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Bryan the Homeowner



Monday, January 14th 2013, 11:16am

1" Backflow on a 3/4" Tee??

Hi There,
Our builder placed a 3/4" stub on our 1.25" copper mainline to the house. My per zone usage for a set of rainbird spray heads is just under 12 gpm for each of 2 seperate zones, the other 2 are both drip. The Total length of my Mainline run (to my valve box) is pretty small, maybe 60' straight to the backyard from the side of the house. The designers at Rainbird suggested a minimum of a 1" Backflow and I have a couple of question for ya'll
1) Do I need to replace the 1" x 1" x 3/4" reducing Tee with a [1" x 1" x 1" standard Tee], or can I connect to that 3/4 without too much worry?
2) there is currently a 3/4 backflow attached, courtesy of the builder for the front yard drip system (which they put in before the sale). Any chance I could simple stick with this or is rainbord right on track that I really need to move to a 1" backflow?
Thanks in advance!


Supreme Member

Posts: 5,294

Location: Metro NYC


Monday, January 14th 2013, 1:56pm

Backflow preventers have very high flow ratings, so you can feed 12 gpm from a 3/4-inch device


New Member


Wednesday, January 16th 2013, 7:07pm

As far are the reducing T's. I would not change what you have, but if you are putting in something new it can't hurt to go to 1" . But your flow is pretty low, so you can't go wrong either way.

Bryan the Homeowner



Friday, January 18th 2013, 9:49am

Thanks Guys, thats exactly what I needed

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