What to use for water line out to detached garage?

EddieWalker · Oct 24, 2005

I've read this post a few times and keep thinking I'm missing something. It must have something to do with your location, cause none of the advice I've read is what I'd use or even standard practice in allot of areas I'm familiar with.

Copper is used in the big city areas with Union Contractors. I've remodeled quite a few bathrooms. I've never done one yet that didn't have a leak of some sort at the tub valve. It is usally a very small leak, but over 30 or more years, the sub floor is rotted out.

Of course, if it's not leaking, I wouldn't be there in the first place, but it does influence my avoidance of copper.

As for the black poly, it's advantage is how fast you can lay it. I've worked with a few water districts that used it, and it's a full time job, 24/7, for crews to dig up and patch holes in it from ruptures. I don't know what grade it is, just that I'd never use it anyplace after your meter. If your on well water and don' t have to pay for the water if it breaks, that's your choice.

You said your running water from your house to a workshop. Is that right? What water demands will you have? How big is the line coming into the house? How many open valves will you have at one time?

For feeding a house, I'd go as big as possible. One inch is great, but I just ran 1 1/2 inch to my place, but I've got some unique requirements.

From your house to a workshop, I'd run 3/4 inch Schedule 40 PVC. Use purple primer and clear glue. Nobody around here will allow you to use anything but clear glue.

3/4 is plenty for a bathroom and several water spickets. Many houses are fed on a 3/4 inch line and nobody even notices it.

Rule of thumb on sizing pipe. For every half inch increase, you have 2 1/2 times the volume. Putting larger pipe in will allow you to store more water in the pipe, but over time it will go stale on you and it will start to taste bad if you want to drink it.

Sorry if I steped on anybodies toes, I'm not trying to antagonize anybody here, just offer my opinion based on my experiences in the areas I've worked.

Eddie

Cowboyjg · Oct 24, 2005

I saw that you were considering PEX. I was going to suggest you look at that. To me the best part is that it won't burst when temps get to freezing. My place in TN had CPVC. Although I winterize, over time through the previous owners being full time, the pipes "Jes give out" Had the house re-plumbed with PEX. My plumber gave me a length about a foot long capped at both ends and filled with water. I placed it in and took it out of the freezer for about a week. Absolutly no signs of compromise. Can't say enough good stuff about it.

dooleysm · Oct 24, 2005

Everything I've seen over the past year is right in line with what Eddie said. With the help of my wife and father-in-law, over the past year I've built a house and pole barn. We used 1" pvc from the meter to the house (about 300 feet). That gives us more than enough water pressure and volume. For the barn, I tapped right off the 1" line going into the house to provide water for 2 frost free hydrants. That is too much pressure. You open those hydrants up and it's like a fire hose.

I'd go with no more than 3/4" pvc from the house to the barn, if I was in your shoes.

LBrown59 · Oct 24, 2005

( The local plumbing inspector told me that the black stuff "just barely" makes code,
if you look at it it's only rated for 100 psi
as opposed to 2-300 psi for PVC. PVC is probably a better long-term choice. )

=================
Water pressure should be between 40 and 60 psi.
So the black plastic rated for 100 psi is more than adequate.
If your water pressure is greater than 60 psi a pressure reducing valve needs to be installed at the beginning of the line to bring the pressure down to specs..

In 1971 I put in 300 feet of water line and 500 feet of gas line here.
I used the 1'' black plastic water pipe rated at 100 psI. for both the gas and the water.
The water line has a pressure reducing valve to bring the 80 psI pressure at the water meter down to the required 40 to 60 psI range.
It's been here for 34 years without any problems.

Highbeam · Oct 24, 2005

There's nothing magical about 60 psi. We have 70+ in the city I work in and I have gauged just over 100 on a home in an adjacent city. Most well systems have cut offs at 60 though and that is sufficient.

Larger pipe won't increase the pressure over the static pressure. There is no maximum line size. Oversized lines mean more staleness but not more flow or pressure from typical fixures.

We use the standard 200 psi black PE pipe for services and ductile iron for mainline at work. I have been very impressed with the black PE pipe and have never seen it leak anywhere except the fittings. I reommend the 200 psi black PE in one continuous run.

Highbeam · Oct 24, 2005

Dargo, the guy is not installing a city water main. This is a line to a garage and what I am saying is that after a certain size say 1" or 3/4", performance through the typical fixtures in this GARAGE will not be changed. A 12" main will not allow any more flow or pressure through the guys 1/2" hose bib than a 1" service line. That's the serious part. The one post that made it sound like you can oversize the service line was mistaken and I wanted the poster to be at ease with oversizing within reason.

Highbeam · Oct 24, 2005

What happened to your post Dargo? The one where you wanted to school me on physics and so on....

EddieWalker · Oct 24, 2005

Highbeam,

I was trying to respond to Dargo's post as well, but it wouldnt' work. Maybe he reread it and realized he didn't want to post what he'd said.

Water mains are sized to accomodate the volume of the homes they service. They continue to downgrade in size to maintain preasure with the need preasure to provide everyone with enought water.

The problem with too much water preasure, typeically 100 pounds or more is it will cause the valves to leak. The toilets are really bad for this. I've been told you can lose thousands of gallons of water every month through your toilet by too much preasure.

If your place is down a hill, water preasure will increase, sometimes by a large amount. I had to install a preasure reducing valve on a house like that. I was loosing water throught the toilet and had 120 pounds of water preasure, but it was 70 pounds at the house on the top of the hill.

Stale water comes into play when you put a larger diamater pipe in than whats supplying it. Lots of homes have a 3/4 supply line. Putting a 1 inch feeder line on that will work as a storage tank and go stale over time.

Theirs all sorts of black lines that I'm not familiar with. I just don't like them as a general rule because of the problems I've seen and heard about them. I feel the same way about thinwall PVC, it sucks. Go with Schedule 40 and you'll have good results.

Again, I hope nobody takes offence to my disagreeing with them, I'm just offering my opinion based on personal experience. I'm not a plumber by trade, just a builder who does allot of different things.

Eddie

LBrown59 · Oct 24, 2005

The short comings with PVC in your counrty is freeze and transition to other materials.
1* The male and female connections are what has given trouble in the past. 
/././././
1* That's because they are steel like the fittings for steel pipe.

To much water pressure can result in leaky sink and bath room futures.

mffarmall · Oct 24, 2005

You can use PVC 1" should be good. Make sure to use a high quality high presure. It should be white in color. I like the 10' sticks that have a cupling on one end. Glue them together. Then use a 10' of copper that enters the building with a grounding rod and copper line from inside the structure. Unless you are going to have a frost free fosset. I like to use 4' line.