You are not logged in.

Dear visitor, welcome to SPRINKLER TALK FORUM - You Got Questions, We've Got Answers. If this is your first visit here, please read the Help. It explains how this page works. You must be registered before you can use all the page's features. Please use the registration form, to register here or read more information about the registration process. If you are already registered, please login here.


New Member


Saturday, April 26th 2014, 2:50am

Dumb question? Cap or Plug for 1" Poly

Simple question, but I can't seem to find the answer via You-Tube or elsewhere. If you want to cap a 1" Poly line, where do you get the plug or cap? I don't see parts on Sprinkler Warehouse for that. This seems like it would be a fairly common need.

I wish to add one sprinkler head to a zone. I do have a small fear that the water pressure would then be reduced in another head. If I don't like the result I would like to have the ability to cap that addition. How do I do that?


Central Irrigation

Supreme Member

Posts: 371

Location: Central Minnesota


Saturday, April 26th 2014, 7:54am

Here in Minnesota, capping a line can cause leaks, since you would have a section of line that would trap and hold water over the winter, which would freeze and crack the pipe. Your best bet would be to connect the new line, test, and if not to your liking, eliminate the new line at the connection point.

If freezing is of no concern to you, then a 1"x1/2" fpt elbow and a 1/2" mpt cap will make a makeshift plug. I would still advise eliminating at the connection point, however.


New Member


Saturday, April 26th 2014, 5:02pm

Ah, that's makes sense. In my particular case freezing is a concern in northern Kansas. However, my new line is for a berm that is increasing in elevation a couple feet, thus a high point, and not really an issue for freezing at that point. However, I guess I can see during blow out your really blowing 20 feet of water against a capped line and after releasing air pressure on that section you have 20 feet of water that settles back into the lower elevation, not good either. In which case your suggestion to remove the section is the best bet. This must be why you can't find caps because it's perhaps bad practice.





Sunday, April 27th 2014, 9:03pm

Pressure inside your irrigation line will be the same in the new section as it is in the old section when blowing out or watering or whatever. In all actuality, since the pressure is the same and your new line is higher, it will drain out into lower sections because of gravity.
If you're worried, you can fold the end of the line over during use in season then unfold it for blow out (it won't leak, trust me), put a hose barb X male pipe thread adapter on the end then put a threaded cap on it, put a valve on the end or put a hose barb plug in.
Those plugs are sold everywhere, you should be able to find one easily.
If water were to flow back into the system, just cycle that station on and off a few times to blow it down stream as it drains. There's no rule saying you can only turn on a valve once for blowout.

Good luck

Rate this thread