Water Well Question

[MarkSLSmith]

Folks,

I haven't been able to find a clear answer to this question.  

Can I turn off the well pump for an extended period of time, say 2 months?  If yes, would it make any difference to drain the pressure tank?  Draining the pressure tank would depressurize the whole system.  

Thanks,
Mark

[fredhargis]

I don't know what the correct answer is, but I always turned ours off if it would be unused for that length of time (I think that only happened twice.)  I drained the pressure tank each time. This was as much to protect the house as the water system...I didn't want some kind of leak occur and flood the house.

[blackhat]

Yes, you can turn it off that long. Yes, depressurise the system. 

Care to share some reasons you’ve heard not to?

[MarkSLSmith]

Yes, you can turn it off that long. Yes, depressurise the system. 

Care to share some reasons you’ve heard not to?

The well depth is 340' and the casing depth is 37'.  Will removing the pressure have any negative effect on the portion below the casing?  Is it possible for the walls to erode or collapse if the water doesn't have 30 - 50 psi of pressure on it?

I'm completely new to well ownership, so if these are stupid concerns please be tactful.

Thanks,
Mark

[Snipe Hunter]

The well depth is 340' and the casing depth is 37'.  Will removing the pressure have any negative effect on the portion below the casing?  Is it possible for the walls to erode or collapse if the water doesn't have 30 - 50 psi of pressure on it?

I'm completely new to well ownership, so if these are stupid concerns please be tactful.

Thanks,
Mark

The pressure isn't in your well itself. It's in the well pipe, supply pipe and your pressure tank. So the pressure is between your plumbing fixtures and the last check valve. That last check valve is usually within 20ft of the well pump. Maybe even attached directly too it. The well head is vented so the "air" pressure inside the well stays static even if the water level goes up or down or if you have the water running or off.

[Tim in Indiana]

I have turned mine off for up to 6 months at the cabin. No problems.

As Neil explained the pressure is within the small 3/4" to 1" line, between your pressure tank and the check valve. Not the 4"-6" drilled hole. You most likely have a submersible pump with a check valve in the pump so water is held in the pipe all the time. Even if you were to lose the pressure in the pressure tank there is water sitting in the pump and line.

It should prime itself and pump up when you restart it.

[blackhat]

A couple points. A well is a hole in the ground. Casing is the pipe sleeve that keeps it from collapsing back in on itself. A 340 ft well should have 320 plus ft of casing with a section of screen on the bottom to make 340 feet. Screen size depends on flow and was settled when the well was drilled. No changing screen or casing now. 

Perhaps the 37 foot number is the drop pipe to the pump?  A bit unusual for a well that deep and the pump that shallow but certainly not impossible. 

The pump has a check valve at the top of itself where the drop pipe is connected. It prevents the water from the house draining back down into the well. Even if that leaks a bit, the pipe stays full to normal water table. The drop pipe can’t be empty below water level, and even if it was, it would need several hundred feet of head pressure to collapse it. Think of a straw in a glass of water. 

If the pump isn’t running, nothing is moving so no concerns about damage there. If the water is really nasty, you may need to manually cycle any water treatment equipment you have after turning things back on. Unplug that equipment while the well is turned off. 

Any other questions or concerns, fire away.

[EightFingers]

When we lived in Hawaii, I shut the well down anytime we were gone more than a week.

Never had a problem.

[jlanciani]

A couple points. A well is a hole in the ground. Casing is the pipe sleeve that keeps it from collapsing back in on itself. A 340 ft well should have 320 plus ft of casing with a section of screen on the bottom to make 340 feet. Screen size depends on flow and was settled when the well was drilled. No changing screen or casing now. 

Bedrock wells are typically only cased from the surface to the bedrock. My 500' hole in the earth only has 40' of casing. No screen either, just a pump at the bottom of a 480' long riser pipe.

[Stwood_]

Bedrock wells are typically only cased from the surface to the bedrock. My 500' hole in the earth only has 40' of casing. No screen either, just a pump at the bottom of a 480' long riser pipe.

Same here. 200' well with 20' of steel casing.
Check valve screwed directly on the bottom of the pump. No screen.
Sure don't need a screen plugging up that far down.