HELP!!! Plumbing Issue, Main Water Supply Line

[Foxtrot1]

This one is a little off topic, but I thought someone on here could help with an issue I'm having.

I'm running a new waterline for our house. It is 1800' from the meter to the house. Little to no elevation change. I had the county install a 1" meter at the road. They tapped an 8" line on the highway that has 90-100 psi of water pressure. I have a bridge crossing 800' from the meter. The line is intact from it to the house (1,000'), so I had planned to tie into it and leave it intact. That waterline is 1" PVC.

So, here's the tricky part. I was going to run PEX to minimize joints along the 800' section. I had the local plumbing shop quote 1 1/4" pex, but it is 3x the cost of 1" ($2,450 for 800" pipe and fittings). Also I have to pre-order all fittings. The plumbing supply shop will let me borrow their pex tool (mine will only crimp up to 1"). If I order the PEX online, I will have to buy my own larger crimping tool. (Not sure what kind of bear it will be to crimp, the plumbing supply shops tool had a nut that you use an impact wrench to crimp the bands. I would probably have to get a hand held unit. I have literally 4 crimps to make)

Sooo... is it worth the extra hassle and $$$ to run the bigger pipe 800'? Obviously the bigger supply line will carry more volume and higher pressure over the 800', but I am still limited on the farther 1000' to the house. The house was built in 1978 and had a 3/4" meter and 1" supply line that whole time. I have no idea what their water pressure was like. The engineers or plumbers at work can't say exactly what the PSI will be at the house with either set up.

Any of you guys installed long waterlines, or have one to your house? what size line did you run? pressure issues?

 

[warmer]

The ID of 1" PEX is smaller than the ID of the 1" PVC. You will lose flow with that 800' of 1" pex. I would suggest the 1 1/4 pex with expandable fittings.

 

[diamond hitch]

The formula for flow is Q=AV. If you reduce the area you will have to increase the velocity to maintain the flow rate. At some point you may see cavitation if the area is too small. You will also have considerable friction losses. I usually only work with big pipe. I ran 2 inch pcv to my barn and then stepped it down. I don't have any tables for friction losses for pvc or pex. Things to consider.

 

[Bigjay73]

How much will it cost to run the 1", not have it work right, and then replace it with 1¼? 1800' is a long damn way, Im honestly surprised 1¼ is big enough, but hydronics is not my strong suit.

 

[Elkmagnet]

The inside diameter of the fittings and length of run would lead me to use something larger
I ran 1.5" polly pipe for 100' run from my well.

 

[hank4elk]

You only have 1" at source anyway. 1800' is a long ways.... I would stick with full 1" to the house. You will not increase volume past the 1" meter,just don't restrict flow with joints & changing sizes.
But then again,I'm not a certified plumber............lol

 

[Bigjay73]

Having 1" at the source will not force him to use 1" to the house. You will still get greater volume with a larger pipe, unless the source was run in 1" for some amount of distance

 

[Elkmagnet]

Having 1" at the source will not force him to use 1" to the house. You will still get greater volume with a larger pipe, unless the source was run in 1" for some amount of distance

I agree.
1" pvc is measured I.P. 1" pex is measured C.P. the pvc is larger. you will be further restricting by going with 1" pex. Even with 1000' of 1" pvc you will have a measured difference if you up the size for the last 800'. 800' of 1"pex is a lot of friction.

 

[SD_Prairie_Goat]

Just my general thoughts:

• Depends on how much you want to run in your house really. You will see a very real pressure drop when using water due to the length of that run along with the diameter of pipe. Just be aware that running the garden hose may make it a light trickle in the shower
  • I'm an electrical, so I don't know the pressure drop calcs without googling, but same to wire's voltage drop is water pipes pressure drop. Longer the run the larger the drop all other things staying the same. You overcome this with larger pipe (or larger cable for electrical)
• If it were me I would use the largest pipe I could swallow paying for.
• Running that section as larger pipe will help your pressure drop. Obviously it is a portion of the run, so it will not be able to fully overcome the pressure drop you'll face, but it can help.
• Also, not a plumber what so ever, is PEX better in the ground than PVC?

If you are really worried about it, I can ask some old coworkers to run a quick pressure drop calc for you on this and see what they come up with.

 

[bigjohn]

I have started running my DIY plumbing projects , both irrigation and domestic water, through a free on line program called "Pressure loss in straight liquid lines". 1800' is a long ways in a 1" to 1 1/4' line. Mr Google says that the average household water demands are 6-12 gpm. Using 9 gpm, you would have 57 psi drop with 1" and 18 psi drop with 1 1/4". If you turned on a hose bib at 12 gpm in addition to household needs, it would result in a 289 psi drop in 1" and 92 psi drop in 1 1/4". You might want to figure your water needs and plug those into the formula to decide what size water line you would be happy with.

 

[jeremys4]

Run mws the black pipe or look for someone with a fusion machine so you won’t have any fittings 1-1/4 cts is the same id as 1” ips I would at least run 1-1/4 ips should not have the flow issues or much line static.

 

[88man]

I would size accordingly but sch 40 pvc belled is about 75 cents a foot in 1.5 inch. Im pretty sure your gonna need either 1.5in or 2 in to keep the velocity below 6fps and to reduce the friction loss.

 

[Foxtrot1]

Thanks guys, great info. I'm gonna back up and look at 1.5" pvc. Similar in price to the 1" pex.

One of the attractions to pex was ability to buy in 500' and 300' rolls to minimize joints. I also have a bridge to cross that will have about 50' of pipe exposed. I had planned to insulate the pex and case it in PVC painted black for the crossing. Figured the pex would be more forgiving in the winter. Our frost line is only 6", so cold isnt a huge problem, but we do get a couple of weeks of freezing weather.

As far as water use, it's a 3 bedroom, 2 bath. Just 2 of us now, but could be more later. No outbuildings, but we do have a pool that will require a spicket intermittently. The county said we should be getting 50 gpm through the meter where we are.

 

[dcopas78]

I'd use 2" HDPE, SDR 11 which I think you can get rated at 200 psi. It's way cheaper and you can get it in 500' spools. We used it to replumb the fairgrounds many years ago and haven't had a leak yet except for in transitions to meters. It is tapped in to a 8" c900 line that has 95 psi on it. As someone mentioned, find someone that has a fusion machine to do connections, get them to weld in a hdpe to pvc transition at your house and do what you need from there.

 

[Addicting]

Call the nearest well digging company. They have hundred feet rolls of flexible 1.5-2” pipe specific for your issue. They install it every day and Will get you squared away better than a Internet forum.

 

[theddguide]

I would recommend 1 1/4 or bigger pex or poly with expandable fittings as already noted. For what it's worth, PVC can crack, become brittle, and therefore spring a leak, much easier than pex.

 

[Foxtrot1]

After looking around online, we decided to go with 1.5" pex. Able to get it drop shipped for about $1.25/foot, and a crimping tool for $120. I would rather have used local vendors, but price difference was crazy.

If pressure is a problem, I can add a pressure tank and pump in the basement. Fingers crossed.

Manager at the water works thinks I'll be ok. He thinks we may need a pressure regulator at the house. I hope he's right.

Thanks for all the help guys!

 

[SandyCreek]

you always have to upsize with pex as the wall thickness takes away from the diameter. personally i would run at least 1-1/2 or 2" that way you know you will have the volume for anything that changes down the road. I also would either use a fusion machine or uponor expansion pex. the crimp pex is trash and theres no way id put it underground.

 

[Irrelevant]

After looking around online, we decided to go with 1.5" pex. Able to get it drop shipped for about $1.25/foot, and a crimping tool for $120. I would rather have used local vendors, but price difference was crazy.

If pressure is a problem, I can add a pressure tank and pump in the basement. Fingers crossed.

Manager at the water works thinks I'll be ok. He thinks we may need a pressure regulator at the house. I hope he's right.

Thanks for all the help guys!

Why PEX and not hdpe?

 

[Foxtrot1]

Why PEX and not hdpe?

Honestly a combo of things. I'm more familiar with working with pex, I used it to re-plumb the whole house. It's supposed to be tougher and I'm worried about the bridge crossing freezing at some point. If it does, hopefully it wont be an issue with the pex