# Inground sprinklers done today



## mstrlucky74 (Jun 4, 2020)

Had them today and not that happy with the job the guy did . He had to rearrange the sprinklers(pull them out and move them) a few times after I identified area not being properly covered. So my lawn is 40x35 and he put in 4 hunter ultra rotators. The pink represents where he finally put them. 
Before you ask ..lol..he did not do a water pressure or flow rate test. Yes I know he should have. Actually none of the 4 estimates mentioned that . When I asked the said all the houses in the areas had about the same pressure. I know they should have but ..I don't know what to say.

So, to start, does the layout of the sprinklers make sense? He's coming back Monday to fix some of the flower bed sprinklers he screwed up. Thank you very much.


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## mstrlucky74 (Jun 4, 2020)

Should the spacing be equal distance?


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## bernstem (Jan 16, 2018)

That seems a bit of a weird layout to me. I would worry the corners without heads wouldn't get enough water. I would do an irrigation audit to see how even the irrigation is.

https://content.ces.ncsu.edu/landscape-irrigation-auditing-made-simple

45 feet is a long throw for most home rotor heads. They tend to max out at 35 feet which is why he probably staggered the 45 foot sides like that. With limitations on the throw distance, that might have been better with 9 heads in a grid (maybe with rotator heads which have 20-30 foot throw depending on model), but cost would have been more.


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## Ware (Jan 28, 2017)

Yeah I'm scratching my head on the reasoning behind that layout. You should read this. I would recommend reading the whole tutorial, but particularly that section.


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## mstrlucky74 (Jun 4, 2020)

One sprinkler does not have to throw 45 feet only half of that as the other sprinkler covers the other half I don't understand


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## mstrlucky74 (Jun 4, 2020)

Oh well..I didn't know about head to head coverage ..so 4 sprinklers is not enough??


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## Ware (Jan 28, 2017)

mstrlucky74 said:


> One sprinkler does not have to throw 45 feet only half of that as the other sprinkler covers the other half I don't understand


That may get the grass wet, but what you want/need is head-to-head spacing. I would recommend reading the Irrigation Tutorials linked above (in its entirety) to learn more about proper irrigation system design before proceeding.

You will then be better equipped to communicate your expectations to the contractor and will be much happier with the end result. Your contractor has demonstrated he does not know how to design a good system. Unfortunately they get away with this because many people think if their grass is getting wet the system is doing its job.


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## mstrlucky74 (Jun 4, 2020)

Thank you soooo much guys. One last thing.
The water pipe he ran from my main water line inside to the outside is not straight/level it's actually slanted upward quite a bit(not easy to tell from the pic)upward as it goes from the water line to the outside wall which makes me think it would make it harder for the water to get outside ??my wife even said possibly backup? I would think if anything other than straight it should be downward so the water flows easier.

Should there ALWAYS be a backflow preventer part of the system?


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## bernstem (Jan 16, 2018)

The pipe slanting up doesn't matter. Second floor plumbing supply lines run straight up in most cases without issues other than some minor pressure loss.

Not having a backflow is very bad if you are using the same water supply for irrigation as for your drinking water. Almost every municipality requires a backflow preventer to protect the city water supply. If you are rural and on a well it may not be a county requirement, but you risk contaminating your drinking water without one unless the drinking water and irrigation water supplies are completely separate.


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## Ware (Jan 28, 2017)

mstrlucky74 said:


> Thank you soooo much guys. One last thing.
> The water pipe he ran from my main water line inside to the outside is not straight/level it's actually slanted upward quite a bit(not easy to tell from the pic)upward as it goes from the water line to the outside wall which makes me think it would make it harder for the water to get outside ??my wife even said possibly backup? I would think if anything other than straight it should be downward so the water flows easier.
> 
> Should there ALWAYS be a backflow preventer part of the system?


Irrigation Tutorials covers elevation changes too. But to answer your question, the pressure loss on an upward sloping pipe would be negligible (0.433 PSI per foot of elevation change).

Regarding backflow preventers, here again Irrigation Tutorials says it best:



> You should have a backflow preventer on your irrigation system if your water comes from a "potable" (drinkable) source (see next paragraph.) If your irrigation water source is considered potable, then in most places it is illegal to not have the proper local authority-approved type of backflow preventer on your irrigation system. If your water source is non-potable, you generally are not required by law to use a backflow preventer (but not always - some jurisdiction even require them for non-potable water like recycled, reclaimed, and gray water sources.)


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## mstrlucky74 (Jun 4, 2020)

Can the throw distance be adjusted on the head or you have to get a specific head for the throw you want based on water pressure and food rate?


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## bernstem (Jan 16, 2018)

Throw distance can be reduced on most heads. On rotors (e.g. Hunter PGP, Rainbird 5000), reducing throw too much can negatively affect uniformity of irrigation. On rotators (e.g. Hunter MP rotator, Rainbird R-Van), reducing throw has minimal effect on uniformity.


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## SCGrassMan (Dec 17, 2017)

Yeah, I'm somewhere between 9 and 15 heads on a design like that.


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## Utk03analyst (Jun 8, 2019)

When in doubt check Orbit out. The orbit website has a free online design tool that should give you ideals. I'm not sure how many GPM's your system has or your psi. But to get a PGP Ultra to throw 45 feet you need an 8 gpm nozzle and at least 45 psi. https://www.hunterindustries.com/sites/default/files/IC_I20_dom.pdf

I have a side yard that's 40 by 125 and I did the install myself. I have 10 pgp's on 4 zones with 3 rotors max on a zone and I consistently throw 40+ feet. I have 5gpm nozzles on the zones with 2 rotors and 4gpm nozzles on the zones with 3 and I'm on city water at roughly 60 psi and 13 gpm's. The nozzle charts are a must to nail down the distances you want. Head to head coverage is also a must especially when you factor in any wind which will really impact distance. While not textbook and less than ideal your current set-up may work but you really need a backflow preventer if you don't have one some municipalities also require a pressure reducing valve as well.


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## SCGrassMan (Dec 17, 2017)

Utk03analyst said:


> When in doubt check Orbit out. The orbit website has a free online design tool that should give you ideals. I'm not sure how many GPM's your system has or your psi. But to get a PGP Ultra to throw 45 feet you need an 8 gpm nozzle and at least 45 psi. https://www.hunterindustries.com/sites/default/files/IC_I20_dom.pdf
> 
> I have a side yard that's 40 by 125 and I did the install myself. I have 10 pgp's on 4 zones with 3 rotors max on a zone and I consistently throw 40+ feet. I have 5gpm nozzles on the zones with 2 rotors and 4gpm nozzles on the zones with 3 and I'm on city water at roughly 60 psi and 13 gpm's. The nozzle charts are a must to nail down the distances you want. Head to head coverage is also a must especially when you factor in any wind which will really impact distance. While not textbook and less than ideal your current set-up may work but you really need a backflow preventer if you don't have one some municipalities also require a pressure reducing valve as well.


He said rotators, and may be meaning rotors. We should probably clarify which he is using.


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## mstrlucky74 (Jun 4, 2020)

SCGrassMan said:


> Utk03analyst said:
> 
> 
> > When in doubt check Orbit out. The orbit website has a free online design tool that should give you ideals. I'm not sure how many GPM's your system has or your psi. But to get a PGP Ultra to throw 45 feet you need an 8 gpm nozzle and at least 45 psi. https://www.hunterindustries.com/sites/default/files/IC_I20_dom.pdf
> ...


So how would I know?


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## Utk03analyst (Jun 8, 2019)

mstrlucky74 said:


> SCGrassMan said:
> 
> 
> > Utk03analyst said:
> ...


I assumed the distance was 35 feet and you mentioned "Ultra" you had PGP Ultra's "Rotors", Rotor's shoot out one stream of water while rotators shoot out multiple streams of water at once and pictures would be helpful as well.


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## SCGrassMan (Dec 17, 2017)

@mstrlucky74 it will be labeled. Or, if the irrigation installer can't tell you which he means, definitely don't hire him. Most of us here (I think) have the MP Rotators. You need more heads, but they make bigger droplets so they use less water overall.


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