Advice: Simple one for you guys! Well to house run

[Aja DiGirolamo]

Just a couple of simple questions, since I'm running under a slab, I do not want to get the incorrect size on anything.

Well: 380ft with 12GPM
House: 50Ft from well with kitchen, full bath with plans for half bath later.
Cottage: 300ft+ from the house with a full bath.

- I was thinking of going with 1-1/4" blue ploy pipe for both runs, sound good?
- Any suggestions for well pump sizing?
- Pitless adapter, how hard is it to drill out the casing as a DIY?

I have a million questions but this gets me on the right path if you guys have the time. THANKS!

 

[Valveman]

Just because your well is 380' doesn't mean the pump needs to lift from that depth. The pump is only lifting from the actual water level, no matter how deep the pump is set. It is very common for a 380' well to have a static level of say 50', and a draw down of maybe 200'. So the pump only needs to be set at 220', and is only lifting from 200' after the well draws down over time.

From 380' to get 12 GPM at 50 PSI at the house you would need a 2HP, 10 GPM series pump. But if the water level never draws down below 200', you would only need a 1.5HP pumps.

Yes 1 1/4" poly would be fine for those runs. Drilling a hole in PVC casing is easy, but not so much in steel casing.

 

[Sponsor]

 

[Reach4]

For both the cabin and house supplied from the same well, I would go with a 10 gpm pump. That 12 gpm number was probably what they were saying the well itself could produce. Your cabin and house does not need that. Where will you tee the house and cabin pipes?

While running pipe, consider adding a yard hydrant.


If you are ever going to try to power this from a generator, you don't want to oversize your pump, and you might select a pump with a generator in mind.

One inch SIDR should be enough, but 1.25 would have lower drop. One inch SIDR is bigger than 1 inch. At actual 1 inch, 300 ft is around 11 psi drop.

Do not pull the pipe tight, but rather snake it some to allow for thermal contraction.

What is the casing size? That has a lot to do with the choice of pitless, and maybe the pump.

What is the casing material? If you have 4 inch steel, you would be better to use a 3 inch pump.

 

[Aja DiGirolamo]

Thanks guys!

I believe its 4in steel casing, I will measure it out tomorrow morning. Talked with the well drillers and he said 3/4HP pump, at 240ft with 1" line and 12/2 UF cable run.

I would run the outbuilding after the pressure tank in the main house, to keep it simple and I would be able to bleed out the cottage in the winter if I ever needed to.

Is the blue Ploy CTS tubing at HD worth it if im going under the slab?

 

[Reach4]

I believe its 4in steel casing, I will measure it out tomorrow morning.

If you run a "4 inch" pump in 4 inch steel, at least make sure it is a trimline/slimline/streamline size (about 3.75 dia). The worry is that corrosion could make a more regular size (3.9 dia) pump get stuck. Even better, and what I think I may go with if the Trimline pump (first installed 2002) in my 4 inch steel steel casing ever fails, is a 3 inch SQ pump. I am still not totally comfortable with the idea of the high RPM, but those seem to be reliable.

I have a Merril SMCK pitless adapter on my 4 inch casing, which does not block the pump. The alternative is to get an adaper made and welded to expand the pitless area to 5 inch.

 

[Mliu]

What is your reason for going under the slab?

 

[Aja DiGirolamo]

What is your reason for going under the slab?

How else would i get into the interior of the house?

 

[Aja DiGirolamo]

The casing is 6"

 

[Reach4]

The casing is 6"

Good. So you can use a trapezoidal pitless adapter, and any 4 inch pump.

Take notes on what pitless you use and what pump you use. Pass that helpful info on to the buyer after closing, if you sell. Knowing what pitless adapter that is would tell you what the o-ring is.

They use a bi-metal hole saw to make the hole. Clearly you would want one durable to go through the steel.

I presume your casing extends above ground.

Put a flow inducer sleeve on your pump to make the motor last longer due to better cooling. It also can have some other advantages. It's cheap and usually homemade.

 

[Mliu]

How else would i get into the interior of the house?

Just checking. Some people do really goofy things.

If you're in a freezing climate, the pipe must be buried below the frost line. Make sure the poly pipe is continuous under the slab (no joints or connections). Sand the trench. The poly MUST be wrapped where it passes through the slab.