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New Member


Friday, July 20th 2012, 9:18am

Can I add 3/4" inline pressure regulator+filter at start of 1" sprinkler system?

I have a question that involves a functional component and and a sprinkler component. Background: I am converting one of my existing 1" sprinkler system lines into a 100% drip line. I will be converting 3 downstream sprinkler heads into 3/4" drip line (2 into drip, 1 sealed) and will be adding a 3/4" T-split to add a drip line off the main line. My water PSI is about 100 at the source. I was going to place an inline pressure regulator + filter at the start of the entire line. I bought the 30PSI regulator, which is 3/4". So the line would go Source/solenoid --> 1" --> 3/4" --> 1" --> rest of drip line. FYI, the total length of the line from start to end would be about 150' with three drip line extensions, each about 20'.

First, is the use of a 3/4" inline regulator ok in this case or should I increase to the 40PSI 1" regulator?

Second, I'm not sure which thinking is correct: On one hand, going from 1" to 3/4" would drop flow and should increase pressure. But then pressure is being regulated. Would flow decrease even more after 3/4" to 1" increase? Or would any change in volume be functionally non-existant?


Supreme Member

Posts: 5,325

Location: Metro NYC


Friday, July 20th 2012, 10:05am

Treat drip zones with filters and regulators downstream of the zone valve(s)


New Member


Friday, July 20th 2012, 1:51pm

This actually is downstream of the zone value. I am converting the entire zone #4 to drip line only. So I have main water supply into 4 zones (with solenoids, etc), then a 1" pipe off of the zone. THEN I was going to add the inline regulator/filter so that I would only need to install it in one area and have everything coming off zone4 be drip.

My biggest concern was that the entire zone4 has 1" delivery pipe through yard and that I was going to put a 3/4" regulator at the start of the entire line. I was largely worried that I would cause some negative effects by going from 1" (off of zone valve area) --> 3/4" then back to 1".

An alternative would be to add the pressure regulator and filter at each 3/4" offshoot from the main 1" zone 4 pipe. But then I'd have 3 separate pressure regulators/filters instead of one (no big deal if its the right thing to do.)

Does that help any more? I'm still learning all my terminology and fear I misused the word "main" to mean the line I was prioritizing, but not "main" in terms of main water line, etc.

Thanks for any help you might be able to give.

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