Calculating Submersible Pump Size

[RobertV]

Hi all,

First, thanks for this website. So much great info here.

I have a new well to supply water to a tiny cabin and I need to calculate the submersible well pump needed. Any help will be really appreciated. The well is in New Hampshire so it will be buried 4' underground from the well head to the cabin

Details:

Well is 242' overall. I want to set the pump at 227'.

There is roughly 300-310 gallons of water in the well at any given time (about 18'-20' below top of steel well sleeve). The well recharge is 1.5 gallons per minute.

From the well to the cabin, it is 83'. I am using 200psi, 1" water line and 10 gauge wire to serve the pump.

Where the waterline reaches the cabin, the line sweeps up to the pressure tank roughly 6.5' from the bottom of the waterline trench. The pressure tank feeds 1/2" pex water line that runs overhead thru ceiling joists (another 6 feet up from where 1" line connects to pressure tank) to the following: one kitchen sink faucet, one bath sink faucet, one bathtub faucet, one toilet, one washer/dryer feed. That's it.

I am shooting for 7-10gpm.

Can anyone out there help me size the pump needed for this system? Is there more info that you need from me to do this?

Thanks again...reading through this forum is a hell of a lot of fun.

 

[Reach4]

Maybe 1/2 HP 5 GPM pump with a 7 GPM Doll valve and a 32 gallon or bigger pressure tank, or 3/4 HP 7 GPM with maybe a 10 GPM Dole valve preventing upthrust. 44 gallon or bigger pressure tank.

 

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[Valveman]

If the water pulls down to 220' a 3/4HP won't deliver 8 GPM at 50 PSI. I would go with a 10 GPM, 1HP. Then with a PK1A kit using a Cycle Stop Valve you can still use that pump down to 1 GPM when needed.

 

[Reach4]

If the pressure drops as your water drops below 180, is that all bad?

I would go with a 10 GPM, 1HP. Then with a PK1A kit using a Cycle Stop Valve you can still use that pump down to 1 GPM when needed.

Dole valve?

 

[Valveman]

If the pressure drops as your water drops below 180, is that all bad?


Dole valve?

No. No Dole valve. The well has 300 gallons stored. As long as you don't use more than 300 gallons at any given time you should be ok. But if you want to run irrigation or something long term, you will need to time it carefully, or use a cistern storage tank and a booster pump.

 

[RobertV]

Thanks a ton, gents. This is a huge help.