Flex is OVER watering!

Gen 3 and Gen 2 controllers. Both set on Flex schedules. Number 1 problem - I have water running dow the street! Both systems are over watering. I have played around with the various advanced setting options but all to no avail!
Anyone out there that can tell me what I am doing wrong???

Thank you for your time.

We will need some background info, i.e. soil, climate, types of vegetation in the yard, etc. Also if you could post some screen shot of your advanced settings that would help as well.

South of Houston; hot and humid! Soil is mostly clay. St. Augustine grass on lawn, ornamental plants in beds. You will need to let me know if these images ‘load’.
Thank you for taking time to respond. This is Zone 1, if this works, then I can provide snapshots of other zones will same ‘over watering’ issues.

It was helpful for me to think about each zone like it was a bathtub in my yard. I hope if there are mistakes in this post people will suggest improvements, because I just came up with this on my own to help me understand my system and would like to know if I am off track. Basically you tell Rachio how much water the bathtub can hold, how fast water comes out of the filler spout when you are filling it, and how fast the water in the tub normally dries up. You mark a line in the tub that you never want the water to go below. Rachio Flex keeps track of the water in the tub, and refills it to the top every time it calculates the water must have dropped to the specified low water line. It adjusts the tub contents up if rain fills your tub, and adjusts down if it is hotter than normal.

If you start with an empty tub and assuming all your valves and pipes are not leaking or broken, if water was running down the street from your bathtub you would know that either it thought the tub was bigger than it really is, or the water from the spout was coming out faster than expected. If the estimate for how fast it dries up was too high it might think the tub was emptier than it really was and so it would overflow when it tried to refill to the top after several days.

You give it this information in the basic zone setup by telling it zone plant type, spray head type, soil type, sun exposure, and slope. These simplified choices result in specific values getting filled in for the detailed list shown in the Advanced settings page. You can see the results of your choices on that Advanced setting page and customize each value if you like.

In the advanced page, you tell it how much water the bathtub can hold by setting root(tub) depth and available water. You enter all this detailed info for one emitter of tub surface area, and for purposes of whole zone calculations you tell it how many total square feet in the zone. Available water is sort of like telling it how many rocks are already in the tub taking up space so the tub does not hold as much as you think it would based on the root(tub) depth. The low water line on the tub is set by allowed depletion level. The nozzle inches per hour tells it how fast the water comes out of the spout when refilling (assuming one such nozzle/emitter for each emitter coverage area for a tub of the specified depth). One way to think of efficiency is sort of like telling it how much water splashes out of the tub when it is being filled. Lower efficiency means the water is going to have to run longer to complete the refill (and could result in some of the oversplash running down the street). It is going to figure out how fast the tub dries out using daily evapotranspiration rates from a weather source, and crop coefficient tells it how much of that daily ET to consider for this specific zone/plant/sun situation.

To make sure your Flex schedule considers the latest details you have entered, you should probably uncheck the zone to exclude it from the Flex schedule, save the schedule, and then add it back when you make changes. If you look at zone run times under the flex schedule it will then show you how many minutes it thinks it needs to run (at the specified nozzle rate) to fill the zone tub to the top. If it starts empty, it will run long enough to fill the specified tub all the way from the bottom to the top. If it is a standard refill, it will only run long enough for it to fill from the low water mark to the top. (You can force it to assume it is starting full or empty but not in between.) It is not going to use the total square footage to determine the run time, it determines the run time for each emitter coverage area of tub surface area assuming there is a nozzle in each one and they are all going at the same time. It uses the total square footage you enter to report the total water usage for the zone for the number of minutes run once the run is complete. (I think default emitter coverage area for a drip emitter is a one-foot radius circle, but as long as you have consistent assumptions throughout for coverage area and total square footage I think this can be varied.)

To figure out why water is running down the street, you want to figure out whether it thinks the tub was empty when it was actually already completely or partially full, is bigger than it really is, or if the nozzle filling rate is actually higher than it thinks, or if it is refilling too often because it dries out more slowly than it expects, or possibly that the soil type, slope, and efficiency are implying that the water can be absorbed more quickly than it actually does. If all of these things are set at a reasonably accurate level the calculations do a very good job of keeping the tub properly topped up, although it may take some time to adjust to the pattern of longer run times that repeat less frequently (probably for both plants and people). There are some great resources in this forum and the help area that show you how raising and lowering values in the advanced settings will affect how often a zone needs to refill and how many minutes of run time it takes to refill it each time, which is really all the Flex schedule is doing.


Thank you, Zack. What does not make any sense to me is; it is asking for the total square footage of each zone, but does not ask how many heads there are in each zone… Without that, the math you suggestion would not work.

Hey @Ilangford, I’m here in The Woodlands so I understand the soil and the climate but unfortunately your image did not post. My native soil is different than the heavy black clay down your way so my settings aren’t going to help you. Are you using Flex Daily and do you have any restrictions on days you can water?

Yes, flex daily and no restrictions on days.

@Ilangford, try lowering your allowed depletion(mine is 35%). Also, you can lower your crop coefficient(mine is 55%). Don’t go crazy, just move them small amounts until you get it dialed in.

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@Ilangford, you can also adjust the times per each zone. Go under schedules-flex schedule-watering duration(here you can adjust each zone up and down).

Thank you for the hints!!! will give them a try!

I was also originally selecting clay, but changed to loam with clay after I looked up the soil in my area.


Thank you. I picked Clay thinking that would reduce the watering times as water runs off so much faster compared to Loam. Is my thinking wrong?

You don’t actually need to enter the real square footage or PR, if you know what you are trying to achieve. If left to its own devices it is using a per emitter calculation using assumed square footage for each emitter. There is a pretty helpful set of examples in an Excel sheet put together by another user. Good enough that Rachio linked to it in their Q&A. Here is the link: https://onedrive.live.com/download?cid=D4894A1463048060&resid=D4894A1463048060!140257&authkey=AA4LH1zjBeTQA34

There are three forms of the basic equation that are helpful, starting with assumption that you know the ACTUAL gallons per minute for the zone (either with a flow meter or by counting the number of emitters and knowing the real gpm(gph/60) for each emitter) - using 7.48 gallons per cubic foot. You can define a custom PR and square footage that results in your actual zone delivering the number of minutes you need to output the water needed by setting the values so that all of these equations hold true (as explained and illustrated in the Excel examples).
Area = GPM*((6012)/7.48)/NozzlePrecipRate
NozzlePrecipRate/(60*12/7.48) (this is what will be used to calculate water usage history)

their link to his work: