# Good Pressure Poor volume



## BobDolesky (Jul 6, 2020)

Good afternoon! I've been looking into doing a sprinkler system, initially, I started out with just simple 20 ft hoses to connect couple simple on top of lawn sprinklers in a series, very poor performance. Even poor performance in one of the oscillating sprinklers that essentially create a wall that goes back and forth, high and wide covering like 7500 sqft, but i was basically getting 2000 at best. Currently on single high performance impacts, but I'm want to move to in ground system utilizing a system like Rainbird DIY kit that works off of faucet timer. However, after running the performance tests, my pressure was about 50 PSI, but I'm only getting about 4 GPM. I ended up contacting my builder since its a brand new house only a month old and he sent out a plumber, basically really abysmal information/results. He basically went and just cranked up the PRV to 110 and had me run the sprinkler, well great performance, amazing, but from everything I've been told and read, thats really bad for the house. So I had him crank it down back to 70, which really isn't clear to me if thats bad or good, different searches are inconsistent, some say max 80, some say max 60 PSI. So with everything, my performance is essentially about 5 GPM, still really not going to cut it if I want more than a few heads on a line. The plumber told me I have 1 inch City line, but to the house its 3/4. My garden faucets are post the PRV thats inside my house. I tried inquiring what a solution would be, but he didn't really know the answer.

Trying to figure out a solution, which will definitely require a professional. My best guess is that a 1 inch line will have to be replaced at the meter ran through yard than essentially branch to a Backflow preventer and cutoff that is required by code and either go with the traditional full in ground valve/series or create another faucet and go with faucet route again, then just let the 1 inch merge into the 3/4 already running into the house? Any suggestions or help would be great! Thanks!


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## Thick n Dense (May 7, 2019)

Feet of the run maters for flow loss. If going from 1" to 3/4" back to 1" is only 1 foot, it won't be that big of a deal.

the longer the run the more flow you loose... also, the loss is logarithmic, the more pressure you have to work with the more the loss will be.

Are you trying to DIY or just understand? I see this is your first post....


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## BobDolesky (Jul 6, 2020)

Both Understand and DIY. At this point, at a minimum I need a Plumber to run a 1 inch off the mainline to use for the irrigation system. Code requires a backflow preventer with cutoff to be 12 inches above your highest sprinkler also requires licensed plumber, so basically all system here, and least for the few in my neighborhood uses that and it's typically near the exterior garden spickett hidden under a big obvious fake rock. The yards here are pretty small, and close together and small front yards, and not far at all from the meter off the street.

I'll ended up doing DIY for the remainder of the systems after the stuff a plumber would put in to run the line off the meter


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## bernstem (Jan 16, 2018)

You should have better flow than 5 GPM with a 1 inch copper main line. Even if it is 1 inch to the city shut off and 3/4 inch copper after that for a few hundred feet in the yard, you should be getting 10-15 GPM. Something after the main line is restricting flow. That could be anything, but your water meter size and line to the hose spigot are likey bottle necks. Most likely, you have a long 1/2 inch line to your hose spigot and your hose flow is not what you would get with a 3/4 or 1 inch line to the irrigation. If you are lucky, you have a drain valve somewhere right after the meter. I would check pressure and flow there rather than at the hose spigot.


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## hsvtoolfool (Jul 23, 2018)

BobDolesky said:


> So I had him crank it down back to 70, which really isn't clear to me if thats bad or good...


That's the upper-end "safe" zone so you're okay. A plumber I actually trust tells me the target is 60 to 70 PSI max.



BobDolesky said:


> My best guess is that a 1 inch line will have to be replaced at the meter...


I agree 100%. Do it right and eliminate tons of headaches and worries. Install a 1-inch sch 40 PVC "T" for the irrigation mainline and then go into a reducer to tie back into your home 3/4" line. The 1" irrigation mainline can then be trenched to where it's needed. I'd install the irrigation backflow preventer and PRV right at the valve manifold.

Bigger pipe is always better. It drastically reduces water velocity, which in turn lowers the chance of water hammer and pipe erosion damage.


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## BobDolesky (Jul 6, 2020)

hsvtoolfool said:


> BobDolesky said:
> 
> 
> > So I had him crank it down back to 70, which really isn't clear to me if thats bad or good...
> ...


That's basically what I'm thinking, although If I'm understanding the lingo right, you're saying put the Backflow preventer and PRV at the valve manifold right next to the water meter by the street? If that's the case, I think that isn't really an option since it was explained to me that portion needs to be 12 inches above the highest sprinkler in your system, so they install that typically next to the side of a house and hide it with an artificial rock.

After a little more research and figuring out a solution, I think I actually did find an doable option that would essentially mirror my current setup, but let me take it underground and not break the bank. Basically my setup now is Two Orbit 4 Outlet 1 timer faucet timers with Orbit High performance impacts that have 100ft diameter coverage that I schedule the watering to happen consecutively, so that only one sprinkler is going at a time. Currently on the front of the house I use 1 impact to cover the main front yard and does well enough, then second hose runs to the back covers part of the back yard, then other timer on back of house faucet runs a 100 ft hose around the hose to cover the other small part of front yard on other side of driveway, and another hose is in back yard covering a good portion. I currently only have a segment of non-coverage, but thats a product of I didn't get more hoses because I was planning to do the in ground DIY kits. I found Rainbird has couple different in ground impacts the Maxi and Mini paw, which they describe as being great for reclaim water systems, and based on what I'm experiencing, impact sprinklers offer me the best performance with the low volume of water that I have. So thinking of moving to those. They run about $18, I would get probably 8 of them. Then I would need the fittings and Poly pipe to run around to supply. Few quotes I got for the 1 inch water line and backflow, I'm looking at over $800 just for that.

The only thing holding me back from going full in ground suite is I'll only be living in this house for 3.5 years before moving again. So trying to find the best value that meets the irrigation needs verse ROI.


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## bernstem (Jan 16, 2018)

There are backflow preventers that do not need to be installed at the highest point in the system. A Reduced Pressure Zone Backflow Preventer, for example, can be installed in your basement, but you need drainage in case it leaks. Backflows that can be installed below the highest point in the system are also more expensive.


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## BobDolesky (Jul 6, 2020)

bernstem said:


> There are backflow preventers that do not need to be installed at the highest point in the system. A Reduced Pressure Zone Backflow Preventer, for example, can be installed in your basement, but you need drainage in case it leaks. Backflows that can be installed below the highest point in the system are also more expensive.


Great information! I'll inquire about that as an option. Much rather have that than the above and a big obvious fake rock


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## hsvtoolfool (Jul 23, 2018)

BobDolesky said:


> ....you're saying put the Backflow preventer and PRV at the valve manifold right next to the water meter by the street?


I made no assumptions where you might put the manifold. You must decide where the valves will go.



BobDolesky said:


> ...I'll only be living in this house for 3.5 years before moving again.


Yeah, I probably wouldn't bother either. Whenever someone asks specific technical questions about GPM and PSI, I always assume they are planning a full irrigation system for their permanent home. It never occurs to me they just want a nice lawn for a couple years before they move.

For short term irrigation, I'd just get a nice Eley reel and 100' hose cart combo. It actually makes using a hose fun. Well, okay. Not "fun" fun. But it's not a gigantic nuisance anymore.


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## bernstem (Jan 16, 2018)

I wouldn't bother with an in ground irrigation system for 3 years.


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## Thick n Dense (May 7, 2019)

I made an above ground valve system off a normal hose spigot Using pvc fittings and hunter valves.
I run regular hose from the valve to the sprinkler.

Completely removable with minimal investment and I can control from my main irrigation controller. 
In your case, you'd take these items to your new house and use when you really make a system.

Still not worth it unless you plan on seeding ... imo


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## RVAGuy (Jul 27, 2020)

> There are backflow preventers that do not need to be installed at the highest point in the system. A Reduced Pressure Zone Backflow Preventer, for example, can be installed in your basement, but you need drainage in case it leaks. Backflows that can be installed below the highest point in the system are also more expensive.


Be aware that some areas (myself included) require RPZs installed 12" above the highest sprinkler head. DCA's (double-check-assemblies) are not allowed in my area and an inspector will fail you for it. It's worth knowing, especially if you will be selling the house soon. It will be caught upon inspection and have to be fixed.


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## TSGarp007 (May 22, 2018)

bernstem said:


> I wouldn't bother with an in ground irrigation system for 3 years.


Good point. Unless comp homes in the area all have it, and potential buyers will expect it. If this is a rental then obviously don't do it...


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