Coliform in well

[Kerri L. Grabowski]

I have tested my water over the years and have had no problems.
This time I came back positive for Coliform.
I shocked my well twice, which reduced the count but did not totally remove it.
I spoke a neighbor in the area, and he said he had that problem a few years back due to a cracked casing in the well.
My well is very deep, approx. 330 ft.
I installed a submersible pump about 13 years ago, and it is about 60ft. down, likely the length of the casing.
They say to check to the casing and I certainly can’t do a visual.
The well itself would be quite old, probably at least 30 to 40 years anyways.
Do you know if there is some kind of pressure test you can perform or can it be scoped?

Any feedback would be helpful.

Kerri

[Stephen W. Stanczyk]

Kerri, What did you use to shock it and how much? You know the depth of the well is 330', but how deep is the water level from the surface?

For wells between 300-400 feet of water, if you have a 8" casing at that depth, it would take 2.5 gallons of bleach. It should sit for 24 hours. Some say 12 hours but in my experience, the 24 hours makes a difference.

It is not just the well that must be treated. The expansion tank, water heater and all the lines must be treated as well.

[Nick Gromicko]

How would a cracked casing cause a persistent Coliform problem? Are you thinking the crack is close to the surface and you are getting surface water into the well?

[Joe Farsetta]

This can very well be the cause of contamination. A Jaswell seal may be the answer.

[Kerri L. Grabowski]

Pardon my ignorance, but what is a jaswell seal?

[Kerri L. Grabowski]

Maybe...