What is Efficiency?

The one parameter I have the most trouble understanding is Efficiency. The help link goes into a very complicated explanation, but never actually tells me what the numbers mean. It tells me to do a catch-cup test, but doesn’t explain why I want one, or how to enter the results into this slider.

So… What is efficiency? What does the two extremes, 100% and 0% represent? How can I estimate a reasonable value without a catch-cup test, and what are some simple observations I can do that will guide me in approximating?


The efficiency is a measure of how evenly your system delivers water to the entire lawn. I don’t see how you would be able to get to a pretty good approximation without a catch cup test. I guess if you notice there are some dead spots on your lawn you know that you probably have lower efficiency but I don’t know how would convert that to an actual number unless you monitor it as you tweak over the course of several weeks. Seems like a catch cup test would be less work at that point. To calculate the efficiency using the catch cup test you first do the test, take the average of the quarter of your cups that received the least amount of water (i.e. if you used 12 catch cups take the 3 catch cups that caught the least amount of water and average them) and divide them by the average of the total catch cups. Multiply this by 100 and you will get the number to put in that slider


What is 100% What is 0 ? How does changing this affect the schedule?

I believe 100% would mean you have a perfectly designed system where every square inch of your lawn receives the same exact amount of water. Don’t think that is possible. At the 0 end, I guess that would mean you have spots that receive absolutely no water.

Edited to add: Decreasing the efficiency will result in a longer watering time to ensure the parts that don’t receive as much water receive at least enough to survive.


A drip system is 100%.

No irrigation system at all is 0%

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That just causes even more questions, and makes less sense. My drip system is very hit & miss. But a drip system is 100% efficient? Then it doesn’t mean what I thought it means. (again)

I’m also very confused about what efficiency means when I have overlapping zones. I’m leaning towards setting each of these zones to 100% efficient, but it’s not clear at all that this is the right approach.

IMHO, this feature is not well thought out at all, and should be either re-designed or eliminated.

New Mexico State University has a comprehensive write-up on catch cup testing here. Number 11 in this write-up shows how distribution uniformity values (another way of saying efficiency) is calculated, and Table 2 shows the rating for sprinklñers used in turf irrigation, what is considered excellent down to poor.

And the instruction manual for the Orbit Catch Cups has a nice diagram and instructions for overlapping zones. You would still calculate the efficiency using the lowest 25% of the catch can readings in each zone.

If you don´t want to go through the refinement of doing your own catch cup test, I would just go with what Rachio has defaulted to.

well, a drip system is 100% efficient because a properly installed drip system will dribble water directly on the root ball, thsu EVERY ounce of water makes it to the target area.

what do you mean you rdrip system is very hit & miss.

so lets explain efficiency in a different way.

lets say my yard is a perfect square 30 x 30, and i put a single rotary head in the middle. this rotary that sprays 30 feet. so it will cover all of the yard except the corners.

so for example, the areas in red does not receive any water. so the efficiency is going to be fairly low here as we will have to water for a while to cause runoff to reach the red areas (the water will also travel subterranean to the dry areas as well).

i dont have time to do the math, but i think here we are ~60% efficient.

im not trying to be mean, but this is a concept that is very well thought out, you just do not understand it yet and i will try to help as best i cant. this efficiency setting is an industry standard for many years now.

you can also google this and find a lot of resources. since you do not understand it yet, the default of 80 should be fine.


@plainsane, Great diagram to show an example of efficiency!!! Duh! why didn’t I think of that??!!!

No offense taken. But a Rachio is a consumer product, sold directly to homeowners. One should not need a degree in turfgrass management to use it.

The fact that people seem to struggle to explain it proves its problematic.

Perhaps this feature is best moved to an ‘Advanced’ page. I’ve already suggested it should be dropped completely.

Thanks for the good explanation.

Question for you though - using your example with the red corners: If you lower the efficiency, it will increase watering times. How do these increased watering times help the red corners? Aren’t they still getting missed?

Then used a fixed schedule and none of this matters. Use a more efficient schedule like wan and very little of this matters. Use an expert mode schedule like flex and all of this matters.

If I recall efficiency is in the advanced zone setting in iOS so yea maybe the web page could use a bit of love, I don’t use it much, sorry @Dan, but it’s a nice backup when I’m in other countries.

Recommending to remove this feature Because you personaly find it confusing is like me asking any car manufacture to remove manual transmissions as an option to all auto buyers because I don’t understand how to use it. Why would you want to neuter my current success of cutting my yard maintenance cost in half using the wicked awesome feature called flex? I do not understand your method of reasoning.

by overwatering faster than the ground can absorb, the water spills over and runs off into these areas.

The water will also translocate underground via hydrostatic processes but in an echelon pattern.

Try to keep this in mind, Iro is a device of efficiency but before efficiencies can be achieved one needs enlightenment. Look at the switch to electrical power over steam in manufacturing. It was no more efficient. It took years before anybody realizes that the machines could be placed in different spots to increase efficacy and efficiency because they didn’t need to share a steam pipe.

I feel our current situation is very similar

Hey @ChicagoAndy. I’m just going to try to influence your perspective a bit by building on @plainsane 's analogy of the car:

1. Fixed (Fully automatic)

Hit start, take it out of park and go. Not as many people struggle.

2. As Needed (Semi-automatic / Paddle shift - Audi):

Same as above, but if you know when & how to shift the paddles at the right time, the extra control gives you a more optimal driving experience. If you make a mistake and shift too late or too early, there are some electronic failsafes in place.

3. Flex (Fully manual transmission)

Definitely takes more time to learn, more people struggle to do so! Now you have to get your left foot involved and figure out the tiny sweet spot for engaging & disengaging the clutch. You have to take your right hand off of the wheel and know when to use it to shift. Shift too early or too late and you risk a stall or worse yet engine damage. Boy, is it fun to drive and you have maximum control.

It sounds to me that the Rachio team might be giving us all three, or something equivalent. That way we users get to pick the option that we desire and have time for. The other point is that this has to be an insanely difficult problem to find a one-size-fits all solution for. I grew up in the Chicagoland area, and have spent the other half of my life here in the AZ desert. The weather & seasonal patterns, vegetation and temperature extremes between the two areas are worlds apart. Consider the rest of the US and add to it mother nature’s unpredictability, and imagine the algorithms required to make a one-size-fits all solution with minimal user input ?

Anyhow, good luck with your continued exploration of the setup. Looking forward to a Cubs/Sox World Series!

  1. Fixed. Same as my Hunter Pro-C I just replaced. If that’s the best that Rachio can do, then there’s no point.

  2. As Needed. A broken product that is not fit for sale and illegal to use in most of the country. Puts customers at risk of very large fines.

  3. Flex : The only functional mode that does more than a Hunter Pro C. The only reason I haven’t returned it for a refund.

Look, I get it. This stuff can be complicated. But look at Nest, or Sonos, Amazon Echo, or even Insteon - SmartHome products that seamlessly hide the complexity and are just plain easy to use. You don’t need to be an electrician to use Insteon, or an audio engineer to use Sonos, or an HVAC technician to setup a Nest. They’re excellent, out of the box products that just work well.

I really hope Rachio “gets it”, because this could be a very cool device. But so far, you seem to need an agriculture degree to use the only mode that’s actually functional. Not a good sign.

It already is in my opinion and It will get better.


Dude, seriously? To the product team, this guy doesn’t speak for me.

Comparing Rachio to Nest is like comparing a Tesla to my kid’s Radio Flyer. There are way more variables to consider than just temperature.

I don’t have an agriculture degree. I do have a willingness to learn how to improve the quality of my lawn/landscaping and Rachio has helped me tremendously. The product isn’t perfect, but through unprecedented community outreach they have proven over and over that they are willing to listen to their customers.

Meanwhile, Nest users are still fuming that the thermostat still doesn’t display current temp in large print after 3 HW revisions and the Smartthings community is is open revolt.

If you want complete automation without having to acquire any knowledge, I suggest you contract with an irrigation maintenance company. Otherwise, do some light reading on the FAQ page and ask constructive questions here. You might be surprised how quickly things start to make sense.


The tone of your reply is entirely unhelpful.

Good technology should be indistinguishable from magic. Other companies seem to get this. If the best suggestion is to tell the users they need to learn more, then you’ve shooting at the wrong target.

Thanks for giving me another reason to pull out my Arthur C Clark reference book:

“When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

@ChicagoAndy @johnny2678 What a great thread and shows our conundrum we have at times.

How to take advanced topics like root zone depth, efficiency, available water capacity, moisture levels, etc. and condense them into simple software that works for the majority of people. IMHO the most important part of our system is the input data, which includes all of the zone characteristics (including accurate precipitation rates for nozzles) as well as accurate weather data. Each one of these pieces is an important component into our scheduling algorithms, and if any one of them is way off, the end results might be less than ideal.

Know that we will continue to move in the right direction and will build more things into the software to help people choose the right zone characteristics as well as getting more highly localized weather data.

Please keep these respectful discussions coming! They will ultimately help us continue to build great products.

:cheers: :colorado:


Thanks @franz, I do have a couple of wacky suggestions on user assistance and I’d be curious to hear your feedback.

Moving this to a new thread under Product Suggestions.

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