinking water How do I determined the length of this casing? - J.D. 6/8/2013
Reply: string and magnet method; well camera method
My first preference in finding out details about a drilled well using a steel casing is to look in the building for notes about the well location, depth, and specifications; often the driller or plumber provides that data in writing and it may also be written on a wall or ceiling joist in a basement or crawl area where the well pipe enters the building, or at the water tank and well pump. I've also had success calling local well drillers to find out who drilled the well as usually the company keeps well drilling record.
But if you are left with no information and need to know just the depth of the steel well casing (as opposed to the total well depth) try this procedure, working carefully to avoid dropping anything into the well or hanging up your cord and weight-magnet.
Watch out to avoid hanging the magnet up on the well pump, pipe connections, wiring. I like a round or cone-shaped magnet that is less likely to get caught up, and one that is just an inch or so in diameter;
Watch out: Don't drop stuff on the well.
An alternative is to hire a well service company who offer an inspection camera service. Such cameras are lowered into the well to inspect for casing cracks, rust holes, damage;
Question & answers on the procedure to make the basic measurements of a water well: diameter, depth, water level, static head. .
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.