Agrilife Extension

I am a new user of a Rachio 3 16 zone system. I have a large yard in Richardson, TX that covers two lots so all 16 zones are used. I use a LOT of water in the summer, especially when temps hover around 100 for days at a time.

Before I bought the Rachio, I utilized a traditional controller. A couple of years ago I learned of the Texas A&M Agrilife Extension’s “Water My Yard” app/service. For those unfamiliar, the folks at Agrilife came up with a formula that takes into account humidity, rainfall, sunlight, wind, and a whole bunch of other stuff I don’t entirely understand, and they come up with an “effective rainfall” for a given week. On their app you load some basic information about your lawn (no where near as detailed as Rachio), mostly the type of heads you have. Since they work specifically with water districts in Texas they assume warm weather grass and, I believe, standardize on bermuda (the most common in my area). Each week I receive an email (or find it in the app) that tells me how long to run my rotors and how long to run my pop ups. This is based on the rainfall and conditions from the prior week. The problem with this service is that it requires a lot of manual intervention by the user. Basically you run your system in “manual” mode (not really one of those on traditional controllers) for the duration they recommend. It has worked successfully for the most part for me, except when I forget to run or turn off… Being out of town for an extended period botches everything.

Anyway, now to my question/concern: How does Rachio determine run times and when to run based on rainfall? This week we had basically 3 days of nice constant rain… Tues, Wed, Thursday I believe. Rachio had originally scheduled to water for 58 minutes on Thursday I believe but skipped and scheduled next run for Sunday (today) with another full run scheduled for Thursday. Basically two full waterings. In the meantime, the WaterMyYard app send notice that I do not need to water at all this week. Zero. I expect there to be some difference of course, but 2 hours of watering compared to zero seems way off.

I went outside and finger tested some soil and mine is still moist in beds and under my lush bermuda in full sun, yet it was scheduled for a full 58 minute water starting today. I scratched my head and skipped today’s run. (Much more convenient than the old controller I’ll say in this regard.)

So how does Rachio calculate runtimes and schedule? It seems to always schedule the same 58 minutes per watering, even though we had a ton of rain ending just 3 days ago. I had thought that the amount of rainfall would be taken into consideration, but is Rachio only skipping when it is raining and does no other calculations? Or am I missing something? I had planned on a period when I need to “dial in” my settings to achieve the best results, but this just seems way off and maybe I misunderstood how the system work?

I should have mentioned my schedule is Flex Daily and Smart Cycle. Only override is I have it avoid Friday and Saturday for convenience.

Many thanks for whatever information you can lend.


If you visit (easier then via app) and login you’ll be able to see info on your zones.
Click on any zones which are part of your Flex Daily schedule, and you should see a “Soil Moisture” estimate, it ranges from 0% to 110%. Clicking this reading will bring up a detailed graph about measured gains (under irrigation & precipitation) and losses (Under evaporation).

Keep in mind that 0% does not mean that your zone is bone dry, rather it means that the zone has reached it’s allowed depletion threshold (found if you go to edit the zone & click “Advanced”). If the soil seems to have more water near 0% then you would like, you can increase your allowed depletion within advanced settings & thus extend the time until the next irrigation would be needed (zone would dry out more).

Also keep in mind that the moisture within the zone is capped at 110%, meaning any extra rain is treated as a runoff & not counted towards your totals, this may be different to other services.

TLDR: Adjust allowed depletion in case your earth seems to be still well watered at 0% moisture reading.
More on this here: Advanced Zone Settings (


Thanks for the informative reply. Obviously I have much to learn and will read up more. When I look at my zones, the current soil moisture ranges from 15% to 38%. These zones are set to 50% allowed depletion. If I understand what you are saying, I would expect the moisture level to get to 0%, or near, before another watering is scheduled?

Correct, Rachio will water on the day where available moisture would fall below 0%. If your root depth set to a shallow (low) number & allow depletion is low as well, it would result in frequent, short, watering.

Overall there are many different settings which would effect the frequency and duration of watering. Rachio does try to provide a starting point good for the majority of users, but, at the end of the day, each lawn is different. Feel free to share your settings and describe your lawn, there are many users within this community who could help you fine tune the best setup for your zone(s).

OK, so then I’m not understanding why Rachio wants to water today starting at 5:00p when my zone moisture levels are 15-38%. Seems like the system is wanting to water because the levels are below the 50% allowed depletion… If not, then something is broken. Or am I still not understanding?

Were the moisture levels going to go to 0% tomorrow if it didn’t water? If the “previous moisture balance” plus “precipitation” minus “crop evapotranspiration” is going to be zero or below, the system will water.

I guess I’m going to have to do my homework on this subject. I changed the AD to 5% on several zones and the soil moisture for those zones went to 0%. Changing AD to 75% yields soil moisture of 10%. 18% AD yields soil moisture of 43%. Doesn’t make sense, but obviously I don’t know enough. But for now setting a zone at 18% yields the highest soil moisture and therefore, I think, less frequent waterings…

Would be nice if you included the detailed moisture chart with each change. If you click on “Soil Moisture” reading, it will give you a detailed chart.

Since you are new to Rachio, I would recommend switching all your zones, but one, to a Fixed schedule and setting them to match your old controller’s schedule. Learn and experiment on the one zone you keep on Flex Daily. As you become comfortable with Rachio, you can start moving your other zones over to Flex.

I personally wouldn’t mess with AD too much…maybe plus or minus 10% at most…keep in mind, the percentages you are seeing are a sliding scale if you will. 0% in Rachio means that it is at AD (default 50%). If you adjust AD to anything else, 0% is still that AD setting.