Repiping advice

Users who are viewing this thread

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
Hello all, I am going to be doing a complete repipe on my small 1920's house.
1 bath, kitchen and laundry, all accessible from the basement.
Currently all supply lines are 1/2 galvanized and I want to switch to copper, (no I don't want pex) getting lots of black flakes in my water from time to time. I remodeled the kitchen last summer and installed copper in the wall so that part is done. The pipe that was there was being insulated by newspapers dated 1929! The bathroom is slated for a re-do so any pipe I can't change now would be done then.

My question is this, you all seem to down on the 'trunk and branch' system, so I'm wondering why that is and what would be a better system?
I was thinking of just replacing what I have, the only change i would make is ball valves and 3/4 main line instead of the 1/2.

Any suggestions or am I on the right track?

Water pipe sizing
 
Last edited by a moderator:

Basement_Lurker

One who lurks
Messages
664
Reaction score
1
Points
0
Location
Victoria, BC
95% or more of homes are built with the branch and trunk system, which is totally fine so long as it is sized properly. A small home like yours will be fine with a 3/4" service and trunks.
 

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
Thank you!
So, 3/4 from the street, change to 1/2 at the main shut off and the rest of the house done in 1/2 would be fine then.
That is good news as I couldn't really think of a better way to run the lines than what is already there.

Water pipe sizing
 
Last edited by a moderator:

Gary Swart

In the Trades
Messages
8,101
Reaction score
84
Points
48
Location
Yakima, WA
I will defer most of you question to real plumbers, but just point out that while 3/4" will carry a lot of water, unless you install a recirculating system, any fixture using hot water that is any distance from the tank, will require a great deal of time and water wasted while the cold water in the line is purged. When I repiped my house years back, I used 3/4" for the hot water to my bathroom. It was so annoying that I replaced the 3/4" with 1/2". Later I added a recirculating system, so the 3/4" would have be OK if I hadn't replaced it. Fortunately, all of my pipes are in the basement so no serious difficulty in the doing this.
 

hj

Master Plumber
Messages
33,602
Reaction score
1,041
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
quote; 3/4 from the street, change to 1/2 at the main shut off and the rest of the house done in 1/2 would be fine then.

And WHO said that? A complete system in 1/2" pipe, even if it is copper, will NOT be fine.
 

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
quote; 3/4 from the street, change to 1/2 at the main shut off and the rest of the house done in 1/2 would be fine then.

And WHO said that? A complete system in 1/2" pipe, even if it is copper, will NOT be fine.

I said that and I currently have the entire system in 1/2 galv, so it WILL be fine as it HAS been fine since 1923.
In fact it's 1/2 galv from the street now, I'm planning on bringing 3/4 into the house from the street, then dropping to 1/2 throught the house as it currently is.

I know from reading your posts that YOU think only REAL plumbers can make water flow but I think I can take my chances.

If there is a genuine reason why my current system isn't 'fine' then please let me know but as I have lived here for 15 years with NO problems I can not see what it may be.
Thanks

Water pipe sizing
 
Last edited by a moderator:

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
I will defer most of you question to real plumbers, but just point out that while 3/4" will carry a lot of water, unless you install a recirculating system, any fixture using hot water that is any distance from the tank, will require a great deal of time and water wasted while the cold water in the line is purged. When I repiped my house years back, I used 3/4" for the hot water to my bathroom. It was so annoying that I replaced the 3/4" with 1/2". Later I added a recirculating system, so the 3/4" would have be OK if I hadn't replaced it. Fortunately, all of my pipes are in the basement so no serious difficulty in the doing this.

Thanks for the reply, I guess maybe I wasn't clear, the entire house will be 1/2, after stepping down from 3/4 at the shut off in the house. From the street to the house will be 3/4.

Water pipe sizing
 
Last edited by a moderator:

Basement_Lurker

One who lurks
Messages
664
Reaction score
1
Points
0
Location
Victoria, BC
A small home like yours will be fine with a 3/4" service and trunks.

1/2" trunks are undersized these days. A small home like yours with only 1 bath and kitchen is probably fine with 1/2" copper, but if you are going to all the trouble, it's best to do it with 3/4" service AND TRUNKS!
 

Terry

The Plumbing Wizard
Staff member
Messages
29,942
Reaction score
3,459
Points
113
Location
Bothell, Washington
Website
terrylove.com
A standard one-bath home with kitchen sink, dishwasher, water heater, clothes-washer, 1.6 tank toilet, lavatory, tub/shower combo and two hose bibs would be counted as 18 fixture units

At 80 feet, you can run 3/4" for up to 19 fixtures. If you ever add a second bath, the 3/4" will be undersized.

If you ever plan on adding a second bath, I would run 1" from the meter.

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.

In Seattle, if you have a tub, lav and toilet, the cold will require 3/4" for the 7.5 fixture units there.
The tub faucet will need to be pressure balanced.
 
Last edited:

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
A standard one-bath home with kitchen sink, dishwasher, water heater, clothes-washer, 1.6 tank toilet, lavatory, tub/shower combo and two hose bibs would be counted as 18 fixture units

At 80 feet, you can run 3/4" for up to 19 fixtures. If you ever add a second bath, the 3/4" will be undersized.

If you ever plan on adding a second bath, I would run 1" from the meter.

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.

In Seattle, if you have a tub, lav and toilet, the cold will require 3/4" for the 7.5 fixture units there.
The tub faucet will need to be pressure balanced.

Thanks!
No plans and no room to add anything. 1 bed room, 1 bath, 1 person.
As of right now you have discribed my house perfectly, exept I have an older water guzzling toilet and I estimate 70 feet from the meter at the street.
So 3/4 from the street, 1/2 the rest of the way will do?
I'm in Pierce county, Sumner just South of seattle.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,942
Reaction score
3,459
Points
113
Location
Bothell, Washington
Website
terrylove.com
You have to count backwards from the farthest plumbing fixture.
If you have a bathroom at the end, you would need 3/4" until you break off between the three fixtures for the cold.
If your kitchen is farther then your bathroom, you will need 3/4" on the hot until you pull off the kitchen.
Look at the chart, and work backwards. You are going to be using more 3/4" then what you had before. What they did in 1928 is not what is being done eighty years later. Times change.
The entire state of Washington is working under the same code.
 

Gary Swart

In the Trades
Messages
8,101
Reaction score
84
Points
48
Location
Yakima, WA
I'm going to take a bit of exception to the real pros on this issue. It seems to me that while pipe sizing using fixture units is perfectly correct where several people will be using water in different places all at the same time, with one or even two people in a small home such as yours, it is highly unlikely that the shower, dishwasher, clothes washer, kitchen sink, and toilet will all be in use at the same time. Now, a three or four bedroom home with 4 teenagers, wife, and husband all getting ready for school or work at the same, using 2 or 3 bathrooms would be different. I think you will be fine with 1/2" as you describe. The only exception I would make is for the difference in the cost of material, I would consider a 1" supply from the street. That may be overkill, but think about it. Again, I'm not saying the pros are wrong, but as professionals they have look at these things from the codes they have to follow. As I noted in my first post, I removed my 3/4" hot water line and replaced with 1/2" because of the time it took to purge the cold water from the line and the water that was being wasted. I saw no difference in flow with the change, and even when my wife and I are using different fixtures at the same time, there is no noticeable change in the flow. You really should get a new Toto to replace the old water hog, but that's a whole "nuther" story.
 

Storm rider

Slave to rentals
Messages
112
Reaction score
28
Points
28
Location
Nevada
The $100 you save today by using smaller pipe (you are doing all the work anyway) will come back to bite you when you sell the house. Some home inspector will note that the piping "appears to be undersized", and the buyer will want a $2500 reduction in the price of the house.
 

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
You have to count backwards from the farthest plumbing fixture.
If you have a bathroom at the end, you would need 3/4" until you break off between the three fixtures for the cold.
If your kitchen is farther then your bathroom, you will need 3/4" on the hot until you pull off the kitchen.
Look at the chart, and work backwards. You are going to be using more 3/4" then what you had before. What they did in 1928 is not what is being done eighty years later. Times change.
The entire state of Washington is working under the same code.

Am I counting back from the shut off? Because it's in the center, the kitchen is on one side of the house and the bath on the other, with the main entering right in between.
Looks like you are saying I need to bring 3/4 in then run it to the WH and kitchen and to the bath, reducing to 1/2 as I run to each tap?
 

Drivesme

New Member
Messages
33
Reaction score
0
Points
0
Location
Washington state
Thanks all for the answers! You do a great service here!
My next question is because a friend is really pushing me to use Pex, which I'm not too impressed with but, price wise it would make things much easier.
Would the pipe size remain the same?
Which brand is best? I know pex A is best but does brand matter?
Which connection method is best?
Thanks!
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks