What size is my curb box likely to be?

[Pipehitters local 420]

Hi there,

I own an old house that was piped with a half inch water supply. I'm in the process of redoing all the piping systems in the house and I am interested in upgrading the underground service to new 3/4. When I called the city to ask questions I was basically told to forget about it and that they would have to dig up the street and I'd be looking at 12,000 to 20,000 dollars.

If that's the case I wont pursue it any further but I'm wondering if maybe the street doesn't need to be dug up. I'm wondering if back in the good old days they could've piped to the curb box in 3/4 or bigger and then bushed down to 1/2". That would just make sense to me in case somebody like me wanted to upgrade the service one day. Anyone know what I can expect with regard to this?

 

[Reach4]

Don't assume that upsizing the piping after the curb box is not worthwhile, although if doing that, I would run at least 1 inch thru the yard. Difference in cost is not that much.

Pressure drops in pipes add. So even if there is 1/2 inch pipe for 30 ft, upsizing the rest of the way to the house is good. It's not like auto traffic where the pinch point determines how many cars per hour can pass.

I don't know the answer to your title question.

 

[Sponsor]

 

[Breplum]

Generally speaking, unless someone is adding fire sprinklers or tons of new bathrooms, the size of the supply to the meter is not a factor.
What Reach4 says is that pressure drop over distance affects flow. Size your main to match the number of fixtures.

 

[Terry]

A two bath home gets a 1" water service from the meter, even if its a 5/8" meter.

 

[Pipehitters local 420]

Don't assume that upsizing the piping after the curb box is not worthwhile, although if doing that, I would run at least 1 inch thru the yard. Difference in cost is not that much.

Pressure drops in pipes add. So even if there is 1/2 inch pipe for 30 ft, upsizing the rest of the way to the house is good. It's not like auto traffic where the pinch point determines how many cars per hour can pass.

I don't know the answer to your title question.

Maybe my understanding of pressure/flow rate/resistance is wrong then. Assuming cars per hour is equivalent to gallons per minute you've completely lost me.

I will definitely go 1" to the meter though. 3/4 for the main's after the meter. thank you for that. Hopefully there's a noticeable difference as a result of this.

 

[Terry]

It's about friction loss. Think of using a small straw on a milk shake. The bigger straw is a lot easier to use.

 

[Reach4]

Maybe my understanding of pressure/flow rate/resistance is wrong then. Assuming cars per hour is equivalent to gallons per minute you've completely lost me.

Not equivalent. Analogous.

Would an electronics comparison to resistors be better?

Not that it matters. It is good you are up-sizing the pipe.

 

[Jeff H Young]

So Im assuming your curb box just holds the curb cock and a meter is below your house in basement? so yea why not run correct size pipe from your box whether its undersize from street to curb box or not. you still pipe what you can correctly .
why its 1/2 I dont know but thats what it is. whether from box to main in street is 3/4 ? or anysize 1/2" or 1" i can only guess

 

[Pipehitters local 420]

So Im assuming your curb box just holds the curb cock and a meter is below your house in basement? so yea why not run correct size pipe from your box whether its undersize from street to curb box or not. you still pipe what you can correctly .
why its 1/2 I dont know but thats what it is. whether from box to main in street is 3/4 ? or anysize 1/2" or 1" i can only guess

Maybe I'm wrong in calling it the curb box or service box. But yes the curb cock or shutoff valve is on the boulevard. The water meter is in the basement. This past summer I had contractors dig a section of slab up to change the old cast iron drainage and add a backflow. I had them throw some tubing in before they patched the concrete back up. This tubing was just for the future. It dead ends at the edge of the house and at the meter. I originally asked for 1 1/4 pex but they told me I didn't need it. Then I asked for 1" copper and didn't get that either. They ended up giving me 3/4 copper just to keep me happy. It was like pulling teeth.

I am and will be upgrading everything I possibly can inside my house. That's not the issue.

I guess what I am asking is what people have seen with regard to curb cocks. Is a water service upgrade ever done at the valve? or is it always done on the main at the street? Is it almost always one size in, same size out like in this picture?

Its an old house built just after the second world war. I have a visualization in my head of a mechanical tee with 1" threaded galvanized running to the curb cock and then adapting to 1/2 copper tubing. Am I crazy to think that?

 

[Jeff H Young]

ok local 420! Ok what I or you expect in size3 doesn't matter I'd run one inch to that 3/4 copper your plumber put in ground.
It is what it is I'm guessing 1/2 3/4 or 1" you said from box to house is 1/2 " so that doesn't make me expect that from the main to the box is 1 inch or any particular size
\

 

[hj]

About the cars versus water through a pinch point. IF the cars could go faster thru it then the comparison would be valid. I doubt that your main line valve is smaller than 3/4".

 

[Reach4]

About the cars versus water through a pinch point. IF the cars could go faster thru it then the comparison would be valid. I doubt that your main line valve is smaller than 3/4".

Not to overstretch the analogy, but what if that pinch point was the famous section of Lombard Street in San Francisco? Things could get turbulent.

So I was thinking of putting sections of road in series, but the actual road piece would be a black box with certain resistance vs car flow.

But the traffic analogy was to name a relatable model that water does not follow. People often have the idea that the flow is governed by the smallest pipe, so no sense increasing size beyond that minimum. So with the road flow analogy I was trying to compare to a system where the smallest path determined the thruput.

My favorite analogy would be resistors in series, but that does not resonate with many. That is a

 

[Jeff H Young]

Not to overstretch the analogy, but what if that pinch point was the famous section of Lombard Street in San Francisco? Things could get turbulent.

So I was thinking of putting sections of road in series, but the actual road piece would be a black box with certain resistance vs car flow.

But the traffic analogy was to name a relatable model that water does not follow. People often have the idea that the flow is governed by the smallest pipe, so no sense increasing size beyond that minimum. So with the road flow analogy I was trying to compare to a system where the smallest path determined the thruput.

My favorite analogy would be resistors in series, but that does not resonate with many. That is a

I get Reach 4 example. I think the point is if you are replacing a section of old pipe and you cant replace it under street is to run proper size pipe from curb box and not to run a 1/2 inch just because thats what one section is.

 

[Pipehitters local 420]

About the cars versus water through a pinch point. IF the cars could go faster thru it then the comparison would be valid. I doubt that your main line valve is smaller than 3/4".

This is more along the lines of what I've been hoping to hear. It's now worth digging things up to have a look. Thank you for all the responses gentlemen.