Layout advice needed

[Chris Branscome]

My home was built in 75 and still has the original galvanized plumbing, which is starting to spring pinhole leaks, so it's time to re-plumb. I'd like to go to pex but I'm uncertain if I should install a manifold. I'll describe the layout of the house and I'd love to hear how you think I should lay out the plumbing.

The water main comes in on the northeast corner of the house, on the same wall as our kitchen. The master bath is at the southwest corner of the house, the opposite corner of the kitchen. The hot water heater is in the utility room (along with our washing machine), almost perfectly in the middle of the house, about 40 feet from where the main enters the house and about 40 feet from the master bath. There's another full bathroom about 15 feet from the hot water heater, and three outside spigots.

I'm thinking of putting a manifold in the utility room, but that would mean the main water supply would come all the way to the center of the house and then go all the way back to get to the kitchen. I'm wondering if there's any reason not to do that. Should I feed the cold tap in the kitchen, and the ice maker from branches directly off of the main trunk and then feed everything else from the cold manifold?

Thanks in advance!

 

[Reach4]

I'm thinking of putting a manifold in the utility room, but that would mean the main water supply would come all the way to the center of the house and then go all the way back to get to the kitchen. I'm wondering if there's any reason not to do that. Should I feed the cold tap in the kitchen, and the ice maker from branches directly off of the main trunk and then feed everything else from the cold manifold?

A manifold near the water heater is good if running the extra pipes is not hard. Don't worry that the kitchen cold takes a longer than needed trip except that it may warm up during the trip.

Consider getting the hot to the lavatory run in 3/8 PEX. Because it holds less water, it will let that water warm up sooner after you open the faucet. I am not a plumber.

 

[Sponsor]

 

[Terry]

There are so many ways to run water in an older home. So much depends on your access. Generally, you will need 1/2" on the hot for each bathroom and 3/4" on the cold because you have the added need for the toilet when it's being flushed.
If you run one line for two bathrooms, you will need 3/4" for the hot before you split it down. You can get by with 3/8" if it's only supplying one fixture.

 

[Chris Branscome]

I probably should have included a diagram before, so here it is now. Here are the questions I have. These questions only apply if using a manifold is okay for this layout. If I shouldn't use a manifold, please tell me.

1) From the manifold, should I have one output per room, or one per fixture?
2) What diameters would you use for the main supply and the outputs?
3) The main water supply comes up out of the ground in the driveway, terminating in a T. Is there any reason not to keep it like that?

 

[Reach4]

) From the manifold, should I have one output per room, or one per fixture?

What your diagram proposes looks good. When people talk about a manifold system, they usually mean one output per fixture. So even though you are using a manifold, it is not quite what people picture when you use the term manifold system.

2) What diameters would you use for the main supply and the outputs?

Terry addressed the fixtures in #3. You probably want to up the supply to the utility room to 1 inch.

3) The main water supply comes up out of the ground in the driveway, terminating in a T. Is there any reason not to keep it like that?

No. Even though I am not sure what you are describing. I was thinking you meant branching through a tee.

While you are thinking about it, consider leaving provision for a water softener or other water treatment. The spigots used for lawn watering should not be fed by a softener.

 

[Chris Branscome]

No. Even though I am not sure what you are describing. I was thinking you meant branching through a tee.

Oops - on two counts. First, I failed to complete the description of the supply...

It comes up out of the driveway, to a T. One branch of the T goes into the house through the exterior wall, and the other branch terminates in an outdoor spigot.

The other oops is that in the diagram I show two toilets in the master bath (the bathroom at the top). The top right "toilet" in the master bath is actually a shower - meaning that bathroom has a tub and a separate shower.