Water Supply Units calculation correct? Maximum wsfu seems low for 3/4"

[Gslenk]

I am in the process of planning a basement remodel. I am unsure what was/wasn't done with permits/code and looking for help on the feasibility of my project meeting code.

TL/DR: 2015 IPC, Existing 14.2 WSFU demand (plus 2 hose bibs?). Planned 17.8 (+2 hose bibs) wsfu demand. 3/4" supply into basement main valve, 3/4" main distribution branch almost the full length of just under 50ft inside the house. House is ~30ft from the street with no access holes for outside main valve in sight. 2 floors, 3br/2ba. Kitchen/laundry. Want to add a full basement bathroom. Code books seems to indicate 3/4" is too small even for existing. I will assume 50 psi water pressure until I measure it ( I think a read somewhere 50+ is standard for my area). So Questions...
#1: Did I screw up, if so on what?
#2: If this is not sufficient for existing and/or adding a bathroom, will 1" Distribution pipe cover existing and/or planned demand, realistically and according to code?
#3: Where does "Distribution pipe" start and end? I think I read it starts at the inside water main valve, I assume it ends at the ends at the furthest fixture. I am willing to up the pipe from there, but if I have to dig out to the street/front yard, I will abandon this dream, for now.

More details:

My area uses 2015 IPC. Here is what my house has:
Master bath group:
1 Shower
1 Water Closet (1.28 gpf)
1 Lavatory
Main floor bath group:
1 Bathtub/shower
1 Water Closet (1.28 gpf)
1 Lavatory
Kitchen:
Sink + Dishwasher
Laundry:
1 "Laundry Tray" (utility sink)
1 Washing Machine
Other:
1 Wet bar sink (I assume this is similar to kitchen sink, unless a Lavatory counts, for now)
**2 hose bibs (outside) Not supplying anything "constantly", not sure what value to use.
+Addition plan:
1 Basement bathroom group

Water Supply Calculations
According to table 103.3(2) I get this (wsfu) total: 14.2+ (17.8+ after adding another bathroom)
Master Bath (3.6) + Main floor bath (3.6) + Kitchen sink/DW (2.8) + Laundry washer+sink (2.8) + wet bar sink (1.4)
With adding a full bathroom group to the basement, add 3.6 for a new total of 17.8 wsfu.

According to (all pressures) Table E201.1 indicates, "3/4 inch Meter and Service Pipe" with "3/4 inch Distribution Pipe" The maximum wsfu is 9.2 for 3/4", 3/4" pipe. This seems absurdly low for 3/4" pipe. My parents house has a similar number of fixtures, MUCH more (longer) pipe (same 3/4") and supplies more than my house existing does. Their house has one less bathtub than I plan to have after the remodel. No problems in that house when it was packed with MANY people.

Using 3/4" Service pipe and 1" Distribution pipe jumps up dramatically to 32 WSFE @ 80ft length, and 18 wsfu up to 150 ft developed length (generous margin here).

Using Terry's posted tables here I have:
Existing wsfu: 27 (3/4 x 3/4 not sufficient)
Planned wsfu: 34.5 (3/4 x 1 marginally sufficient if equivalent total length is under 80ft, its close, 3/4 x 1.25 very sufficient)

 

[Terry]

The smallest I would ever go is 1"
Going to 1.25" doesn't hurt you. It's less friction loss. I would never install 3/4" pipe to a home with more than one bathroom.

 

[Sponsor]

 

[Gslenk]

Where would that 1" start? Interior main valve, or the valve that is hiding in my font yard/street/etc? You charts indicate the outside valve, others I have found online indicate the main valve in the house, and the code-book is evading my searches so far.

My predicament is in order to add a legitimate bathroom (in the event of resale, etc...) I need permits, which need an inspection. And if this inspector counts my WSFU's (or checks my plans) he may say, you need XXX size pipe, and it will either be there, or not. I am hoping to plan for the "it is right here" situation. Of course it also has to work correctly, but the current setup works fine. Cost/benefit while the basement is apart leads me to 1" anyway, but not meeting codes negates any incentive to make an addition requiring a change.

 

[Terry]

Every foot you add in length adds to the friction loss.
I've installed a lot of 1" poly lines that were about 80 feet long. They were like a fire hose at the end. Then I replaced a line that was 330 feet long, and the water out of the end came out slowly.
The place next door had a copper 3/4" line that was 250 feet long. It worked fine for the home use, you get used to it. When I added an irrigation system to that, the heads wouldn't pop up. I changed the line to 1-1/2" and everything worked great. The 3/4" meter at the street was never changed.

 

[Gslenk]

That sounds like the 1"+ was done only from inside the house? If so those examples provide some motivation to up size, regardless of my decision to add a bathroom.

2015 IPC has these definitions:
Water Distribution pipe: A pipe within the structure or on the premises that conveys water from the water service pipe, o̶r̶ ̶f̶r̶o̶m̶ ̶t̶h̶e̶ ̶m̶e̶t̶e̶r̶ ̶w̶h̶e̶n̶ ̶t̶h̶e̶ ̶m̶e̶t̶e̶r̶ ̶i̶s̶ ̶a̶t̶ ̶t̶h̶e̶ ̶s̶t̶r̶u̶c̶t̶u̶r̶e̶, ̶t̶o̶ ̶t̶h̶e̶ ̶p̶o̶i̶n̶t̶s̶ ̶o̶f̶ ̶u̶t̶i̶l̶i̶z̶a̶t̶i̶o̶n̶.̶
Water service pipe: The pipe from the water main or other source of potable water supply, or from the meter when the meter is at the public right of way, to the water distribution system of the building served.

I need to locate my meter to be 100% sure, but its not on/near my exterior wall, so it must be at the public right of way as the only other option (and not "at the structure"). It enters at the basement directly, to the main shutoff valve inside. This sounds like the "distribution system of the building served".

So...
1) Does my interpretation sound correct: The "water distribution pipe" (pipe that potentially needs to upsize to 1"+) starts at the main shutoff immediately inside the building?

And 2) Where should the 1"+ portion end? It appears to me at the tee where cold water splits to the water heater (black circle), at the minimum (easy/simple), and possibly at some point after at least one bathroom group (black square, a little more effort).

Attached is the existing layout, thick lines are 3/4" type L copper, thin lines are 1/2". Measurements err generously on the "longer than actual" side. Vertical lines are vertical, diagonals are horizontal.

 

[Gslenk]

https://terrylove.com/forums/index.php?threads/fixture-unit-values-pipe-sizing-for-remodel.71391/

This thread seems to confirm that I can start the 1" or 1.25" at the main valve just inside the house. Can anyone confirm this?