New Construction Potable Water System - Sizing

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Twinpeaksr

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I am working on building a new house and have been trying to do my due dilligence to ensure I have a good design that will last as long as the house. Been browsing the forums hear for a few weeks, lots of good information! Just want to cofirm what I have learned, because I am sure it is not 100% yet.

Some Background Specs:
- System will be PEX Home Run, using Uponor ProPEX
- I will be on a shared well, 860ft deep, 5 houses on the well (will be in the well forum later, waiting on more details on the Well)
- Based on a neighbor on the same well, he has been measuring about 50psig on his line from the well, min is about 40psig, max seen is 68psig.
- Will have my own septic (will check that out at a later time) about 2000gal in size
- Well connection is about 40ft from house, will be about 80ft to first tee.
- two story house with 2.5bath, basement will be unfinished but will have a full bath down there as well. master has a shower and whirlpool tub, both full baths have dual sinks.
- will be plumbed for hydroponic radiant heat in slab, but will not be connected initially

1. Sizing of Feed - First thing I am trying to determine the proper size of the line from the well to the house. I am thinking 1". Is there a benifit to 1.25" if the first thing it goes to is a 1" connection on an iron filter (I will be finding Gary later on this)? Once in the house it will run through an Iron Filter, then Tap off to a split - 4port manifold for non-softened water (1") and connection to water softener (1"), split cold (3/4") to manifold and hot (3/4") to water heaters (2 in series, I am sure that will get some discussion) and then on to the hot manifold. It does not seem like 1.25 will gain me anything, or am I overlooking something?

2. Fixture lines - Right now I plan to use 1/2" to all fixtures, but am considering if I should use 3/4" to the whirlpool tub. The longest run is less than 50ft, any issues with this?

3. Pressure - I did a calculation using 40psig as the base and cameup with 34.4psig as a minimum (this does not include the water conditioning losses). I expect to get the same pressure from the well as the neighbor, figured the worst case he saw. Question is what is an acceptable minimum pressure to ensure things are working right? Do I need to consider boost pumps or will this be fine? I know this is considering only one fixture, but want to make sure what I am using is going to work best for the house.

Sorry for all the questions, I enjoy working with my hands, not a professional plumber (use to be an electrician) but am anxious to learn what I can.

Thanks!

~R~
 

Terry

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Water pipe sizing
This chart is good for 40-60 PSI

Does the city require plumbing permits where you live?
If so, you may want to talk to the local inspector and find which plumbing code he will be using on the inspection.
Most codes have a chart you can use.

The link above is for UPC, medium pressure.

Most fixtures if you are using the home run method get by with 1/2"
Some can use as little as 3/8", and like you mention, the tub could fill faster with 3/4" if you are using 3/4" as the filling valve.

Your distance is not very much from the pump to the home.

 

Twinpeaksr

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There are permits required, I talked to the inspector already about it, but he statement was "Most People use PEX, 1/2" to the fixtures, 3/4" everywhere else" which I did not find as useful as I had hoped as there seemed to be no real thought behind his statement more an observation. The information he provided helped with sizing the septic, but he did not provide any more info on the supply side (not sure if he just could not find the chart) I do have a call in to the well company to find out among other things their recommendations on line size from the well, but I always like multiple opinions before making a decision.

I was reading the sizing link you provided earlier, based on my estimates, looks like about 36fixtures which would be 3/4" from meter and 1" to the building. Since I don't have a meter I suspected the 1" would be fine from the well, but as stated this is for copper, and I want to make sure I am good with the PEX.

I know they tend to run slightly smaller, but it seems that the fittings are the issue more that the actual line (one of the reasons I chose the ProPEX). Not sure if that changes anything. sounds like there should be no real issues with the fixture line size especially considering the short distance (most are between 10 and 30ft.

I should clarify that the connection to the well is about 80ft to the tee, but the well pump is about 100ft further away (another thing I am checking with the well company, as well as the capacity and expansion tank size, etc...) I also do not know the size of the line from the pump to the connection I have (hope to learn tomorrow).

Thanks for the input!

~R~
 

Jimbo

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PEX changes the situation, since it has significantly smaller ID than copper or polyethylene....the preferred underground materials. It would take all day fill a whirlpool tub off a 1/2" PEX, and 3/4 is marginal for that. I would up all your numbers one size when any distance over 15' or so is involved.
 

Redwood

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You might do well to look at this link...
PEX Design Guide

I'm no fan of homeruns, my preference is trunk and branch, and in a larger home I may also go with remote manifolds for fixture groups.
That type of installation makes hot water recirculation easy.
 

hj

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Here, the inspectors do NOT use "an observation". We MUST submit a drawing of the complete water system, including sizes, along with calculations which take into account the distance from the meter to the furthest faucet, the height of the highest faucet above the meter, and the quantity of faucets.
 
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