As tmcgahey said, the amount of sun or shade is taken into account for the ET setting. Set up two identical zones, one in full shade, the other in full sun, you will find a difference in the ET setting (only)
That’s actually a great idea. It would lower the efficiency, but put more water where you want it and less elsewhere. It might overcompensate in cloudy weather, but it does sound like something worth doing.
Could you explain what you mean by “lower the efficiency”?
Yeah, I knew I should have said more about it. In the Rachio Advanced settings for each zone is an Efficiency setting. Normally, I would have expected say a 70% efficiency to mean that 70% of the water gets to the lawn, with 30% lost due to evaporation, but that’s not the case here. Efficiency is defined by the Catch Cup formulas, and is the average flow of the lowest 1/4 of the cups measured in a zone divided by the average flow of all the cups. Then there’s a more complicated formula that adds more time to the zone’s irrigation to help compensate for the low efficiency (by overwatering the rest to help out the lowest). Normally, a high efficiency is desired, saving water and giving a more even watering result on the lawn.
If, as was suggested, higher water flow heads are placed in sunny areas, and lower in shaded areas, you are actually /creating/ differences in the water application, lowering the efficiency. Normally a bad thing, but in this case you’re doing it on purpose, so not a bad thing.
Hope this helps.
Can I just check something with you experts - how do connected rain sensors work with the Rachio3 ? Do they cause the controller to ignore the rain from a PWS or does it co-exist with one ? Does on improve the decision making of the controller ?
He called us experts! 
You can wire a rain sensor into Rachio by connecting to the sensor ports (wiring varies slightly by make/model), and letting Rachio know it is there in the settings. When the sensor shows rain, it basically puts the system in a standby mode until the sensor dries out, and normal watering continues, but it doesn’t really change the way it waters. It can work in conjunction with PWS to give you better accuracy of rainfall at your house, rather than a PWS down the street. Just make sure you maintain it…
Thanks for that. I didn’t want to rely on some 3rd party to provide our data, so we installed our own PWS. Our next nearest was about 2km away and higher, and I have seen decent differences in the weather recorded,
He ought to be playing at the Comedy Club! 
Well in all honesty, you guys are. You have a deep understanding of the options and advanced settings and know how the system behaves (through personal experience and logic and knowledge). I bet there hasn’t been a single post on here which has defied all logic. It seems to me that there is always a good reason for the controllers’ behaviour in all situations, with unexpected behaviour due to user misconfiguration due to misunderstanding, or due to 3rd party PWS’s being either offline or spitting out errorous or unexpected data.
Just getting to read this thread today and wanted to add my two cents on PWS’s (I’m away from home for a month babysitting a new grandchild). I installed my own PWS so that I could keep track of things a little better. Occasionally it starts recording a precipitation for the day of 83886.07 inches. I had it working fine, left for
Texas, and a day later it started recording this again! All the every few minute recordings of precipitation on WeatherUnderground are correct, it’s just the daily totals that get changed to 83886.07, and that is what Rachio uses. So I had to change to another PWS until I get back home. This is something that Rachio can’t pick up, as it looks to Rachio like the weather station is working correctly. So, @garyjnj1, something funky may have happened to the weather station that worked so well for you these past years. Just glad to see that you are starting to make some progress.
But the rain sensor should change the way it waters. My Rain Bird water sensor has an inches of water setting that can be used to set how much precipitation is allowed before it activates. Rachio should be able to allow users to input that value so that whenever it triggers at a minimum, it knows that the soil received that much water. It can then compare that value with the value reported by the weather station and throw out the lower of the two values. Sort of like using the sensor as a check and balance to the reporting weather station value. This should be a configurable (off/on) feature.
A bug I noticed today is that if a program is running and you disable the zone in the program, the disabled zone does not get removed from the already running program. You have wait until the the program gets to that zone that was disabled and manually skip it each time that zone starts.
I disabled my zone 5 and 6 and Rachio did not remove it from the already running schedule. So I had to wait until any desired zones completed for it to get to the undesired zones and force the skip:
Irrigation Page(5/6 disabled)
Up Next Schedule Page still has deleted zones
Zones Run Anyway
Hi Linn, thanks for sharing. Think about it for a moment, if Rachio receives a 83k" reading from a PWS, wouldn’t it be logical and reasonable to code the software to flag such and anomoly, toss that number out, and alert you? Or, perhaps allow you to choose what happens via push notification (e.g., check the nearest viable site that has three reasonable readings or fall back to the nearest approved site, or do nothing). That value would equal mass flooding from the Nile River. LOL.
Your scenario is a perfect case scenario. Away from home, relying on your Rachio and PWS to report accurately. Of the two, Rachio is the brain and it should not require daily monitoring like your new grandchild (which is pretty much what I’ve had to do with my device).
Had you not caught that, Rachio would not have watered for the duration of your stay. If in a hot area of the country that could equal severe stress or damage on your foliage.
But yes, I am definitely making progress.
Or at least place an order with Lowe’s for material for the arc you should be building. 
This just sounds dismissive to me. Thanks for the help.
So where would I begin to set this up then? Using Flex Daily, it consistently underwaters my spray zones and overwaters my drip (when first set up, on a system with 4GPH emitters for 2 trees, it defaulted to a FIVE HOUR runtime).
Not dismissive at all. Just pointing out that you don’t need to use the Flex Daily schedule - that you can use other options that don’t require as much time or energy to set up.
Brien, considering that there is no place to input pipe diameter, number of spray heads, sprinkler pattern(triangle vs box), it should probably come with a catch-up kit and instructions on how to place them and set it up the device based on that test.
Would also be very useful to have a drop down menu with the top 10 spray head devices (e.g., Rainbird 5000) to choose from and default values built in.
This would make it easier for it “to just work.”
The “tuning” required to get a Flex Daily schedule dialed in involve mainly the Zone Advanced settings. The first link below describes the different advanced settings and how they work. The second link below is a user describing what he did to dial in the settings for his yard.
LAST UPDATE:JAN 14 2021 1:04PM • EST. READ TIME:EST. READ TIME: 6 MIN
Advanced Zone Settings are primarily used for Rachio’s “Flex” Scheduling. If you’re using Flex (Monthly / Daily) scheduling, the Rachio controller calculates your watering similar to that of balancing a checkbook. The plant’s soil water storage reservoir is like that of a bank vault.
However, this reservoir can only hold a limited amount of water that is useful for the crop. If you overwater the soil reservoir, it will result in water loss due to deep percolation and/or runoff losses. The turf/crop evapotranspiration (ET), or water loss & use, is the crop’s daily water withdrawal. Irrigation and effective precipitation (aka rain) are deposits to this “bank account”.
When you select a zone within the “Irrigation” tab, you’ll see the Zone Details page. To edit your Advanced Zone Settings, select “Edit” and then scroll down to select “Advanced.” Here, there are thousands of unique configurations possible based upon the characteristics of your lawn. After creating or updating a zone, default values will be assigned accordingly based upon the zone attributes. We recommend that only experienced Water Managers adjust these settings; however, the “RESET TO DEFAULT” button at the bottom of the page will reset the Advanced Zone Settings to those based upon the zone attributes of each zone.
Remember to save your edits! To do so, tap on the “Done” button at the bottom of the Advanced Zones Settings page.
The area is the size of the chosen zone.
Available Water (AW) or A va ilable Water Capacity (AWC) is the range of available water that can be stored in soil and be available for growing crops. The AW of soil is related to texture and structure, the spongier the soil the more water it can hold. Typical AW holding capacities represent the amount of water that can be held in an inch of soil; in short, how much water can be available for plants with the depth of the root zone is known.
Root Depth (RZ) is the soil depth from which a plant extracts most of its water needs. The RZ is equal to effective rooting depth and is expressed in inches within the Rachio software. To determine the depth of the RZ, a soil sample containing the roots must be taken. It is recommended to use a soil probe to minimize disturbance of the soil and to obtain a good quality sample. Once the core is removed from the probe, look for the small roots to determine the number of inches from the top of the core to the deepest root near the bottom of the core. This sampling process should be done in several locations throughout the test area to determine an average depth.
Allowed Depletion (AD) is the maximum amount of Plant Available Water (PAW) allowed to be removed (expressed as a percentage) from the soil before an irrigation refill occurs. PAW is the total amount of water held in the plant root zone based on Soil Type and Plant Root Depth. Increased surface evaporation (loss) of water and usually higher rates of transpiration are associated with frequent irrigation events; It is best to irrigate only when the root zone has reached the AD threshold.
AD represents a management decision to use the water that is most readily available to the plant. While plants can still extract water from the less available water reserves, the plant will begin to show signs of stress or wilt.
In short, AD is the quantity of water that is easily used by the plants from soil moisture without withdrawing all of the water prior to refilling the soil profile. Additionally, by allowing the soil to dry down, it draws air into the root zone. Roots use this air to breathe & grow; having the appropriate amount of water and air in the soil allows the microorganisms to flourish, enabling the plant (& soil) to be healthy.
Efficiency (DU), also referred to as Application Efficiency or Distribution Uniformity (DU), tells us how efficient the water is being distributed by the sprinklers. The lower the DU, the higher the run time needs to be to deliver enough water to the area with the weakest coverage.
Above: Watch this quick video for tips on determining the distribution rate of your yard.
If the E/DU is below 0.40, then time and effort should be spent identifying what needs to be done to assure the system is operating optimally. This may include recommendations for improving maintenance or to seek the services of a certified Water Manager to identify the factors that are causing such poor performance. When the uniformity is low, it is hard to justify the amount of additional water needed to minimize stressed areas and achieve an acceptable appearance. When additional minutes of run time become excessive, runoff potential increases, and it becomes more difficult to do proper maintenance if the sprinkler system is operating beyond its desired or designated water window
I don’t understand why Flex Daily gets such a bad rap “for being complicated”. Or maybe put another way, I don’t understand why Flex Monthly, or even Fixed, don’t get the same bad rap. ALL the same regular settings and Advanced values are used with Flex Monthly and Fixed. Even Fixed calculates a time to water based on the other settings, and watering with Flex Monthly comes up with settings in the same way, except it uses “Average” weather rather than “Actual” weather, and considers whether it’s rained or not rather than actual rain.
There are the same number of settings on both. And if you screw up the Nozzle Inches per Hour, it’s just as problematic with any schedule. OTOH, at least Rachio calculates all the settings based on information you give it, and you don’t need to guess how long to water to at least get close.
@rraisley I think that with the Flex Monthly and Fixed people end up adjusting the duration times so that it matches or is similar to what they did with their old controllers and ignore all the settings. You can’t ignore the settings as easily with a Flex Daily schedule.
I used a Flex monthly for about 2 months before moving to a Flex Daily and for me the key to using the Flex Daily was figuring out the nozzle inches per hour. I found it pretty easy to calculate using my water meter and the area of each zone.
I agree with that, especially with Fixed.
You kinda can, but need to choose a “typical” weather time, which is tougher.
Absolutely agree with that. But if you don’t properly calculate the Nozzle Inches per Hour with Flex Monthly, and use the recommended settings, it can be off just as much.
