Single PRV supplying multiple irrigation zone valves

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RandyB

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In every online search I've done, the usual piping is from the main into a backflow/PVB then into a manifold of control valves, one for each zone.
Then for those drip only zones, a PRV (with or without a filter) is put after the valve to reduce the pressure down to 30psi or under then on to the individual emitters, bubblers, whatever.
Assuming a normal residential lot with say 6-8 zones, normal main pressure (say 55-60psi), and a number of individual zones are drip only (ie no turf rotors, etc), and the max run in any one zone area is 100ft and would be fed to that local drip area by 3/4" poly and then 1/2" or 1/4" feeder lines (not all on one single lie but branched appropriately).

Question: Instead of having each zone consisting of a control valve, followed by a PRV then 3/4" poly delivery to the drip area, what are the cons/negative in having just one PRV (ie 30psi) supplying those multiple control valves that supply just drip zones? Assuming that there is sufficient pressure and flow at the local drip areas.

Seems like there shouldn't be any issues. 30psi out of a PR is sufficient for the major control valve vendors, so should be no issues open/closing. Pros/positive would be less numbers and cost in PRVs, simple install, less stuff, in an irrigation box.
 

WorthFlorida

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For some reason, several posts just showed up from around Aug 1st - 8th, 2022, today is Aug 31st.

The answer is yes, one PRV is OK for the entire drip system, however, on the negative side the cost for each is small and should the PRV fail you do lose the entire drip system. "Don't fix what's not broke" as the saying goes. If everything is working with no issues, leave it alone.
 
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Breplum

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We only use PRVs that have double unions. That way it is a simple and easy swap-out should it fail.
When they do fail, they increase pressure, so at worse, you have overpressure/higher flow for a short period.
One PRV is the way to go.
 
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