Can my irrigation be (easily) improved?

A lot of you guys around this forum share more valuable advice than I can get from my landscapers or at the local Home Depot. I’m hoping you can offer some of your expertise to see if my yard irrigation efficiency can be improved. I have a small lawn in Arizona, on a slope growing Bermuda. What is making my efficiency be so low is likely the non-rectangular layout. This image shows the sprinklers numbered in RED, and the Orbit catch cups are shown in YELLOW in with the milliliters accumulated in a 10min test.

Plugging them into the Orbit online calculator leads to about a 56% uniformity, which I assume means a 56% efficiency in the Rachio settings for Flex. You can see that the biggest issue is likely that the are at the top, especially in the top-right part of the yard where the curve is have the weakest coverage. Where the spray areas all overlap in the center areas, the water accumulated as about 3 times the weaker areas. I’m guessing that adding or moving heads would make an improvement, but that isn’t an option right now due to the rip up involved. Could I replace or adjust some of the nozzles in some areas to improve the coverage. Right now they are all slightly over-spraying to the closes edges of the lawn, but as far as I know that’s the best that I can do. Any advice or ideas would be greatly appreciated!


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You certainly have a lot of overspray on the hardscape. I would seek out the advice of local irrigation distributors in Phoenix, if that is where you live. Check out the Toro Precision Nozzles or the Hunter MP Rotator. It looks like you have a mix of nozzles. An irrigation system should have matched precipitation. Look at some of the sprinkler design manuals at Toro Irrigation, Rain Bird or Hunter. Each of these companies provide some great information for homeowners. Also check out, the website for The Irrigation Association.

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@robertokc. I will definitely take a look. Thanks a ton for your advice!

Also make sure that the pressure at your heads is 30 psi. If not, install a regulator at the valve.


Wow, that’s a great pic illustrating your zone, heads, and catch cup results. 7,8 and 9 seem to be your biggest offenders. But, rather than change nozzles and risk sidewalk run-off, maybe get 5 and 6 to throw more water up the slope?

Agree with @robertokc… matched heads @ 30-40 psi are the best bet for even coverage. I would certainly invest $50 in MP rotators or something equivalent before adding new heads to the zone.

@johnny2678. Thanks for your comments. I plan to take your and @robertokc 's advice and head over to my local irrigation shop.

FYI, the annotated picture was created pretty easily with a PC tool called SnagIt. Extremely easy to use and reasonably priced for what it does.


@ronjonp Thanks. I’m guessing that’s something I would hire someone to check ?

You could hire someone or get a gauge like THIS. One easy check too without needing to buy anything is check the top of your spray bodies & look for a ‘PRS’ call out. If it has that you should be good. ( PRS is a ‘Pressure Regulating Stem’ which should set correct nozzle pressure )

I found this one at home depot when I was thinking of getting one. Also, if you recently moved into your house your home inspection might have the number in it. That’s how I found out my water pressure.

@ronjonp and @JPedrego

Thanks for the links, they are helpful for sure. I’ve been in the home know for 20 years, and we’ve had our irrigation maintained for us. With the Rachio I’m finding that I want to take that maintenance over to get rid of the inefficiencies. So, is there a way to look at if pressure regulators have been installed? Would I just open the valve box and look for something like the link to the regulator that @ronjop included in the previous post ?

If you can’t find any pressure regulators installed, I’d just spend the ~$25 and get the gauge like @ronjonp mentioned. If you’re readings are coming in outside the 30-40 PSI range, then replace your stems with the PRS variants he mentioned. Like these.

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There are several ways to reduce pressure on a system:

  1. If water pressure is off the charts, have a contractor install a Wilkins, Febco, Apollo or Watts brass pressure reducing valve after the backflow preventer.
  2. Check to see what electric valves you have. If they are Hunter valves you can screw on a Hunter AccuSync to reduce pressure on a zone. 30 psi for sprays and 45 or 50 psi for gear drive rotors.
  3. If you have just a few sprays you can unscrew the internals of a standard spray body and replace it with a pressure regulated version. For example, Rain Bird calls their pressure regulated spray 1800 PRS. Hunter calls their product PROS-xx-PRS30.

Hope this helps!

Good product to easily know what your pressure is like.

@robertokc Very helpful. I checked my valves and they are indeed Hunter. I plan to hit this project over the weekend, and will follow up here with the outcome. Thanks to all for the great advice!

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@robertokc Based on the 1st picture, it looks like my existing setup is what you’re referring to in #1, correct ? It also looks like I have a different valve for the grass than the other 3 drip zones. I can’t tell the brand. Based on all of this should I look at option #3 or is #2 still an option ?


Yes, the Watts product appears to be a pressure reducing valve. That is usually installed after the backfflow. Your electric valve resembles an old Buckner valve. They are out of business. Is the valve brass? If you have high water pressure you can try adjusting the pressure reducing valve or install pressure regulating sprays. Drip zones are supposed to have a drip zone kit (valve, pressure regulator and filter). Looks like your system is pretty old. Check out the Watts model on line to make sure it is a pressure reducing valve.

I looked at the Watts pressure reducing valve again. The tag says it is preset at 50 psi and can be adjusted between 25-75 psi. If you have high pressure try turning the screw down.

@robertokc. I’ll pick up a gauge and will give it a shot. Any downside for the rest of the house if I need to reduce the pressure at the regulator for the sake of the irrigation? I have a pool and whole home water softener in case it matters.

Well it would result in your whole house having lower water pressure. I prefer my showers with good pressure so I wouldn’t want to do that but that may just be me. Never had a pool or water softener so I don’t know how those would be impacted. An inline pressure reducer after the sprinkler valve is also an option and might be cheaper than replacing every sprayer with a pressure regulated ones depending on how many sprayers you have. Would take more work though since you would have to dig the valve up and do some pipe work.

It is just the reverse at our home. The sprinklers are tapped off prior to the pressure regulator. An in-home burst pipe can be a disaster.