Pressure regulator @ street?

[70runner]

4 acres of hilly terrain, house sits on hill, about 100ft higher than street. Main 1.5" water line from street goes to meter, then up to backflow preventer, then underground where it splits to 2 main circuits. One circuit feeds house and several perimeter sprinkler valves. The other circuit feeds an avocado grove of about 300 trees. The grove valve (Bermad 900D volumetric valve) can be seen in the pic beyond the backflow.


PRV at the house entry set to about 60psi. No other regulator in either circuit.

Recently we stumped about 200 avocado trees and capped the corresponding sprinklers. A day or 2 after completing the caps, noticed a pool of water near some sprinkler valves. Long story short, turned out to be a cracked pvc cap on an unused branch off the 1” house circuit. A coincidence that the cap failed after 200 sprinklers were capped on the grove circuit?...maybe, maybe not.

To figure out what was going on I checked unregulated pressure at the house on a hose valve, 95psi. The length and rise of the house supply would suggest the pressure is higher at the street. I left the gauge on the hose valve and activated the grove circuit. The pressure dropped to about 70psi and stayed there for the 30min I ran the test.

So my question to ye plumbers is should I put a PRV on the house and/or grove circuit, at the street?

 

[Jadnashua]

Pressure drop with altitude changes amounts to 0.433#/ft change. Then, there are friction losses. You could put the PRV at either end, but as long as your pipes are designed to handle the pressure, I'm not sure it really matters. You'd probably find it easier to do the maintenance in the house rather than down at the roadway. Dropping 25psi with flow is a function of friction which would vary with the flow.

 

[Sponsor]

 

[70runner]

There is a PRV on the house circuit at the entry to the house. Given the cap failure, I'm wondering if I should PRV the house line at the street. AFAIK, the house line is schedule 40 1" pvc.

 

[hj]

Capping ANY number of outlets did NOT change the pressure in the system so that is not why the cap cracked. I assume the PRV at the house is functioning since you did NOT test its dynamic pressure. The drop in pressure when you turned on the grove's water is due to the limited capacity of the backflow preventer. Given the "raw" pressure you probably do need a PRV on the grove, but it must have sufficient capacity to water properly, which means you might have to use a larger valve and reduce its inlet and outlet to match your pipe size. If you PRV the house line at the street, you will lose the pressure caused by the elevation, unless you set it higher to compensate for the loss, which might negate the effect of the PRV.