Well pump sizing

[IXLR8]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

 

[MAX-24-Dean]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

A "horizontal pump" (centrifugal pump) only has a lift capacity of about 25 feet. If your well is only 100 feet deep you would only need a 1/2 HP (vertical pump) motor unless you irrigate a garden out of this well and want more gpm.

 

[tradosaurus]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

I replaced my 1 HP convertible jet pump with a 1/2 hp 10 gpm submersible pump. Granted mine is a 42 ft shallow well and pipes water about the same distance (100 ft) to the house.

Quieter operation and used less power. Couldn't stand how loud the jet pump was since it was located above the well and the well is located in the shed where my tools are located.

 

[ning]

Definitely need to know how deep the pump is in the well, as well as whether or not the house is higher than the well. At most you'll need a 3/4hp, likely 1/2hp. This depends on desired flow rate and total head, which is the height difference from the pump to the high point in the house (multistory houses need slightly higher pressure).

My well is 180' deep, pump is at 165', bottom floor of house is 15' above the well, two-story house, about 150' pipe between the well house and the house with some 45* bends... all these things contribute to "needs more pump". 3/4hp gives me 10gpm, which is more than the well can handle for very long (but is fine for relatively short uses, like filling a tub) (well the total depth of the well doesn't matter for this but for other things).

 

[Sportsman762]

The depth of a well is irrelevant, I worked on a 300' well that had a pump hung at 27', it was an odd area where the water was deep, but the water level was high. How deep is the water table, how much draw down does the well have, what is the desired flow rate (or the production capacity of the well), and how far must it pump. A low production well, will draw down bad when pumped so the pump has to be hung deeper.
I am guessing a "vertical pump" is located in the well on the bottom of the drop pipe? If so this is considered a submersible pump as it is submerged. I am guessing a "horizontal pump" would be a jet pump like tradosaurus's photo shows. If your going from a jet pump to a submersible pump, you will need more pipe as you have two pipes going down the well, and you will need a venturi / foot valve on the bottom. Jet pumps pump some water down the well, through the venturi that creates suction, bringing up more water than you pumped down. A damn inefficient way to move water.

If the pump is hung at 100', you are going to need a submersible pump as jet pumps are good for shallow wells.

I would not go with a jet pump over a submersible. They are much less efficient, and it would be a pain to switch from a submersible to a jet, your cost savings would also be eaten up when you factor in the additional pipe, venturi, and pump. I would just switch the pump out, as long as it has worked well in the past.

 

[gary49]

I’m not sure what you mean by vertical pump that is in a pump house. That implies that the pump is above the ground and as others have noted, a shallow well jet pump is the type of pump one typically sees above ground. I believe I’ve seen illustrations of a jet pump that uses the well pipe to carry water up, maybe the well is one of those? If so, I think the casing of the well would be 2” nominal pipe. There are deep well jet pumps, and they use two pipes down the well, with an ejector assembly at the bottom above a foot valve (check valve with a screen). I think you will want a submersible pump, on a 100’ well it would typically be 85-90’ down. Jet pump is less efficient and more troublesome than a submersible. Is your well too small for a submersible pump? Hopefully it is a 6” well, but it could be smaller which might explain why it has what sounds like some form of jet pump. 1/2 hp should be fine on a 100’ well assuming you don’t have a need for water flow beyond 10 gpm and assuming you can install a submersible pump.

 

[IXLR8]

The pump is sitting on top of a piece of 1-1/4" PVC about 12" above the ground. It is a level run to the house, maybe up 2 ft. There is that single pipe going down into the well that the pump sits on and one pipe heading to the house.

 

[ning]

The pump is sitting on top of a piece of 1-1/4" PVC about 12" above the ground. It is a level run to the house, maybe up 2 ft. There is that single pipe going down into the well that the pump sits on and one pipe heading to the house.

Can you show a pic of the pump?

 

[caver]

I was doing homework for a well I will have drilled possibly this summer on my home build site. This young guy gives lots of advice and seems pretty solid. He seems to focus on the service call and fracking side but the family? business also drills wells. https://www.youtube.com/@h2omechanic

 

[3Ts]

I have seen vertical pumps that sit over the well, BUT they have all been agricultural wells, meaning they're about a foot in diameter and pump hundreds of gallons per minute. So, I'm confused as to what you actually have. All the above ground pumps I'm aware of can not lift water more than 25 feet.

The distance in elevation from the water surface in the well to the house will determine the pump specifications. The flow rate and size of pipe will add a little to it.