Help With Burried Water Lines

[CurlyDave]

This is a two-part question:

We are building home on fairly mountainous property.

The well is going to be located about 400 lineal feet from the house and approximately 100' lower in elevation (~50psi just from gravity).

There will be a power transformer within 30' of the well, specifically to power the pump, my future shop and an RV pad.

The water will be routed to the house through pipes laid in a trench from the well to the house.

My thought on what the trench should contain would be two 1 1/2" PVC water lines (a primary and a spare) to feed a pressure tank at the house, two 1" water lines (again a primary and a spare) to bring water down to the shop & RV pad from the pressure tank at the house, and a 3" conduit for the signal wire from the pressure tank to the well pump. The well is close to the property entrance and this conduit would also contain signal wires and intercom wires for a future automatic gate.

My contractor has suggested that I use PEX instead of PVC. He would run the PEX in a 3" conduit (one line up and a smaller one down, separate conduits) which he claims would allow me to pull a new line if the original one ever deteriorated or failed.

My thoughts are that a PVC pipe and a spare would be less costly than a PEX line plus a conduit, and the PVC has stood the test of time, while PEX is still fairly new. For an interesting discussion of PEX see Plumbing World on PEX .

OTOH, I am not an expert on this and would like to get advice from anyone who really knows.

The second part of the question is the pump control scheme. My thought is that by running a smaller line down to the shop & RV from the pressure tank in the house, I can use a "standard" control scheme where low pressure in the tank turns on the pump, which then runs until it has filled and pressure has risen, which turns off the pump. The shop and RV would just be another load on the water system, exactly like a bathtub or washing machine in the house. The incremental cost of this would only be 800' of 1" PVC pipe laid in the trench, which is ~ $250 plus labor. Since other pipe is going in the trench, the incremental labor would only be connection of the pipe sections.

The contractor "thinks" that I could tap the 1 1/2" line feeding the pressure tank for the shop & RV. I believe that a properly-installed line would have check valves which would prevent water backflow in that line. He says I could overcome that with a special pump, and I see costs rising. Other wells in the area are 200-300' deep and a standard pump will be $3000-4000. If the special one is 10% more, I think the return line is closer to standard and much more repairable in the event of a failure.

He also claims that another possibility would be a second pressure tank at the wellhead. I do not understand how one pump can be controlled by two pressure tanks, but am willing to listen if anyone can explain that.

Any advice here?

 

[EddieWalker]

Dave

You're in territory that I've never heard of, especially with PEX, but I'll share my thoughts with you for what it's worth.

I'm a real bag fan of using proven, traditional methods for my personal stuff. No way would I run a new product on my place. First, I don't rely or trust what other say until it's passed the test of time.

There are allot of minicipalites and water districts out there that ran Black Poly water mains because of the claims of how good it is. Time has proven it to be totally unreliable and expansive to maintain. Crews are on duty 24 hours a day to repair waterline breaks in it because they are so common.

PEX might be great, or it might be the next Black Poly.

The other concern with it is repairs and available materials that are compatable. Ten years from now can you still get a union for it if it gets broken???

I like PVC. Simple, cheap, proven and you can get it just about anyplace seven days a week. That's another important consideration. You get a break at midnight Saturday night and cost isn't near as important as getting it fixed. If you can run to Home Depot first thing in the morning and get a Union of some sort, that's priceless.

As to running spare lines. WHY??????

If a line breaks, dig it up and patch it. Odds are that if it breaks anyway, the line right next to it will to. No water utility runs spare lines and I've never heard of a reason to do so either. Use Schedule 40 PVC with purple primer and clear glue for your joints. If you have allot of rocks, backfill with sand.

My experience with city jobs and large water mains from Santa Cruz to Livermore and up to Napa has been that they all require at least a foot of sand around every water line.

I don't know about code for you, but you might not even need sand, or maybe you only need a few inches to surround your pipes. One thing that suprised me here is they DON'T use sand in their lines. Lucky me. /forums/images/graemlins/grin.gif

For the idea of using multiple lines in the same trench. Be careful about this. Most places wont let you mix electrical lines in water lines. It's not that anybody is worried about them mixing or something like that, but for repairs or taping into the water lines.

Odds are you will never need to dig up the line and repair it, but if you ever do, and the water line is leaking water all over the place, you don't want to have to deal with the electric lines right next to it. Even worse, you don't want a contractor or anybody else digging up the water leak that is right next to the electrical line.

Putting a conduit under a road is a good idea for down the road. Cap it and mark it so you can find it later. Running the entire line is just extra work that you may or may not have a use for. You also don't know what you will need down the road. It's just guessing right now and it's really easy to dig another trench when you actually need it.

Finally, make sure to make good maps. Not only where they are, but how deep. Ten or even twenty years from now your memorry might not be as clear as it is today.

Good luck,
Eddie

 

[CurlyDave]

As to running spare lines. WHY??????

I think spare lines are cheap insurance. Sure, a common mishap can happen, but there are also individual failure modes. I would easily pay $250-350 now for even a 10% chance of not digging up the trench at some point in the future. Digging up the trench will probably break all the lines in it, and finding a leak is never easy.

Most places wont let you mix electrical lines in water lines. It's not that anybody is worried about them mixing or something like that, but for repairs or taping into the water lines.

I can't do that either, but low-voltage signal lines are allowed. This conduit does not carry power, only the signal that throws the relay which turns on the pump. Depending on the system it is either 12 or 24 volts. I need a relay in the system because of the long distance from the house to the well. There will be a power company transformer within 30 feet of the well.

Sounds like you are in agreement on the PVC vs. PEX issue though...

Thanks for your thoughts.

Dave

 

[Farwell]

Eddie,
Great information. The only thing I would add is to run tracer wires with all your under ground pipes that may be hard to locate in the future.
Farwell

 

[CurlyDave]

The only thing I would add is to run tracer wires with all your under ground pipes that may be hard to locate in the future.

What is a tracer wire?

This sounds like a good idea, do you have a link to how I run one?

Do I just bury any old wire alongside the pipe (my inclination would be a bare stainless wire) or are there special requirements?

Thanks,

Dave

 

[valleydweller1]

How many pumps do you plan to install? 50 psi is a lot of pressure loss for a well pump that's only capable of 70 +/-.

If it were me (and it's not) I would put the pressure tank at the well along with the control box. I would then put a booster pump at the house to boost the pressure. I would put a spigot at the wellhouse for your water needs there.

The problem you will have with running a pipe back down from the house is that the pressure you lost on the way up will be gained on the way back down. So, if you have a booster at the house to bring the pressure to 60 psi and then add another 50 psi of head pressure you will have 110 psi back at the bottom of the well. While that's technically feasible, it's hard on whatever equipment you put in at the bottom (including a sink/toilet in the future shop).

On the other hand, I could be wrong.

What does your well guy say?

 

[CurlyDave]

How many pumps do you plan to install? 50 psi is a lot of pressure loss for a well pump that's only capable of 70 +/-.

That must be a different kind of well pump than in common use around here.

Wells go up to ~500' in this area. The pumps are submersible and multi-stage. In additon to being multi-stage, they are multi-thousands of $. I am trying to keep the number to one for that reason. There is no difference between elevation change inside the well and elevation change external to the well.

I am hoping for water at much less than 500'. My neighbor has a well at the same elevation as I am planning, and from the local topography I think I will be tapping the same strata as he is, but about 300' away. His well tested at 50 gpm at a depth of 180', so drawing from the same strata is not going to hurt him. But, if my well is 180-200', I will need at least 100 psi just to get the water to the surface. 100' up the hill is another 50 psi.

I worked out the cost for electricity to boost the water from the wellhead to the house and it is only about $1 per 1000 gallons.


The problem you will have with running a pipe back down from the house is that the pressure you lost on the way up will be gained on the way back down.

Absolutely true. I was planning to put in a pressure regulator. One large enough for a house is under $100 at Home Depot.

 

[inveresk]

Dave,
I read the report in the link you provided and have not come across any problems with alkathene or pex in relation to doses of chlorine. Doesn't mean to say this isn't an issue - it's just not one I've come across.

Polyethylene piping has been the norm in europe since I've been a practising architect, now over 30 years. Anything undergound is normally alkathene (polyethylene) and if plastic pipe is used above ground, it's normally pex (again polyethylene). The last two homes I built before coming here in 2003 were high end and both had the usual alkathene undergound and pex above. The pressure delivered to the house via the main was 9 BAR and I had to step it down to 3 BAR inside with a pressure reducing valve so the furnace, water pressure vessel, etc. were not overstressed. Both houses had push fit connections on the pex for all hot and cold services internally, pretty much industry standard.

When I visited my local builders supply company to get u/g water pipe for the new barn I'm building, all he had was pvc which I'd never seen before. Although I haven't yet undertaken a formal comparison of respective properties,my initial impression was that it was inferior to the polythene I'm used to, less flexible and the walls seemed more brittle, so I ended up not buying it. I'm installing all plumbing and drainage on the barn myself. I've yet to undertake a search here to see if alkathene is available but if it is and it complies with code, I'll be using it instead of pvc. I'll use pex above ground.

It's not an issue for everyone, but one of the problems with pvc is its environmental credentials. There are a number of reports on the issue. Here's one of them. A web search will soon bring up others.

pvc

To add an addendum, Eddie is right about the black polythene - it's rubbish - but the Alkathene and PEX I know are very different.

 

[LarryRB]

Edie isn't familiar with PEX, My whole house is PEX for the heating system,, that is, forced hot water,,, PEX is almost totally bullet proof. You are correct, to run PEX inside schedule 40 pipe,,, A spare pipe is also a smart move... We have to lay red tape with black lettering,, (same tape in yellow that cops use at a scene, "do not cross".. Here in New England, with a gazillion rocks,, they do work their way upwards,. In doing so, they will shear black ply pipe, and if not in sch 40, the obvious happens,, Go find the break...

 

[dubba]

</font><font color="blue" class="small">( What is a tracer wire?
)</font>

I believe a tracer wire is a wire run along with the pipe that the end comes to a known location so that the locater guy can hook his ground sensor to it.

For my personal stuff I put aluminum foil about 10" down so I can find it easily with the metal detector. I find my memory is so short, after a month or so, I can't remember exactly where that line went as I have to make so many detours to go around exposed ledge with my pipe runs.