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Spigot Before PRV???

DawgPaw

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Mar 8, 2014
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USA
I am in the middle of replacing the half inch pex with three quarter for my outside water faucets. Our pressure and volume is horrible, and it helped on the first one that I tested.

Then I started to wonder if there is any reason not to run them before the pressure reducing valve. It comes into the house around 100psi. Are there any concerns about too much pressure or water hammer?
 
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Wheelingit

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Maryland USA
I don't think that it is a problem for the pipe, the thing that would concern me is a solid fitting. You don't want a fitting to blow undone. I get a little nervous over 80 psi
 

nadogail

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Coronado, CA
My lawn sprinklers are connected up stream of the pressure regulators on my rentals. Been that way since they were built. We have not yet seen a problem with that.
 

sixty4

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CT
My outside faucets all before the pressure reducing valve and outside shower. Pex can handle 100psi water hammer only if piping not secured or a fast closing valve. I have quarter turn faucets outside but no water hammer.
 

u2slow

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BC
My outdoor hose bibs are street pressure. (before PRV)

If flow is what you're after, make good choices for the valves. The first ones I put in (frost free + built-in backflow preventer) were horrible. Went with a more basic one next and dropped the backflow. I can always add a screw-on backflow widget later if I care.
 

Shiftless

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East Bay SFO
My lawn sprinklers are connected up stream of the pressure regulators on my rentals. Been that way since they were built. We have not yet seen a problem with that.
Modern sprinkler heads are designed to run at around 30 psi. Often times higher pressures will result in misting which wastes water through immediate evaporation and when the wind blows the fine droplets away from the lawn or other landscaping being irrigated with the sprinklers.
 

ScottsGT

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Lake Wateree, SC
I’m looking into doing this myself for my spigot on the back of my house. I use it to feed my pressure washer and the 1/2” feed is very borderline on getting it done.
 
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DawgPaw

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USA
This was exactly my issue. Switching to 3/4 helped, but I would still like a little more.
 

FredWanaker

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NorCal
front spigot is ahead of prv. Everything else is after the PRV. For us, there is no need to run 90 PSI to a back hose to wash off the b ack patio, sprinklers, or hand water a few plants. When I want to really clean something I fire up the pressure washer.
 
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DawgPaw

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USA
My PRV is out at the street on the meter 200 ft from the house, so I'm only going to get what the 3/4 pipe can provide. My PRV is set at 70psi.
Ahh that’s how my old house was, but with 3/4 PVC there wasn’t an issue. You should look at some friction loss charts, because I bet what you are getting at the house is pretty low!
 
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DawgPaw

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front spigot is ahead of prv. Everything else is after the PRV. For us, there is no need to run 90 PSI to a back hose to wash off the b ack patio, sprinklers, or hand water a few plants. When I want to really clean something I fire up the pressure washer.
My issue is that I’m only getting 40 psi, and the GPM’s through 1/2 at that pressure makes car washing a pain.
 
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DawgPaw

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Modern sprinkler heads are designed to run at around 30 psi. Often times higher pressures will result in misting which wastes water through immediate evaporation and when the wind blows the fine droplets away from the lawn or other landscaping being irrigated with the sprinklers.
Maybe the shrub nozzles, but the rotators go up into the 60’s on the chart. Then when you factor in friction loss 80 psi from the house is about right for me.
 
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DawgPaw

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USA
My outdoor hose bibs are street pressure. (before PRV)

If flow is what you're after, make good choices for the valves. The first ones I put in (frost free + built-in backflow preventer) were horrible. Went with a more basic one next and dropped the backflow. I can always add a screw-on backflow widget later if I care.
I’ve noticed this as well!
 
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DawgPaw

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USA
I don't think that it is a problem for the pipe, the thing that would concern me is a solid fitting. You don't want a fitting to blow undone. I get a little nervous over 80 psi
I’m thinking about a separate PRV set at 80 for the sprinklers and hose bibs
 

Sumboodie

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Mar 20, 2021
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AK
My issue is that I’m only getting 40 psi, and the GPM’s through 1/2 at that pressure makes car washing a pain.
Should be plenty fine.

My water pressure is 20-40psi, 1/2" pex for spigots and 200ft of hose.
Not been an issue running a pressure washer.
 

ScottsGT

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Lake Wateree, SC
Ahh that’s how my old house was, but with 3/4 PVC there wasn’t an issue. You should look at some friction loss charts, because I bet what you are getting at the house is pretty low!
I was there when the county installed the PRV. They set the pressure on the front yard hose bib which is at the end of the 1/2” runs throughout the house. Back yard bib I use for the PW is right off the main coming into the house, just stepped down to 1/2”.
This all started after I moved in and had T fittings splitting. Plumber came out and my bib pressure pegged his meter at 100 psi.
 
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