Moving water supply line

[Zenman]

I need to move the water supply line due to a 1st floor bath room layout change. So the first 20-30 feet of copper after the meter needs to be relocated. The supply is all copper, and this is a 1950's cape with 2 1/2 baths.

What I need help with is calculating whether or not I need to up-size the copper supply after the meter (to meet todays standards\codes). From the street to the meter is 3/4" and its the same for the main branch. Individual fixtures are all 1/2". I have not noticed any water pressure issue as is, BUT since I am moving the first 20 to 30 feet of copper right after the meter would it be wise to replace this section with it something larger?

Please see attached image and let me know if more information is needed. Thanks!

 

[Terry]

Water pipe sizing​

Even though the meter is 3/4", I would upsize from the meter to 1" pipe until you have 17 fixture units left, at which point, you can drop down to 3/4" and eventually when you get down to six fixture units, you can drop to 1/2"​

Most standard two bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, two 1.6 tank toilet, two lavatories, one shower, one tub/shower combo, and two hose bibs would be counted as 23.5 fixture units.

Most standard three bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, three 1.6 tank toilet, four lavatories, two showers, one tub/shower combo, one whirlpool bath and two hose bibs would be counted as 34 fixture units.

 

[Sponsor]

 

[Zenman]

Great, thanks Terry, thats exactly what I was looking for!

 

[NHmaster]

Was that drawn with google sketchup?

 

[Zenman]

Was that drawn with google sketchup?

Ha! (or should I say LOL!) No, I did it in Microsoft Paint. I havent had a chance to play with Google Sketchup. I downloaded and installed it a year or two ago. I tried to use it once, but didnt have time to figure it out. In this case Microsoft Paint was much faster for me to draw in.

 

[hj]

pipe

This is a single family residence, so it is unlikely you would ever have a situation where the demand is greater than what 3/4" will supply, regardless of how you relocate the pipe. I would use 3/4" if I were doing it.

 

[Zenman]

Thanks for your input. Yes a residential home, with no water supply problems as is. I just need to move the supply line over one joist bay because it is in the way of the new bathroom drain pipes (3 inch PVC). So I figured if I needed to move it this would be the best time to up-size it - but only if it was needed.

I priced the copper and its not cheap, the 1" is a lot more expensive than the 3/4". And with the 3/4" I could possibly reuse some of the old pipe. However price would not be the determining factor.

Hmm what to do... at least now I have some math (Terry's chart) behind my decision. However practically speaking, if it aint broke, dont fix it!

 

[hj]

math

Math is good, IF you have a house that uses water like the mathematician calculated. That means you would have to be using HIS calculated amount of water from as many faucets as it would take to do it.

 

[Terry]

That chart is taken right out of the UPC plumbing code book.
It's how we have to size water in Washington State.
It's not the "recommended" sizing, it's the minimum sizing allowed.


Arizona may be different.