Zone duration seems too long

I may make this upgrade this year since the grass drives my water bill the most. Can the Hunter MP Rotators SR just easily screw onto my current rainbird popups?

The MP rotators have a body and then the nozzles of various capabilities (throw distance, adjustment angles, etc.) are screwed into the bodies. I doubt that you would be able to use the Rainbirds, but maybe they have something equivalent? My new bodies are wider than the old, cheapo heads that I had in. I had to dig out enough area around the old heads to get my hand around them and screw them out, then put the new ones in. Not a big deal at all.

I love 2 things about the rotators. First, they are MUCH easier to control than my own heads with regards to precise angles and throws, so I get far less overspray and can dial in the coverage better than my old heads. Second, the lower flow rate does a much better job of delivering the water to the lawn surface, rather than misting into the air.

Front Yard:
Area: 1100
Available Water: 0.2
Crop Coefficient: 0.7
Root Depth: 6
Allowed Depletion: 50%
Efficiency: 46%

Front Side Yard:
Area: 375
AW: 0.2
CC: 0.7
RD: 6
AD: 50%
Eff: 50%

Looking at the calendar, it looks like about 11 days (Water June 27 and again July 8). Both zones basically get full sun all day long. I’m in Kansas City so we’re look at mid 80s-low 90s, maybe a bit higher

@tpayne, your settings don’t seem unreasonable - I’m guessing that’s clay loam soil based on the AW? Watering every 11 days seems like a long time but I live in the Phoenix area and I’m not sure what’s typical in KC. What ET values are you seeing in the moisture graph details? Assuming you were watering with another controller before, how long were you watering and how many days between?

@azdavidr, the perfectionist in me can relate to what you are saying about the rotators. Since the original concern seemed to about the water bill I wondered what the financial trade offs would be for @tpayne. I’m also curious for my own yard too. I’m probably too lazy to go dig up a bunch of sprinklers, though.

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I’ve been using the Rachio since last year. For the front yard, for the last week ET’s have been between 0.16 in - 0.25 in for each day.

+1 on this seeming like a long time stretch. If you truly have clay it makes sense that the watering is deep and infrequent, but it’s worth double checking. If there is a disconnect on the soil setting maybe it was more forgiving in the winter time than now. Did you get the soil tested, or look it up via the Web Soil Survey ?

Hmmm. Based on those settings I would think Rachio would water when you’ve lost 0.2 * 6 * 0.5 = 0.6". With those kinds of ET values I’d expect watering every 3 days or so assuming no precipitation. Would be curious to see the Moisture Level details.

Anyway, I’m not sure anything is obviously wrong with your settings so I think you might consider the tradeoffs regarding what others have suggested about improving system efficiency if you’re interested.

@azdavidr I looked it up via WSS and I do currently have it set as Clay Loam.

@ldslaron I’ve run two rounds of catch cup tests on the front yard zone so maybe that’s messing with the timing of waterings?

Some folks say that when their homes were built tons of soil were brought in and layered on top of the native stuff. If so that could make the AW of 0.2 too high. Just a thought.

Seems likely. You should be able to tell from the moisture graph details.

The Hunter MP and MP SR’s screw onto a standard 1/2" male NPT (they are a standard 1/2" female NPT), since most sprinkler bodies are 1/2" male NPT they should screw onto your rainbird sprinkler heads.

However, the MP’s need to be pressure regulated at 40 psi (or possibly 30 psi) to get optimum performance and a consistant throw distance. This is best accomplished by switching out your sprinkler bodies with pressure regulated sprinkler bodies (30 or 40 psi). Sprinkler bodies with a check value (either pre-installed or field-installed) will give additional water saving benefits for down-hill sprinklers. Rain bird does sell a similar product (both the pressure regulated bodies and rotator heads), but I’m a Hunter fan.

The MP Rotator heads can be adjusted down by 25%. So, the SR’s would have a throw distance of 8’ - 10’ at 40 psi, 6’ - 8’ at 30 psi, and 10’ -12’ if a non-pressure regulated sprinkler body was used and the static pressure was ~ 55 psi. Note: the SR’s have a higher precipate rate of ~0.8 in/hr vs. the MP standard precipate rate of ~0.4 in/hr, so they are not suggested to be used in the same zone as the MP rotators, but can be with an adjusted schedule time (according to the Hunter tech I called).

The Hunter website has lots of videos and spec tables to help you determine just what you need.


Not sure if this was answered or not @Modawg2k, but the MP Rotators will fit on pretty much and sprinkler body other than Toro. As long as the pop-up piston is a male thread, you are good to go!


@tmcgahey Thanks, I just got a confirmation back from Hunter also that they will work. I may pull the trigger, but I gotta figure out this pressure issue that @comsciguy graciously provided. I know I won’t be digging up sprinkler bodies, maybe just one to check out what’s down there.

I was able to use one of these recommended by @JPedrego. Based on where the tap was to the irrigation valves relative to my hose bib, I knew that the pressure at my heads was good based on the hose bib reading.

Start here, and read a few posts down.

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This is only about 20 feet for me, same side of the house, just bib in front yard with valves on other side of fence

You can use a pressure gauge on the sprinkler heads to measure your pressure at each head to determine what the predicted throw distance would be ( The gauge at that link is kind of costly. That website also sells the adapter body that you could use with another pressure gauge.

Also be sure to shop around the various web stores for the best prices. Sprinkler Warehouse has the best price for the standard MP Rotators and 40 psi sprinkler bodies, but are more costly for the specialty MP Rotators (e.g., the MP Corner). has a better price for the specialty rotators and 30 psi sprinkler bodies. Both sites offer free shipping for orders over $149 and the free shipping only took 3-4 days. So shop around for the best deal and be sure to account for shipping cost.


Dont feel too bad about your results. A few years ago i remember seeing a paper where results were anakyzed from a large number of audits across the country. The researcher looked at residential, commercial and sports field irrigation systems. The average of all in each category was a sad 50 percent. So you are average, when it comes to DU.
What can you do to improve your system?

  1. Measure distance between heads in the rotor zone. If you are not getting head to head coverage, consider adding additional rotors or rotating nozzles (like MP Rotator). What nozzle is installed in those rotors? Look at the manufacturer specs. Maybe you need a different nozzle, but remember the size of poly pipe or PVC limit how many gallons per minute. Check poly pipe and PVC charts.
  2. Check alignment and adjustments of rotors. If a rotor is sunken or tilted, that can really throw off uniformity.
  3. Buy a Hunter MP Gauge and measure the pressure on your sprays. Shop online to get the head adapter and get an $8.00 pressure gauge. If your head pressure is more than 50 psi, you need pressure regulated heads that maintain 30 psi. If your sprays are going off like missles, you have high pressure.
  4. Look at your spray head spacing. You should have matched precipitation. Google that term to get a textbook definition.

Hope i have given you a few places to start.


I thought I would report back since I now have all MP Rotators on my lawn. The backyard efficiency went from 56% (rotors) to 76%, and the front yard went from 49% (sprays) to 71%. The front yard is running without pressure regulation and probably loses some efficiency due to high pressure, and it was windy when I ran the test. Should save about 15-20% on water or 40K gallons/year, about $50/year here. Thanks for all of the tips and hope this info helps someone else make a decision.


Wow, nice job @ldslaron. That’s a huge improvement!

Thanks. $50/year isn’t all that much but having the lawn watered evenly should make it worth it.