Flex schedule seems like too much watering?!

Okay so my meter man came and I’m in a new month of pricing so I let the Flex Schedule rip. I’m a bit paranoid about another huge water bill so I’m watching this thing like a hawk.

Hand typing what the Flex schedule says today that it is doing and will do over the next two weeks looks like this:

That two weeks and >26K gallons is going to cost me $227 - if it repeats the same thing the following two weeks it gets worse because now I’m moving into exponential pricing. My bill for August would be $914 for 52K gallons (7K CF) of water.

Oddly enough it waters Zone 1 once in two weeks.

I’ll watch the soil but it seems like the depletion rate is being calculated as higher than it will be actually - probably based on the variables I typed in. I measured GPM at the meter for each zone, built custom nozzles per zone, and hand measured the square footage.

It feels high because I had my irrigation system nearly shut off for about two weeks and the grass is still green. However, the weather is predicted to be pretty hot.

Fri 93/61
Sat 91/57
Sun 88/59
Mon 81/57
Tue 77/57

Weather Station: PWS_DRAGONKP 1.63

Any suggestions on how I can check the soil and change some variables so the ET becomes more accurate?

This seems like quite a lot - been running from 4 AM to just past 7 PM. 678 minutes in a day - I guess I really need to move my start time back? This was watering all day during 91 degree weather - which seems sub optimal.

Now it recalculated and intends to water for another 7 hours and 40 minutes tomorrow 8/1 (unlike the schedule above). That is too much - I put in a rain delay. (note - this is because Iro thinks the zone is still is depleted and, in reality, there are puddles of water on the surface).

@brian, thanks for putting together this comprehensive spreadsheet to monitor your Flex schedule. Please keep in mind that your Flex schedule is subject to change on a daily basis given the weather data it receives from your preferred weather station.

The best way to monitor your Flex schedule is to use the Moisture Level graphs, available in the web app: http://support.rachio.com/article/395-understanding-moisture-level-for-your-zones

Each zone will trend differently per it’s configuration. The biggest inputs to Flex are recorded in the Moisture Level graphs so you can see exactly what the Iro is doing and why.

Did you double check each zone’s efficiency (distribution uniformity), this plays a key role in how long each zone waters for. I’d recommend reviewing this post for tips on conducting a catch cup test: Negative Impact of Manually Watering on a Flex Scheduled Zone - #40 by emil

Have you reviewed the predicted watering schedule using a different weather station? PWS can vary in the data accuracy collected. I’d recommend selecting a NWS (national weather station), which start with the letter “K”, followed by 3 letters (4 letters total), to compare how the schedules differ. NWS usually do a better job of calculating ET, but might not have the best precip data if you live in a micro climate.

Yes, we default to a 5a start time.

I’d highly recommend doing the following:

  1. Try 2-3 other weather stations. See if the station changes
  2. Perform a catch cup test and further dial in your system
  3. Review this support article to fine tune/override your flex schedules: http://support.rachio.com/article/385-flex-schedule-tips. Below is a summary of the adjustment options:

Hope this helps :slight_smile:

Best, Emil

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Thanks for the discussion here - it was very helpful. I’m having to watch my water usage closely too here in S. California and the flex schedule was doubling the amount I normally water. My grass does just fine this time of year with an every-other day schedule @ 30 minutes per zone, but my flex has been watering it for over 30 minutes every night for the last two nights. I keep thinking it will adjust and not water, but it says it will water again tonight. I took the grass off the flex until I can tinker with it more and left my slope and fruit tree areas on flex to see how they do. Since we’re always having to watch our water use, I think we’re just used to our lawns looking green but maybe not as green as the Iro likes!

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If you want to do some flex fine tuning this might help.

This explains a few dials to modify watering duration and frequency.



I like that tips page, it answers many questions I had except one. Does the water drop adjustment impact frequency? For example if I pick the option below normal/default, to use less water, will that increase the frequency?

Not currently, it only adjusts the watering time. In a next release, we will be providing a similar adjustment for frequency so that you don’t have to learn (unless you want to!) about MAD, etc. I want to make adjusting as easy as possible and provide more abstraction.

For now, if you have the correct crop and soil type chosen, I’d say the easiest way to affect frequency is either ‘Allowed Depletion’ (Advanced Zone settings) or Sun exposure.


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Thank you so much for the responses - I hope this helps more than just me. :smile:


I understand that the Flex Schedule changes - that’s why I like it! After looking at the Moisture Levels it appears that Iro thinks the soil is not at 100% saturation yet - I disagree. My hypothesis is that I hooked it up and didn’t run it (water prices) so Iro believed all my zones were completely depleted (although I think this still points to a depletion discrepancy as root cause :wink:) .

If I had those “moisture control add/subtract” controls I’d put the soil at 120% from yesterday’s watering and see what it does then.

These are great - can’t wait to be able to modify the moisture level. It seems like the Iro is off-track and adding moisture to each zone will make it get back on track.

I thought I was getting a pretty accurate set up by measuring CF at the meter for each zone running 2 minutes and hand measuring square footage. From that I created a custom nozzle per zone with my calculated PR. Are you saying I should also or instead order catch cups and do a catch cup test?

I switched away from the NWS because it is >15 miles away. I watched the one I have selected and the data seems pretty accurate (especially precip) and it was a brand that was reported as more reliable with less errors on here (Davis Vantage Pro 2). I can’t see any ET data on the PWS site for my local station. Does that mean I’m not getting the proper ET values from this station?


  1. I’d prefer to use that close PWS but for the sake of trying something new I’ll switch to the ~15 mile away one.
  2. Would like to understand a little more on how this is more accurate than what I did with the meter and custom nozzles.
  3. I will play with these and check soil moisture to attempt to get the Moisture Level to match what I’m observing. That seems to be the key to getting the Flex to be more appropriate.

@brian, please excuse my delayed reply. Have you had a chance to check out the soil moisture adjustment feature we recently added? It allows you to recalibrate a zone’s moisture balance to completely full or empty with a click of the mouse. Your Flex schedule will adjust the next day to compensate for the adjustment.

Yes, I’d recommend doing one once a season to check your system’s efficiency. There’s a big difference between the water output and the distribution uniformity (efficiency) of said zone. The lower the distribution uniformity, the more water the system has to apply to the lawn. The meter method you used only told us how much water was used, but not how effectively.

You should be. I’d recommend logging into your soil moisture graph(s) (now available on mobile!) > select the drop down for “more detail” > then look for “Crop Evapotranspiration (-)” > this will show you how much moisture the crop is loosing from evaporation on a daily basis.

Hope this helps. Let me know if you have any other questions.

Best, Emil