Looking for some advice on a new well pump install.
The current water depth (using a fishing bobber) is about 40' down from the surface. The well itself is somewhere between 340-360ft deep. There's 6" diameter casing for the first 60' until it hits bedrock. Then there's no casing, just rock the rest of the way.
This is new construction, so I don't have any way to test the refill rate, although I think the driller said it was at least 5GPM refill.
If a 6" well is 1.5 Gallons Per Foot (got that figure online somewhere), then water at 40' and a 340' depth would mean 300' x 1.5 = 450 gallons in the shaft. At 10GPM, that would run continuously for 45 minutes without any refill factor, if the pump were near the bottom.
For two people, I can't imagine using that much water at a time. A washing machine and a shower (there's only one shower and one bathroom right now, but I might add (at some point) another toilet+sink (no shower or tub) so guests don't have to use ours.
I also plan to do some gardening and will need water to fill a pond (if rain is insufficient) and for irrigation. But that seems more like low-flow over a longer time. For example, a hose bib left on for a few hours.
I'm thinking I should get the biggest pressure tank I can, maybe something in the 80 gallon range, to minimize pump cycles. An 80 gallon tank could supply a 30 minute shower with a 2.5 GPM head with only one pump start. A 10 GPM pump would then run for 8 minutes to refill the tank before shutting off. (I'm sure that math isn't quite right... because it's based on pressure, not on the tank being empty, but I think you get the jist of it).
An 8 minute run of a 10GPM pump would draw down ~55 feet of depth, reducing the water level to about 95' from the surface.
Except, with 5GPM back-filling, 40 gallons would come back in during that 8 minute draw, replacing 26 feet. So it would be 70' to water level after the completed pump cycle.
So: How stupid would it be to set the pump at 150ft? 200ft? And not 340ft?
And: If the refresh rate is 5GPM, is there a reason to do a 10GPM pump?
I also want to do a hand pump because I'm in a rural area where the power company takes it's time restoring after a storm. ie. seven days. So I was looking at the Bison, because it works inline and can refill your pressure tank. So you could hand pump the tank full then take a shower.
Friction loss: Is this calculated horizontally from the well head to the pressure tank, if the pressure tank is right next to the well head? Or should the line to the house (after the pressure tank) be factored in?
I feel like I'm going in circles with the horse power, depth, and GPM ratings. Not sure what size to use.
It looks like a Franklin Series V "7GPM" 1HP can do 9GPH @ 50PSI @ 100ft water depth. If I'm reading the table correctly. And I assume that means if it's 100' to water, no matter how deep the pump is.
But I'm not sure what depth to set it at, vs HP, vs GPM rating. Any recommendations?
The current water depth (using a fishing bobber) is about 40' down from the surface. The well itself is somewhere between 340-360ft deep. There's 6" diameter casing for the first 60' until it hits bedrock. Then there's no casing, just rock the rest of the way.
This is new construction, so I don't have any way to test the refill rate, although I think the driller said it was at least 5GPM refill.
If a 6" well is 1.5 Gallons Per Foot (got that figure online somewhere), then water at 40' and a 340' depth would mean 300' x 1.5 = 450 gallons in the shaft. At 10GPM, that would run continuously for 45 minutes without any refill factor, if the pump were near the bottom.
For two people, I can't imagine using that much water at a time. A washing machine and a shower (there's only one shower and one bathroom right now, but I might add (at some point) another toilet+sink (no shower or tub) so guests don't have to use ours.
I also plan to do some gardening and will need water to fill a pond (if rain is insufficient) and for irrigation. But that seems more like low-flow over a longer time. For example, a hose bib left on for a few hours.
I'm thinking I should get the biggest pressure tank I can, maybe something in the 80 gallon range, to minimize pump cycles. An 80 gallon tank could supply a 30 minute shower with a 2.5 GPM head with only one pump start. A 10 GPM pump would then run for 8 minutes to refill the tank before shutting off. (I'm sure that math isn't quite right... because it's based on pressure, not on the tank being empty, but I think you get the jist of it).
An 8 minute run of a 10GPM pump would draw down ~55 feet of depth, reducing the water level to about 95' from the surface.
Except, with 5GPM back-filling, 40 gallons would come back in during that 8 minute draw, replacing 26 feet. So it would be 70' to water level after the completed pump cycle.
So: How stupid would it be to set the pump at 150ft? 200ft? And not 340ft?
And: If the refresh rate is 5GPM, is there a reason to do a 10GPM pump?
I also want to do a hand pump because I'm in a rural area where the power company takes it's time restoring after a storm. ie. seven days. So I was looking at the Bison, because it works inline and can refill your pressure tank. So you could hand pump the tank full then take a shower.
Friction loss: Is this calculated horizontally from the well head to the pressure tank, if the pressure tank is right next to the well head? Or should the line to the house (after the pressure tank) be factored in?
I feel like I'm going in circles with the horse power, depth, and GPM ratings. Not sure what size to use.
It looks like a Franklin Series V "7GPM" 1HP can do 9GPH @ 50PSI @ 100ft water depth. If I'm reading the table correctly. And I assume that means if it's 100' to water, no matter how deep the pump is.
But I'm not sure what depth to set it at, vs HP, vs GPM rating. Any recommendations?