I have an irrigation well, 4" caseing, submersible pump, about 25 gallon
pressure tank. Following a hurricane I did not use the well for several
months. Then, the next spring, when I did try to use it, I could only get
the pressure up to about 20-25 psi. When I turn the pump off, the pressure
quickly drops to zero.
No trees fell near the line except very close to the well casing. I have
dug down to the pitless adapter and there is no leak there. I do not
believe the water is leaking at inside the casing and running back down
into the well because I do not hear it and because there is a diaphram on
the drop pipe that fits tightly against the inside of the casing (to create
a vacuum below it when the pump is running and increase water flow ) which
would cause the casing to fill up. That is not happening.
Since I already has a spare pump, I pulled up the old one in case its check
valve was bad, and replaced it. The drop pipe looked fine. Still the same
problems (low pressure, pressure drops to zero when pump is off).
I do not think that the well is just no longer able to produce the
necessary flow because that would not explain the drop in pressure when it
is switched off.
I can think of no reason the underground pipe would be broken and it would
be a huge job to dig along its length and check for a leak.
What is/are the most likely cause(s) of this problem other than a leak in
the underground pipe.
The pipe is 18"-24" below ground (below our freeze line). Is there any to
locate a large leak other than digging along its length?
MANT THANKS for any help.