Well Casing Holes

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Mr. Pickle

Mr. Pickle

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Location
Rogers MN
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Electrical
A municipal client pulled a well and found the bottom end of the steel casing has holes "like Swiss Cheese". They are asking what could have caused this and how to determine what the cause is? Has anyone dealt with a similar issue and thoughts on trouble shooting?
 
If it doesn't have holes in it how do they expect water that will be pumped to get into the casing?

Or are you describing something else?
 
Mr. Pickle said:
A municipal client pulled a well and found the bottom end of the steel casing has holes "like Swiss Cheese". They are asking what could have caused this and how to determine what the cause is? Has anyone dealt with a similar issue and thoughts on trouble shooting?
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GOOGLE JOHNSON WELL SCREEN
 
How old is the well? Before well screens, similar to Johnson well screens the well casing was slotted with a mechanical knife. I worked for a municipal water supply, we had one well that was drilled in the 30s that had a slotted, well casing, we didn’t use it much due to sand production.
 
Yes the casing is to have holes, but there are many other holes that are not supposed to be there. I am thinking it might have something to do with stray voltage?
 
Mr. Pickle said:
Yes the casing is to have holes, but there are many other holes that are not supposed to be there. I am thinking it might have something to do with stray voltage?
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Usually lightning strikes. I pulled a pump many years ago, and when I got it out, rolled it over, right where they had a label “Lightning Protected” there was about 10 holes blown through the motor case!
 
Can the well video be dropboxed to me? Would be happy to evaluate what is being seen. Have bee. A ,incensed driller since 1979. I specialize in large diameter, high capacity municipal and irrigation wells. I own downhole video inspection equipment. Last well video inspected was yesterday.

And yes I have seen corroded casing with holes in casing that was less than 25 years old. Can be effected by water chemistry, grout or lack of grout on exterior of casing, stray voltage, vibration of pump and column pipe against casing or screen, and other causes.
 
Here’s some rotted out casing we speared and removed from an irrigation well. We replaced this liner with new casing.
 

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The one thing that must be avoided completely is any connection through the well casing to any acquifers or ground water pools other than the one which is intended to feed the well. Such connections can result in contamination from a contaminated upper acquifer or ground water to the "pure" acquifer below them.
In the Silicon Valley area of California there have been extensive problems with abandoned agricultural wells carrying contaminants from the early semiconductor industry and leaking service station tanks down to the domestic water acquifers. To avoid problems from the eventual rotting out of well casings currrent regulations require abandoned wells to be filled (typically with concrete or grout, I think.)
P.S. OK, I see now: make that bentonite clay, which is nicely impervious to water and fills everything well [sic].
 
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I'm in the process of drilling a new well for a farm worker housing project for an apple orchard. The existing well was too close to the road to be used for a group A water system. We are backfilling the well with bentonite chips and jacking the well casing out of the ground. The new well was completed Monday. Set the test pump today. Will flow test the well and take water samples. For a single family domestic well, we test for coliform bacteria and nitrates. In some areas we also test for arsenic. For group A & B water systems, the testing is much more extensive. We then also test for herbicides and pesticides, inorganic chemicals, organic chemicals, and volatile organic chemicals. This regimen of water tests will cost $2-3,000.
 
Dzboyce said:
I'm in the process of drilling a new well for a farm worker housing project for an apple orchard. The existing well was too close to the road to be used for a group A water system. We are backfilling the well with bentonite chips and jacking the well casing out of the ground. The new well was completed Monday. Set the test pump today. Will flow test the well and take water samples. For a single family domestic well, we test for coliform bacteria and nitrates. In some areas we also test for arsenic. For group A & B water systems, the testing is much more extensive. We then also test for herbicides and pesticides, inorganic chemicals, organic chemicals, and volatile organic chemicals. This regimen of water tests will cost $2-3,000.
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Have you tested for Radon? City of Hoschton Ga. Had two wells, one old one about three blocks down from the water tower, the second new one was about 50’ from the tower. They could not use the new one because of a high Radon count.
 
tom baker said:
Corrosion is caused by DC current, not AC
Where would the stray voltage come from?
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Dissimilar metals in brackish water cause galvanic corrosion.

How Do Sacrificial Anodes Work?​

Any time you have two different metals that are physically or electrically connected and immersed in seawater, they become a battery. Some amount of current flows between the two metals. The electrons that make up that current are supplied by one of the metals giving up bits of itself — in the form of metal ions — to the seawater. This is called galvanic corrosion and, left unchecked, it quickly destroys underwater metals..
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I have been involved in several similar cases where submersible pumps were destroyed as you described.
The anode-cathode system used to protect pipelines has been the cause every time.
The pipeline company will tell you no, until you show presence of DC voltage and currents.
They will talk about the neutral to earth voltage caused by the utility. The utility does not make DC power in most places.
Drive around, and when you start seeing rectifiers near pipeline markers, testing can be done at those locations to check the output of the rectifiers.
 
Water chemistry, in particular low pH can cause corrosion. My water systems water from a surface supply (dam) has a PH of 8.0. The water is treated to raise the pH to 8.5 and reduce the corrosion potential.
 
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