1/2” copper from street

bignozzle

I bought a 2 bed 2 bath mobile home and it has 1/2” copper supply from the city water supply. This seems a little small, but I thought someone might have first hand knowledge of how this would work. Thanks I’m advance.

ChrisJ

bignozzle said:

I bought a 2 bed 2 bath mobile home and it has 1/2” copper supply from the city water supply. This seems a little small, but I thought someone might have first hand knowledge of how this would work. Thanks I’m advance.

I would think it would work fairly poorly and likely isn't allowed by code.
Even the galvanized pipe I pulled out of my house from the 40s or 50s was 3/4" originally.

Now days most water companies run 1" because of the wide spread use of polyethylene but 3/4" copper or galvanized was the standard for a long long time.

1/2" copper will work, just less than spectacular. Are you 100% sure it's 1/2 to the curb stop? I don't think they even make a 1/2" curb stop.

EBEBRATT-Ed

I have seen 1/2" in older houses. It will likely be fine if you have decent water pressure

hot_rod

How long is the run and what pressure do you have at the home?

unless it is hundreds of feet long, you will probably have plenty of flow to run showers, etc. If not you can get pressure booster pumps  to get you more capacity

bignozzle

It’s 1/2” at the meter which is about 10’ from the street. Oh well It’s been in use for 50 years. There’s no working plumbing so I won’t know for a while how it’s going to work.

ChrisJ

bignozzle said:

It’s 1/2” at the meter which is about 10’ from the street. Oh well It’s been in use for 50 years. There’s no working plumbing so I won’t know for a while how it’s going to work.

Where is the meter and how hard is it to change?

What size is it before the meter?

Jamie Hall

Unless your street water pressure is really sick, 10 feet of half inch isn't going to be a problem at all.

ChrisJ

This forum is incredible sometimes.

90% of the time it's all (We need to go above and beyond code! Code is the bare minimum!)

Other times its a 1/2" line supplying a place with two bathrooms is just fine.

Larry Weingarten

Hi, @bignozzle , It looks like you can get about 7 gpm out of a ten foot 1/2" copper pipe with a 10 psi pressure loss. So, what it the maximum likely water draw?

Yours, Larry

jumper

Jamie Hall said:

Unless your street water pressure is really sick, 10 feet of half inch isn't going to be a problem at all.

Some plumbers tell me that too big service makes plumbing noisy. I know a homeowner who paid for over sized service and his plumbing is noisy. Don't know if that is reason.

ChrisJ

jumper said:

Jamie Hall said:

Unless your street water pressure is really sick, 10 feet of half inch isn't going to be a problem at all.

Some plumbers tell me that too big service makes plumbing noisy. I know a homeowner who paid for over sized service and his plumbing is noisy. Don't know if that is reason.

hot_rod

Larry Weingarten said:

Hi, @bignozzle , It looks like you can get about 7 gpm out of a ten foot 1/2" copper pipe with a 10 psi pressure loss. So, what it the maximum likely water draw? Yours, Larry

7.5- 10 psi is the range of acceptable pressure drop that engineers use. It’s probably 5/8. Considered 1/2” copper in plumbing speak.
Most water meters are 5/8”

The number to be concerned with might be velocity, as that could erode the tube if it is excessive. Below 8 fps is acceptable in cold water piping. At 7 gpm you would’ve around 6.5 fps

ChrisJ

hot_rod said:

Larry Weingarten said:

Hi, @bignozzle , It looks like you can get about 7 gpm out of a ten foot 1/2" copper pipe with a 10 psi pressure loss. So, what it the maximum likely water draw?

Yours, Larry

7.5- 10 psi is the range of acceptable pressure drop that engineers use. It’s probably 5/8. Considered 1/2” copper in plumbing speak.
Most water meters are 5/8”

The number to be concerned with might be velocity, as that could erode the tube if it is excessive. Below 8 fps is acceptable in cold water piping. At 7 gpm you would’ve around 6.5 fps

Most residential water meters are 5/8 ID with 1" NPS connections connected to a 3/4" ID water service. The fixtures for these meters are typically 3/4" ID.

bignozzle

I’ve decided to run 3/4 off of the 1/2” existing main, and then branch off the 3/4 with 1/2 to the fixtures. If it works fine if not I’ll dig up and put in 3/4. As far as oversizing pipes, I replaced a 3/4” main with 1” going into a duplex. Didn’t notice any difference in pressure or noise.
thank you for all the help

ChrisJ

bignozzle said:

I’ve decided to run 3/4 off of the 1/2” existing main, and then branch off the 3/4 with 1/2 to the fixtures. If it works fine if not I’ll dig up and put in 3/4. As far as oversizing pipes, I replaced a 3/4” main with 1” going into a duplex. Didn’t notice any difference in pressure or noise.
thank you for all the help

I'm sure it's going to work.
It's a question of how much you or others will be annoyed by it. I lived with a grossly restricted 3/4" galvanized service for 9 years. It worked, but was annoying if you wanted to fill the pool and take a shower, or flush a toilet while taking a shower etc. But it got the job done. And that was with 85-90 PSI coming in at the street. It dropped to 30 PSI if you flushed a toilet.