What size water line needed?

[Raindem]

Good afternoon. I'm running a 130' water line from my house to the barn. I plan to tap into one of the outside spigots (which is fed by 1/2" copper line). We're on well water and our pressure at the spigot is around 40-50 psi.

What size PVC line should I be running? Due to the distance I'm guessing it needs to be bigger than the 1/2" feed line. If it makes any difference it's a slight downgrade from the house to the barn.

Thanks for your input.

Curt

 

[phishfood]

I would run 1" for that kind of distance.

The 1/2" spigot will restrict how much water will be availabe at the barn. But if you don't need a large volume of water, you should be OK.

 

[Caduceus]

To add to phish's response, if you wanted more volume than a 1/2" line can provide then you would need to tap into a water supply equal to (or larger than) the size of the pipe you are running. Installing a 1" line onto a 1/2" line will still only give you the volume of the 1/2" piping.

 

[LiQuId]

you could put in a cistern if you required additional volume.

 

[Raindem]

Thanks for the responses.

I also have access to the main well line going into the house (looks like around 3/4"). Should I tap into that one instead? It is before my water tank so that would mean the well would turn on every time water is used from that branch. Is that bad for the pump or is it no big deal?

 

[speedbump]

Unless you have a check valve somewhere and a pressure switch on the wrong side of that check valve, I don't see what difference it would make to the pump. It should still allow the tank to drop down to the switches turn on setting before the pump has to come on. So to answer your question. The pump coming on and off a lot is bad for it.

 

[Raindem]

Unless you have a check valve somewhere and a pressure switch on the wrong side of that check valve, I don't see what difference it would make to the pump. It should still allow the tank to drop down to the switches turn on setting before the pump has to come on. So to answer your question. The pump coming on and off a lot is bad for it.

I'm not sure I understand your answer.

My tank and pressure switch are located in the garage. I plan to tap into the well line as it goes into the garage, before it gets to the tank. Thus my splice in point would be unregulated by the tank pressure switch.

Are you saying it doesn't matter, that the branch will still draw water from the tank just like any other in the house?

 

[phishfood]

Your tie in will be supplied from the tank, unless there is a check valve between the tank and your tie in.

 

[Raindem]

OK, now I got it. If there is not a check valve then it will draw water from the tank. If there IS a check valve then my setup won't work because the line won't be under any pressure (unless the tank pressure drops due to other usage).

I don't think there is a check valve because a couple months back we had a break in our line near the well head, and it flooded our neighbor's yard in addition to ours before it was discovered.

Thanks again.

 

[speedbump]

The flooded yard might have been because the pump was already running when the line broke. The broken line would have kept the pressure switch from turning off the pump. If you do have the check valve between your tee in and the tank, you will know it because the only time that tee will get water is when the pump is already running.

 

[Raindem]

That's good information.

I have one more question related to this project if I may. The grade slopes downward along the path that I'm going to run the water line. Not a big drop, just a gentle slope. How do I get the new pipe at the right angle?

 

[phishfood]

Use a 90 degree fitting to turn sideways, then another to turn back in the direction you are running the pipe. When you glue the second 90, twist it to point downslope.

 

[havasu]

Just a thought but using 45's would keep the flow at its optimum, wouldn't it?

 

[Raindem]

Perfect. I can't believe I didn't think of that.

It turns out to be a moot point though. I tested it this morning and there is indeed a check valve between my intended tie in spot and the water tank. Thus no pressure at the Tee when the tank is full.

So it's back to plan A, tying into my 1/2" spigot. Since it's a few feet away from the main trench I'll have to use a couple elbows anyway, so I can go ahead and twist them to the correct angle as you guys suggested.