One thing I’ll note with regards to single point emitters vs. drip rings, The choice isn’t related to laziness or lack of knowledge I believe. I’ve gone to several seminars put on by landscape experts in the valley that seem pretty knowledgeable. They mentioned drip lines but always focused on single point emitters. I believe this is because most of this is pushing for desert adapted landscapes. So you don’t necessarily need a drip ring since for most desert adapted trees you don’t need to water more than 50% of the root ball for the tree to grow.per their recommendations. So a drip ring may be overkill and also a bit of a hassle since you do have to keep moving the emitters out to the drip line as the tree grows.
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Which even further complicates a solution. Here in the south we do a ring then apply the emitters where you want them.
We need a GPM based upon meter readings to have an actual minute usage for each zone. This should have been done first because it is way easier and user friendly than a complicated dripper/area calculation.
We need it soon!
@Commuterfisher, are you referring to a GPM field in the app? If so, I’d recommend adding some comments to this product suggestion in how you’d like to see it work.
If you’re just looking for a calculator, the steps listed in a post above can be used to calculate the precip rate using your meter (see meter instructions within the interactive questionnaire for more detail).
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@lucasc For your online calculator that determines precipitation rate of drip emitters, would the 1 sq ft assumption increase with the number of emitters in the zone? I have about 15 drip emitters and they put out in total 50 in/hr from your calculator (my system is a bit over-pressured) ! Should the assumption be 1 sq ft per emitter? So my square footage would be 15 sq ft to bring the precipitation rate down to 3.3 in/hr?
@redwagon If you use the 1 sq. ft. assumption, do a sanity check on your run times once you use the associated PR. I found the watering duration to be vastly lower than what it should be using the 1 sq. ft. assumption for single point emitters. I know the 1 sq. ft. assumptions work for some. Maybe it’s due to desert watering requirements, but I would check your watering times against what you expect them to be. My PR for my 2 GPH drips (3 per tree) is 0.4 in/hr to get the deep watering we require. At 3.3 in/hr my run times would be 8 times shorter than the local (Arizona) recommendation for my trees.
Thank you @azdavidr, just wanted to highlight the error in the online calculator that is assuming 100% of the water in a drip zone is being applied to only 1 sq ft of area. Most drip zones have multiple emitters. Reading through this thread, I understand the arguments for/against 1 sq ft usage, but that area should at least be per emitter in the calculator.
Interesting that you went to 0.4in/hr to get the watering you need with the 2 GPH. I’ve figured out that mine is mostly 1 GPH single point emitters, and I had to go to 0.2 in/hr to get the watering that Water Use It Wisely recommended. I’m not in the desert, but I had been doing 130% of the time to get the watering time that it seemed the plants needed, not scientifically at all, but just based on watching them and how they responded to the water - I had started with 0.5 in/hr when I set the system up (which watered WAY too short - and I had to go to 150% to get to what the plants seemed to like better), then went down to 0.3 in/hr, and after reading through Water Use It Wisely, I’m now down to 0.2 in/hr and I’ve been able to remove the +/- amount and let flex daily do it’s thing.
BTW, the PR = (96.25 (AB))/C calculation made no sense to me with emitters. Assume C=1. I haven’t exactly counted all my emitters, but if I go with 75 1GPH emitters, I come up with 96.25 (75(1/60))=120 in/hr, And if I have 100 of them it’s 96.25 (100*(1/60))=160 in/hr. Neither one of them puts me anywhere NEAR the 0.2 in/hr that appears to be working fairly well! So thank you to @redwagon for getting me to understand that I probably need to make C equal to the number of emitters. So even doing that, I still come up with 1.6 in/hr which would still not get me enough watering time.
Hopefully someone more knowledgeable than I can come up with a formula that works for emitters! At least I was able to back into it using the Water Use It Wisely site. (Yes, I know I can go out and read the meter and it will probably be more accurate, but my meter reads in cubic feet which means yet MORE calculations, albeit easy (1 cubic foot = 7.48052 gallons) - I was just hoping for a simple mathematical way to do it).
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If you are doing this by hand, I found 1 square foot per gallon per hour works best, your mileage may vary
to assume total square footage is 1 makes no sense to me
It should be (96.25 * (75 /60)) / 75 = 1.6 inches an hour.
But this method assumes you ring your vegetation, aka you have multiple emitters per plant.
If you don’t, you need to calculate the square footage of every bush canopy and use that as square footage.
But again this path will be fraught with perils of you are not ringing your vegetation.
Software can only accommodate a certain amount of negligence 
Even the beloved water wisely site recommends the ring for each plant so if you are not fin plowing that, you need to fall back to square feet of canopy as the area of this equation
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I want it to come up in my application everyday the actual amount of gallons used. This hand calculation is in exact and way beneath such a nice app as yours. I don’t get why you have not made this more user friendly yesterday.
Please make this a priority. Today.
I agree there should be a drip option when setting up the schedule. That is a badly needed addition. I’m actually not a fan of drip irrigation because I’ve seen so many drip installs here that are an absolute mess. But for the more arid western states where drip is so prevalent it is a must to have drip as an irrigation.
Not sure that you live in the desert and use drip extensively. All the water landscape courses teach a method of matching gph to the size of the plant and yes you sometimes have more than one emitter per plant, and then you set the time based on the gph and what is needed for a plant with that size of canopy for that season. All the other calculations are just confusing and have nothing to do with it. By definition a xeroscape watering system concentrates the water only on the plants, not the area - so that just confuses things. You are deliberately not watering the area, but rather just the plant to minimize evaporation and not waste water where you want nothing to grow.
I agree I’m mystified why Rachio will not embrace emitters more fully. Much of the water limited West operates on these principles.
i dont live in a desert, but i use drip to cover 7,000 feet of vegetation so i have a lot of experience.
all in all, i think you just summed up why there is not a solution at this time.
because you are viewing the situation from a single dimension. they could just lay a few boxes into a ui to get the water estimates correct but it will do absolutely NOTHING for a flex schedule. so what everybody is seeing right now is PROPER software design. dont build a house of cards to tactically squash orthogonal user complaints…build a proper scientific computation.
everybody is conflating rachio’s willingness with proper scientific discipline.
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Doesn’t it depend on implementation? If they took a user-input the gallon displacement number and back calculated a pr that would put out that many gallons, the rest of the algorithm stays the same and flex still does it’s magic. That’s what us desert folk are doing manually right now, and it works great. It’s just figuring out the pr value that’s the confusing part IMHO.
Can you write out the formula? Because I’m missing something. Take your rig and work backwards from their to get what you think your pr is using only gallons, no area
I’m not desert, just Dante’s garden, but I agre with you. Once I backed into what I think is a relatively good PR value, flex daily seems to be working pretty well (outside of my issue with rain predictions that don’t come to fruition, but that’s a totally different problem). It’s figuring out that PR that is hard.
@plainsane I think the confusion is that there is no intent to change the total inches displaced by the Rachio software in it’s calculations. This is just a way to take area out of the process of calculating the PR for a single point emitter, or a few multi-point emitters, when you know how many gallons that you want displaced. Whether you deliver those gallons from 1 emitter or a tree ring becomes inconsequential to the software. Of course as you point out it is certainly better for your vegetation to have a nice ring! I posted a manual procedure here:
Quick Question: What are your AW settings currently at, relative to your Area in “advanced settings?”
Just got Rachio installed recently and I’m trying to dial in my drip line system now … seeing these monster watering times scares me a little…slowly studying all of this to become an official soil engineer, but for now I’d like some feedback to hopefully take advantage of the features we’ve paid for…I think I’m close…
Welcome to the community @rrubino. I’m not sure I understand the question. The AW (Available Water) and Area are completely unrelated parameters. If you haven’t found these two links, I recommend giving them a read to see if they help with what you’re trying to do.
1st - Dialing in your soil:
2nd - Dialing in your drip:
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