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# Thread: Connect Water Meter Pigtail To New Poly (PE) Water Line

1. 10 feet elevation causes a 4.33 PSI drop. Add to that any frictional losses due to the water flowing. If you are measuring 52 PSI at the house while you are not using significant water, the pressure at the meter is a lost less than 70 PSI, or the elevation change is a lot more than 10 ft.

Once the supply pipe is filled, as much water comes out of it at the house as goes into it at the meter for all practical purposes.

2. Originally Posted by Reach4
If you are measuring 52 PSI at the house while you are not using significant water, the pressure at the meter is a lost less than 70 PSI, or the elevation change is a lot more than 10 ft.

Once the supply pipe is filled, as much water comes out of it at the house as goes into it at the meter for all practical purposes.
I'll be measuring the PSI with a gauge tomorrow. I called the local water utility company and they looked in their computer system and told me my meter produces 52 PSI. I know I shouldn't take their word for it, but they are probably close to actual PSI. My point was: If pressure is strong at the meter, say 70 PSI, than I'm thinking the meter will be able to replace water in a 1 1/4" line much easier when water comes out of the line at the house as opposed to a meter producing 52 PSI. Does that make sense? I'm concerned my pressure might be too low at the meter for a 1 1/4" line with a 10' gain in elevation. Maybe I'm making this too complicated in my own mind.

3. Originally Posted by AlexS
I'll be measuring the PSI with a gauge tomorrow. I called the local water utility company and they looked in their computer system and told me my meter produces 52 PSI. I know I shouldn't take their word for it, but they are probably close to actual PSI. My point was: If pressure is strong at the meter, say 70 PSI, than I'm thinking the meter will be able to replace water in a 1 1/4" line much easier when water comes out of the line at the house as opposed to a meter producing 52 PSI.
Yes. If the meter pressure was lower, that would be a reason to use bigger pipe.

Originally Posted by AlexS
Does that make sense? I'm concerned my pressure might be too low at the meter for a 1 1/4" line with a 10' gain in elevation. Maybe I'm making this too complicated in my own mind.
I presume at this point, an doubts would be about whether you need something larger than 1-1/4. Terry said "With 300 feet, you would be better off using 1-1/4" Poly ". That's a good indication that 1-1/4 would be up to the job.

http://www.engineeringtoolbox.com/pe...oss-d_619.html may be of use to you.
Now how much pressure drop would be too much? Remember you are going to lose 4.33 PSI due to the rise. Losing another 10 PSI during max water use would seem to me to be not so bad. You would be using about 22 GPM at that point if I read that right.

4. I presume at this point, an doubts would be about whether you need something larger than 1-1/4. Terry said "With 300 feet, you would be better off using 1-1/4" Poly ". That's a good indication that 1-1/4 would be up to the job.
I do recall Terry said 1 1/4". I'm taking all the risk and I want to be sure.

http://www.engineeringtoolbox.com/pe...oss-d_619.html may be of use to you.
Now how much pressure drop would be too much? Remember you are going to lose 4.33 PSI due to the rise. Losing another 10 PSI during max water use would seem to me to be not so bad. So if your water pressure dropped to 35 PSI, that would not be ideal, but not terrible in my opinion. You would be using a lot of water at that point.
In summary, a 1 1/4" pipe would mitigate the pressure drop due to a 10' elevation gain and 300' of friction better than a 1" pipe considering 52 PSI from the meter? I looked at the engineeringtoolbox link, but I don't know how to use the charts. Thanks for sending it.

Also, I'm not considering 1 1/2".

5. Originally Posted by AlexS
In summary, a 1 1/4" pipe would mitigate the pressure drop due to a 10' elevation gain and 300' of friction better than a 1" pipe considering 52 PSI from the meter?
Yes. I am shocked that you are asking that question.
Originally Posted by AlexS
I looked at the engineeringtoolbox link, but I don't know how to use the charts. Thanks for sending it.

Also, I'm not considering 1 1/2".
Please do not think that 1 inch would be a performance improvement over 1-1/4 in any way.

6. Originally Posted by Reach4
Yes. I am shocked that you are asking that question. Please do not think that 1 inch would be a performance improvement over 1-1/4 in any way.
I consider calculating pipe size the hardest part, not the actual work. I really appreciate all your posts Reach. I'm going with 1/1/4". I already have a 300' roll of 1 1/4". I bought 200 PSI CTS. Did I make a mistake? Should I have purchased IPS? I think the inside dimensions are the same, but the walls are a little thicker on the IPS.

7. Originally Posted by AlexS
I consider calculating pipe size the hardest part, not the actual work. I really appreciate all your posts Reach. I'm going with 1/1/4". I already have a 300' roll of 1 1/4". I bought 200 PSI CTS. Did I make a mistake? Should I have purchased IPS? I think the inside dimensions are the same, but the walls are a little thicker on the IPS.
You have it backwards, but it doesn't matter. You have the 1-1/4 CTS poly, so use it in good health. You WILL purchase waterworks compression fittings for it, that include the stainless-steel internal stiffener, as there is no other usable choice available. (insert fittings are definitely not sized for CTS poly tubing)

8. It looks like 1-1/4" CTS has a 1.05" Inside diameter.

So the chart below for 300 feet, more closely would be for the 3/4" meter, and 1" pipe.

In the 70's I run 350 feet with 1" poly and was a bit stunned to see how little water came out the end.
I was used to hooking for water services between 40 and 80 feet, where the water would just shoot out the end of the pipe like a fire hose.
The 350 foot line was running at 72 PSI and there wasn't much there at the end. Friction does take it's toll.

That's the last time I ever even considered using 1" for that distance.
The house next door, years later when that was replaced, we went with 1.5" PVC.

9. Thank you all. Trenching was the hardest part, not calculating proper pipe size as I said earlier.

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