Hunter watering times


I logged on to Hunters run time calculator and got some long run times. I have 4 zones and they are all grass. Live in the Kansas City Missouri area. They suggest I run my rotary head for 24 mins and three times a morning and three days a week. Then the spray heads are suggested to run 7 mins, three times a morning and three days a week. I have a must flat sunny yard with clay loam. Does this seem obsessive?? That’s just over 3 hours a day and 9 hours a week. That seems like a lot!

How long does everyone else water?


I also thought that rotary times were very long until I timed how long it takes for a full rotation of the head. This can vary from head to head so I would suggest going out to your rotary head with the zone running (made easy with the iro) and see how long it takes for the head to make a full pass. Once you have that, it might make sense why the time is 24 minutes. It could only be 10 rotations or something like that which would be with in reason.

As for spray heads they cover less area with similar a gpm. There for don’t require as much time.

A quick look at the precipitation per hour of a Hunter rotary and spray head show that the suggested times are pretty close.

Spray head = 3.89 inches precipitation per hour
Rotary head = 0.81 inches precipitation per hour

So they multiplier would be 4.8 more water applied every hour with a spray head. So in this example you ran the spray head for 7 minutes you would have to run the rotary for 34 minutes for the same coverage.

I hope that helps. Now with your iro you can make adjustments when every you what as you see fit.


Okay, just now I scheduled a watering time with the new 1.3.1 update. Rachio recommended I water ever 4 days for 24 minutes total per day. Rotary heads are set at 7 mins and spray heads at 5 mins.

Hunters weekly run times are suggested at 3 hours and 9 minutes per week.
Rachio’s weekly run times are 48 minutes per week.

Why are these so far off and which to choose?


@conrad314‌ We did some research on your durations internally today and here’s what we found:

  • Kansas CIty, MO typically gets a lot of rain in May & June - an average of 5-6 inches/month. ( and (

  • The rainfall value that we get from the NOAA 30 year average (spread over the last few days of May & first 11 days of June) is about 0.21 in/day

  • We come up with a daily precipitation loss this is also about 0.21 in/day. Which is about right when comparing here ( The values in those papers are for crops, not grass, unfortunately, but they’re in the ballpark.

  • Our system basically came to the conclusion that your lawn on the average needs little water over the the next couple of weeks.

  • Kansas CIty, MO area gets a historical average of 5.5" of water in June, but in a given year, that could be 2 inches or 8. Our Weather Intelligence will take care of most of the over-watering situation, but you may need to dial up durations when their area gets less water than the average - we hope to have our intelligence go the other way in the future, dialing up for you.

Let us know what you think.


I really appreciate you guys taking the time to run the durations for me.That greatly helped me wrap my head around the differences. Should save quit a bit of water and money. I will watch the weather, watch for signs of stress and ramp up accordingly. Looking forward to the Iro dialing up, in the future. I have faith it will be worked out. Thanks again for the explanation.

This is why I went with the Iro. Great product, great support!


Conrad what type of turf grass do you have?
This is important since the H2O needs varies upon what type of turf you have. There should be a average needed available thru a local agricultural extension office. Here in central North Carolina Fescue turf is the major grass. NC State university recommends an inch per week as a turf crop. Thus it is also important to know the precipitation rate your zones actually apply, not just what a Hunter or Rain Bird book says they do. Big difference between the book and actual field performance.
In my line of work I find that the design and installation of an irrigation system generally lacks water saving hardware such as check valves and pressure regulating rotors/sprays.
You have probably addressed these issues so sorry if I am plowing old ground here.
My point is that for any smart controller to work well the core of the irrigation must be as efficient as possible and we must understand its application rates per zone.

Hope this helps