New water line - best practice

dinotoad · Thu May 13, 2010 1:29 am

I plan to re-run the main water line to my single-wide mobile home in Flagstaff Arizona. I would be curious to know what is considered best for this. The current line looks like a mess. It seems to be part pvc, part washing machine hose, and I don't know what else is inside the insulation.

I don't plan going all the way back to the main. I think the main line was replaced at some point. I want to dig down a bit and then run a new clean line to the mobile.

What is best pipe? Is it PEX? How about shut-offs? Should I install some sort of box where it come out of the ground? I was thinking about reburying the line in about 2 feet of vermiculite to insulate it and make it easy to uncover. I am also planning on heat taping the line.

I appreciate all tips and advice!

JD · Thu May 13, 2010 5:48 am

PEx is not for exterior use. I would use galvanized pipe from the service into the skirting, then run 10' of galvanized pipe below the side of the home towards the water heater. From there I would use PEx. Hardcore plumbers may say that copper is best, but PEx is holding up much better in the hard water zones in my area. You can use a manifold system if you like. I prefer just replacing the existing plumbing with PEx and using shut off valves at the point of use. Manifolds are usually installed with access from inside the home where they are easy to get to when you need them. You could install a mainfold (with or without shutoffs) under the home and then shutoffs at the point of use, but then what's the point? About the only acceptable location inside the home for a box to hold a manifold system is the utility room. No one wants this manifold showing in their bathrooms or halls. The utility room should be right next to your water heater compartment, where you could have shutoffs for both hot and cold. Also, if you are using a contractor to install your plumbing, manifold systems will cost more.

JMO
JD

Greg · Thu May 13, 2010 4:26 pm

Here in the north east we think nothing of running PEX from the ground shutoff through the home. PEX is very forgiving when it comes to freeze ups. If you are running under ground I would go copper. Greg

dinotoad · Fri May 14, 2010 3:07 am

Greg wrote:Here in the north east we think nothing of running PEX from the ground shutoff through the home. PEX is very forgiving when it comes to freeze ups. If you are running under ground I would go copper. Greg

That sounds good to me. Do you install some sort of box in the ground or does the pipe just come out of the ground (say in copper) and then transition to PEX?

I was thinking of some sort of box or maybe just a wide pipe to enclose the pipes. Then a hose bib and then a shut off and then PEX to the hot water closet. Should the PEX be curved to help compensate for settleing?

I don't think I could ever install galvanized after seeing it replaced in my former house at great cost. That stuff just corrodes away (OK, after 40 years).

Greg · Fri May 14, 2010 5:45 pm

We usually install a section of 12"-24" corrugated pipe about 3' long to make a well. end the copper at the bottom with the valve and tie the PEX in there. I leave enough slack since PEX is flexible ther is no problem. I would run a 3/4" line for a main line into the home. Don't forget to install a main shutoff INSIDE the home in a place easy to get to. If freezing may be an issue add insulation. Greg