a Plumbing question

[Aintlifegrand]

I have a question about water supply lines...would it be better to use 1/2" copper pipes or 3/4" and what decides that...distance? number of fixtures? Here's the scenario...I am about to run supply lines from water heater to bathrooms ( 3 full baths/1 upstairs and 2 downstairs all together). The distance is from the laundry room where the HW heater is is 42 feet to the bathroom areas which are all together. The kitchen and laundry room are together on one end of the house and the bathrooms are on the other end . Should I use 3/4 or 1/2..does it matter...and why? oh one other fact...I am not sure exactly what I am doing if you couldn't tell Thanks.

Stephanie

[Danaus29]

Check the cost for running each. In most cases 1/2" is much cheaper than 3/4". You do have the consideration of the opening size for your fixtures. Going from a smaller diameter pipe into a large opening will reduce your pressure a bit, I don't know if it would be enough to be a concern. But with a 42 foot run, 2 pipes, you really need to look at the cost. IMO

[cfabe]

I don't know the rules of thumb for plumbing, but water in a pipe is just like electricity in a wire, if you undersize the pipe for your flow requirements and distance, you'll have poor pressure. Just like you need to size wire appropriately to have acceptable voltage drop over a run, you need to size the pipe too. I'm sure there are tables to tell you what's required. As a guess I'd say run 3/4 for the long run between the water heater and the bathrooms, then tee it off to 1/2" to run to each fixture. If you undersize it you'll have pressure problems, particularly when two fixtures are in use at one time (two showers, or flush the toilet whlie someone is showering). If you have any bathtubs you may want to run 3/4 to the tub so that it will fill quickly.

[jross]

I would run a 3/4" as a trunk line, then run 1/2" off that to each facility. If your water has any scale forming deposits, a 1/2 "supply line will narrow more quickly than a 3/4" and deposits will settle in the bottom third of the 3/4" line. More expensive yes, but not as expensive as replacing a lot of1/2" piping.

[Danaus29]

According to dh, smaller diameter = greater pressure but less flow. Something I didn't consider. But still it can't come through any faster if the opening for the sink or tub is smaller. When I get a chance I'll ask him.

Don't they make a plastic for indoor potable water? You could use that on the cold water side if cost is a big factor but use metal on the hot water side. The hot water not only leeches chemicals from the plastic but can soften the glue used to hold it together.

Now if there is a good chance the water line could freeze, dh would tell you to use 1" heavy duty stainless. That's what he put in our basement but only up to the water heater. From there it is a mish mash of washer hoses, copper, and pvc.

[Micahn]

Originally Posted by Aintlifegrand

I have a question about water supply lines...would it be better to use 1/2" copper pipes or 3/4" and what decides that...distance? number of fixtures? Here's the scenario...I am about to run supply lines from water heater to bathrooms ( 3 full baths/1 upstairs and 2 downstairs all together). The distance is from the laundry room where the HW heater is is 42 feet to the bathroom areas which are all together. The kitchen and laundry room are together on one end of the house and the bathrooms are on the other end . Should I use 3/4 or 1/2..does it matter...and why? oh one other fact...I am not sure exactly what I am doing if you couldn't tell Thanks.

Stephanie

It is the number of fixtures not the distance.
From the sound of things this is a new home ? Remember it may cost a few bucks more to start with but over time you be glad you done it right.
Figure 3 cold water fixtures on a 1/2 line and up to 8 on a hot line. For 3 full baths I would run a 3/4 hot to at least the first one and then split it into 2 1/2 lines going to other 2.
The cold I would run a 3/4 all the way to the last bath. I am sure you have heard of someone flushing while someone is in a shower? Well be in that last bath when someone flushes in one of the others and you will be glad to have that 3/4 line lol.

So you know I was a master Plumber most of my life and took over the family company until I got hurt and can no longer work. Plus was a teacher at a plumbing apprenticeship school for many years.

[Micahn]

Originally Posted by Danaus29

According to dh, smaller diameter = greater pressure but less flow. Something I didn't consider. But still it can't come through any faster if the opening for the sink or tub is smaller. When I get a chance I'll ask him.

Don't they make a plastic for indoor potable water? You could use that on the cold water side if cost is a big factor but use metal on the hot water side. The hot water not only leeches chemicals from the plastic but can soften the glue used to hold it together.

Now if there is a good chance the water line could freeze, dh would tell you to use 1" heavy duty stainless. That's what he put in our basement but only up to the water heater. From there it is a mish mash of washer hoses, copper, and pvc.

Umm not wanting to go against your dh but pressure is going to be the same in all size lines. The only way it would drop is if you opened everything up and not enough flow could get threw.

The plastic piping your talking about would be CPVC instead of normal PVC. CPVC is made for water lines both cold and hot. The hot water will not effect the CPVC unless it gets above 180F or 100 PSI. Most home water heaters run at around 120F so it is no problem at all.
The glue will not weaken the pipe itself will fail way before the glue will as long as it is done right.
oh yea and it is made for hot water so no chemicals leeching at all will happen.
I have used it in a few thousand homes over the years without a single problem ever from it. I will even use it in my own home next time I build one.

[harrisjnet]

1/2" is plenty big enough. I have 1/2 Ht water PVC throughout my house and maintain 70 PSI.

[Danaus29]

Micahn, thanks for the corrections. He isn't here and plumbing isn't my thing that's why I said I'ld have to ask him. He might have meant when you go from smaller lines to larger openings. I wasn't real sure about the plastic either. Last time we ran plumbing all you could find in plastic was labeled "not for hot water use". That was a few years back and just what was available at Lowes.

[artificer]

Yet another vote for the 3/4" trunk lines. I would also suggest paying the extra for the thicker copper. It typically comes with two colors, blue is thicker, IIRC. Can't for the life of me remember the name/designation on the two. If your water is at all acidic, you'll be thankful years down the line when it hasn't corroded through. This is a regional problem, so may not effect your area.

Yes, they make plastic for potable water supply lines. You can even do the hot side, if you get the correct material. A better solution, if you're going with plastic, would be to get PEX tubing. This is a "home-run" system. One fixture on each line, and the other end goes to the water heater or cold supply. This is different from the traditional trunk system, where you have one main line that has the feeds for the sinks/tub/toilet going from it. With you're 42' run, the PEX may not make the most sense. If you could put a manifold in the basement, right under the bathroom area, however, it could be less expensive. I've never used PEX, so I'm not sure of the possibility of a remote manifold. Here's residential guide for PEX. Haven't look at it much, but might help.



Michael

[Micahn]

Originally Posted by artificer

Yet another vote for the 3/4" trunk lines. I would also suggest paying the extra for the thicker copper. It typically comes with two colors, blue is thicker, IIRC. Can't for the life of me remember the name/designation on the two.

A better solution, if you're going with plastic, would be to get PEX tubing. This is a "home-run" system. One fixture on each line, and the other end goes to the water heater or cold supply. .

Michael

I would say your talking about L ams M copper. The lower the letter the thicker it will be. So L is thicker then M. Most hard copper will be M and most soft will be L. But L hard is common as well.

I had bad luck with the PEX your talking about but that was about 10 years ago last time I used it. They could have improved it by now I really do not know.

[morrowsmowers]

If you use the 1/2" pipe you will have pressure but less volume. If you use the 3/4" pipe you will have the same pressure but increased volume as well. If you only have 1 bath you could cheat and use the 1/2" all the way through but with multiple baths you should run the 3/4" all the way through and just reduce in size when you make the drops to each fixture.

Also, don't skimp on shut-off valves. If something breaks later it will be easier if you can just shut off one fixture instead of the entire house.

Ken in Glassboro, NJ

[Aintlifegrand]

Originally Posted by Micahn

It is the number of fixtures not the distance.
From the sound of things this is a new home ? Remember it may cost a few bucks more to start with but over time you be glad you done it right.
Figure 3 cold water fixtures on a 1/2 line and up to 8 on a hot line. For 3 full baths I would run a 3/4 hot to at least the first one and then split it into 2 1/2 lines going to other 2.
The cold I would run a 3/4 all the way to the last bath. I am sure you have heard of someone flushing while someone is in a shower? Well be in that last bath when someone flushes in one of the others and you will be glad to have that 3/4 line lol.

So you know I was a master Plumber most of my life and took over the family company until I got hurt and can no longer work. Plus was a teacher at a plumbing apprenticeship school for many years.

So what are you doing for the next couple of weeks ...lol. The issue isn't money for supplies..the question is due to fact that some of the water supply lines are already ran and they are 1/2" copper...I wanted to make sure before I start removing the copper that I was right in thinking 3/4 Yes it is new construction and we are trying to finish the plumbing job ourselves. I want it to be right not cheap...thanks much! oh and btw the coffee is always hot or the beer is always cold at my house ...lol

[Aintlifegrand]

Originally Posted by morrowsmowers

If you use the 1/2" pipe you will have pressure but less volume. If you use the 3/4" pipe you will have the same pressure but increased volume as well. If you only have 1 bath you could cheat and use the 1/2" all the way through but with multiple baths you should run the 3/4" all the way through and just reduce in size when you make the drops to each fixture.

Also, don't skimp on shut-off valves. If something breaks later it will be easier if you can just shut off one fixture instead of the entire house.

Ken in Glassboro, NJ

Thanks so much for the reminder on the cut offs for each...I almost forgot.

[Jim S.]

I have done the 3/4" CPVC trunks last year, to 1/2" risers, replacing 1/2" galvanized.

I give it a BIG

Overall volume of delivery will be better with the 3/4. That means that if DW flushes the toilet now, I barely notice the temp change in the shower on the other side of the house.

If you are tearing out 1/2" copper, you might find it of interest to compare the inside diamter of CPVC with 1/2" copper. You have to go 3/4" CPVC to get in the same ID ballpark as 1/2" copper, and it is the ID that matters.

You will never regret 3/4" trunks to 1/2" risers. DO insulate at least the hot water line. The only drawback I have found is, even with insulation, it takes a bit longer to get hot water to the tubs and sinks on the other end of the house. I am glad I insulated.

On the glue failure, be darned sure it is done right. There are some brands of CPVC now that say they don't need a primer, but if yours needs it, use it. I had a section of CPVC already in the house that separated at a glue joint because of a poor plumbing job done before I bought the place. It makes a HUGE mess.

[Aintlifegrand]

Ok..so another question..if I am going to remove the 1/2 copper that is there and replace with 3/4...what is the best choice CPVC or Copper? If copper which type? 3/4" Type ( what) copper for instance?

[Micahn]

Originally Posted by Aintlifegrand

Ok..so another question..if I am going to remove the 1/2 copper that is there and replace with 3/4...what is the best choice CPVC or Copper? If copper which type? 3/4" Type ( what) copper for instance?

Well CPVC is a lot easier for someone who does not know a lot about plumbing to run. As long as you clean things up good with a cleaner or primer the joints should outlast the pipe itself and it will last forever lol.
Way back when I used to be very big on copper. I waited years before switching to CPVC and other types of piping for water lines (Always used PVC drains most places) because well it was still sort of new. After using it a few thousand times I would use CPVC in my own home if I was going to build one today. Not only would it be cheaper then copper but it is much less work and will last just as long if not longer.

If you use copper any type would be just fine. M copper is the most common hard copper that is installed in homes (above ground) and they use L soft copper under ground. The main reason they do not use M soft under ground is it would just be to soft to bend right and would crush to easy. But the hard M is just fine.

What ever one you use would be just fine chances are. You should check your local codes to make sure to meet them what ever you do. To bad I am so far away or I would be happy to stop by and give you any help you might need.
What ever you do make sure to pressure test it before closing up any walls or anything. Just cap every thing off and get yourself set up to pump water or air into the system. I always pumped things up to say 20 PSI looked at everything to make sure it was ok then pumped it on up to 100PSI and left it over night to make sure things was good to go. Over night a leak can leak down enough so you can see it that you might not in a short amount of time. Water makes it much easier to find the leaks but air will work just to test. You could even fill things up with water from a hose or bucket then pressure it with air I done that many times as well.
Around here the Inspectors wanted to see a pressure gauge showing it being tested so again check your local codes.

[agmantoo]

Have you done any research on Pex systems for plumbing. There are lots of advantages. Copper has lots of drawbacks IMO. You never stated the incoming pressure on the water available to your home. There are other factors that enter into a plumbing system that have not been address here.

[farminghandyman]

I was doing some study a few months ago and was comparing water flow out of an orifice, and how much pipe was needed to flow the same amount of water as a given orifice, and it really surprised me that (for example: If you have a 3/8" orifice it basically will take a 3/4" pipe to flow the same gallons as what will flow out the smaller orifice).
nozzle or orifice chart,
http://www.conservationsolutions.com...aks_nozzle.pdf
pipe, chart,
http://www.engineersedge.com/pipe_flow_capacity.htm

now on the other side of the issue, the UPC and IPC require a minimum of a 3/4" pipe main, into the house, most Hot water heaters have 3/4" fittings on them,

probably the biggest flow is out side spigots, as many fixtures restricts the flow in them now,

I would suggest that you run 3/4" as main trunk line and to each outside spigot on the house and to the toilets or near them,

depending on the way the lay out is possibly a 3/4" trunk line on hot for some of the needs,

the problem is on the hot as 3/4" holds more water than 1/2" pipe, and in that said is If you have a long run to a fixture with hot water in it, it may take a long time to get hot water to that fixture, but if you have a washing machine or a dish washer on a line and have a shower on the same line you may have a pressure drop and some major temperature or pressure changes,
(this is an item that will have to be decied on a case by case situation in my oppion)

Most have heard of plumbing situations where if some one is tanking a shower, and the a toilet is flushed the water drops off in the shower or one gets scalded, these situation is do to to small of water lines,


Water line supply charts.
http://hometips.com/articles/sunset_...pesize064.html

http://www.terrylove.com/watersize.htm

Some in my opinion is how many people in the house,
And why I make this statement, is if all you have is one or two people most of the water needs are miniminal, and the need to run two or three items at once, are not there, but if the house has 6 people in it there are more showers, more washing machine use, dish washer use, and the list goes on, so the water needs goes up and if sized to small more problems will arise, (I know codes go by fixture number, but I don't care if you have one toilet or a dozen, if you only have one person in the house you only use it so much, but if you have 12 people in the house the single toilet is used as much as a dozen units used by each, the difference is that the house by code would be plumbed differently than the one with one toilet as far as water supply lines.

~~~~~~~~~~~~~~~~

IN rural areas many times codes or inspections or permits, are not a reality,
I would at run the 3/4" on the cold side as a main trunk throughout much of the home, and branch off of it with 1/2" to most of the fixtures,

[Aintlifegrand]

Thanks for your help...

to answer the question about number of people..there are 3 living there now, but soon to be only 2...the two will use the same bathroom while the other two will be used just a couple of times a year...( yeah I know ..but it wasn't suppose to be like this...) as for the PSI from the street..it is a new rural water system that they are putting in and the water district said that it was 70psi.