What to use for water line out to detached garage?

jim_wilson · Oct 22, 2005

My summer project for the tractor was to dig out a hole for the foundation for my new detached garage. I finished the hole, got the permit for the foundation, and lined up a contractor to pour it, and then it started raining and the hole filled up - with 2 feet of water. And it isn't going down. So now I am off on other projects since I don't think the thing is going to drain before the weather starts getting too cold to do anything around here. The water table is high because we probably had 20 or more inches of rain over the course of a couple of weeks.

The project I chose was to waterproof the rear foundation wall of the house - which ties into the garage project because I need to run some conduits thru the wall for electrical and data cables. And I need to run a stub for a future sewer service out to the garage - and I need to run a water line. The only thing I am not sure what to use for is the water line. The original one coming into the house is a soft copper line that has been there for 45+ years now and seems ok. I had heard that the material of choice now is a plastic line. Anybody out there know what I should be looking for to do this? I wasn't planning on doing this work until next spring or summer so I hadn't really researched the choices yet. I am going to to tie in to the water service inside the house and just extend it out to the garage.

Farwell · Oct 22, 2005

In Michigan we use the black plastic pipe that comes in a roll. We bury it below the frost line which is 42 inches in my area of Mid Michigan. Many of us are on wells, not sure what the rules are for a city water systems. In California I used the ridged copper pipe for the house main supply from the city and the softer ridged copper for the rest of the house. The thing I did not do when I ran the pipe in California and wish that I had was to use 1 inch pipe for the main instead of 3/4 inch. I had plenty of pressure but not the volume that I wanted for a hose bib at the back of my property that caught on fire every 4th of July from kids and their fire works.
Another thing that I do on all of my water pipes is to use ball valves as shut off valves rather than gate or globe valves.
On your garage, think about raising the floor of your garage rather than digging out for it if your water table is so high. I had about 14 inches of sand for the base of my pole barn to help keep water out of it and you may need to do something similar. If you are going to heat the garage you may also want to think about putting 2 inches of foam board insulation and a moisture barrier under your cement floor.
Farwell

mrcaptainbob · Oct 23, 2005

Farwell sure is correct on those assesments! My last house had the 1" black (nylon?) feeding the house. THis place has 3/4". The pressure is adequate, but the volume is pitiful! In the throws of replmbing this ol' house and am using 1" every chance I get. The last thing will be a new well with a MUCH larger supply! You're doing all the right things. Make sure to provide 'tunnels' of PVC through the wall to fit the items through. When you run your items (electric, water, etc.) foam them in place. You could also run PEX for your potable water. Works well for hot and cold.

valleydweller1 · Oct 23, 2005

The local plumbing inspector told me that he 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.

inveresk · Oct 23, 2005

Best pipe for water supply is alkathene. Size it 1" or above.

kayssupply · Oct 23, 2005

Let me start out qualifing my advice, I am a liscensed plumber of 25 years. All the above advise is pretty much dead on. I would add that the best is always copper. I personally have a rule of thumb, if a water line is under 100ft I use copper. Lately I have had to change that to 50 ft due to the terrible increase in cost. I personally used 1" roll Poly pipe for a recent pole barn project. The point I am getting to is that there are several grades of poly. I never use any rated less than 200#. It isn't usually a stock item but in pump counrty it should be available somewhere. It stands up to rocks , freeze, and even a good tug by a backhoe. I use brass insert fittings to splice and connect and always double clamp with " all SS" clamps. The bolts are sometimes not ss, be sure to check.
The short comings with PVC in your counrty is freeze and transition to other materials. The male and female connections are what has given trouble in the past. There is a brass compression fitting that has clamps to keep the pipes from pulling out that has just become popular around here. It has been a real life saver for me.

jim_wilson · Oct 23, 2005

Thanks for the replies. I figured my choices were pretty much either the soft copper or plastic of some form or another. After doing a little bit of research I found that the PEX type tubing that is used for plumbing radiant heat type floors and in house plumbing also appears to be a candidate. Copper appears to be the time proven choice though.

The actual garage floor is going to well above the water line. The garage is being built in my back yard which is on a little bit of a slope. It is the lower part of the foundation hole that has the problem - it is full of about 1 1/2 foot of water. It appears that after all the rain we had the water table is just very high around here. I don't anticipate it going down any time soon because as I write this it is raining out again. I thought about the foam under the floor idea too - I have pretty much firmly decided against it though. After doing some recent research that backs up some personal experience I have had with termites. All of the blown foam type insulations appear to have something about them that actively attracts termites. A couple of years ago while doing some extensive renovation to my house I found I had termite damage to the house right under the front door area. There was some of the Dow pink foam insulation right under the door area and it was riddled with termites. They had eaten into the wood - but actually seemed to prefer the foam for some reason given the amount of termite holes they had eaten into it. The last thing I want to do is build a structure with anything in ground contact that actually acts to attract termites.

hayden · Oct 23, 2005

I've used 1" poly pipe with success in the past, but I discovered what others have - there are a few different grades. The stuff from Home Depot is the lightest grade and is rated much lower than the good stuff. It also kinks very easily, and can crack if it does puncture. For all these reasons, I recommend to trip to a commercial plumbing supply house for a roll of the good stuff.

willfick · Oct 23, 2005

The squirrels absolutely love the black plastic stuff, too. I had some not buried enough on a sprinkler project and some leftover; they chewed it up voraciously. I don't know if it's the taste or the feel, or just the urge to destruct.
Wm

tawilson · Oct 23, 2005

I'm surprised to hear that. I've got a campground with hundreds of feet of it just laying on the ground through the woods. I get the occasional leak, but never have a problem with anything chewing on it, not even porcupines. And I have found the 160psi stuff at Lowes.

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.