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Saturday, October 13th 2012, 11:52pm

1.5" service line and meter

I have a 1.5" water meter and 1.5" service line with 65 PSI static
pressure. All of the tutorials that I see (I've read several including
from Hunter and Orbit) only include up to 1" or maybe 1.25" in their
charts. Any suggestions on how I should adjust the numbers for the
larger pipe?

This is for an unlandscaped backyard. The home builder has some zones in the front yard with 12 Hunter PGPs, so it looks like I have some good capacity. Just want to be able to quantify it.


Supreme Member

Posts: 5,298

Location: Metro NYC


Sunday, October 14th 2012, 10:56am

Why not use the existing system as a guide? You should be extending that system, with more zones, as opposed to starting completely anew.


Sunday, October 14th 2012, 3:25pm

Maybe I am overthinking this. I guess I just don't know how to use the existing system as a guide- it was a bank owned house so I have no contact with the previous owner or builder. I know how many heads are in each zone of the existing system, and that each zone has a 1" valve and it looks like 1" lateral lines, and that the heads are Hunter PGPs, but don't know what the nozzles and flow rates are (they are all 20' or less apart head-to-head and have red nozzles- seems overkill?). I'd like to get some numbers in my head so I can intelligently plan the zones in the backyard to have sufficient coverage without unnecessary zones or heads.

I have tapped into the 1.5" supply line at the existing valve manifold, but I have ~300' of 1.5" pipe between that existing manifold and the new manifolds in the back yard. Seems like that is just semantics whether it is an extension of the existing system or a completely new one :)


Supreme Member

Posts: 5,298

Location: Metro NYC


Sunday, October 14th 2012, 5:30pm

You possess better means to answer your questions than anyone on the internet, because you can use your water meter to determine the flow rates for each zone in your front yard. Once you know the flow rates and have measured the water pressure while each zone is running, you now have a good picture of the front yard operating conditions.

Obviously, you don't make zones at the end of an additional 300 feet of pipe in your back yard have as much flow as in the front yard zones, because you have to compensate for the pressure lost in the long run of pipe.

Low pressure is a reason to space heads closer together. There is a possibility that your town pressure is subject to occasional fluctuations, and closer head spacing might come in handy.


Monday, October 15th 2012, 11:03am

Thanks for the tips- very helpful. I'll check the water meter today and use the flow of each of the zones to calculate the pressure loss for the 300' pipe to the backyard.

And I'll plan on heads with smaller radius than I was thinking (I was planning for 35' radius).


Monday, October 15th 2012, 8:57pm

Wow- I was kind of surprised. 2 of my zones were over 28 GPM (as measured from the water meter).

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