Exact water usage using flow


I hope this involves an etch a sketch throw back :wink:


Now that I’ve been working it for a few months I think it would be great if there were a system that was entirely different for drip irrigation setups. Otherwise the statistics are useless.

Since we can generally tell how much water is coming from any given emitter, and we know how many emitters are on each zone, it would be great if there were a calculation system that could accurately accommodate that.


A gpm input per zone would make life pretty dang easy…juuuuuuust saying :wink:


Ya, I apologize, we just haven’t had time to build this :cry:



@rickandersonaia & @basher519, I know the product team has been discussing simplifying zone setup. You can use your water meter to fine tune your nozzle’s precipitation rate by using this equation:

PR = ((96.25(A)/C)

96.25 = constant that converts gallons per minute (GPM) to inches per hour. It is derived from 60 minutes per hour divided by 7.48 gallons
per cubic foot. times 12 inches per foot.
A = gallons from water meter
C = zone square footage


I would think this feature would be a higher priority for the rachio development team as this feature would be used to greatly improve the estimated water used/saved per cycle. This would not only improve the data to each user, but it would greatly improve their water usage data as a whole. I would be willing to guess that the “Community Savings” number currently has a large margin of error because you cannot vouch to whether or not each user’s data is correct. Not every user is going to modify the actual square footage of their zones in the advanced features, so i feel the numbers could be grossly incorrect. My system uses around 1600 gallons per cycle, but the first time a cycle ran using my Rachio, the app reported that I used twice as much as what I actually used (this was before I changed the square footage of my zones). If my water estimates are this far off using the default settings, imagine how inaccurate the water used/savings statistics are for the “community savings” as a whole.

Implementing a GPM per zone input would greatly improve the accuracy of the gallons used and saved as well as making the “community savings” estimates much more accurate. We all strive for more accurate information and I feel this feature would greatly help to make the water usage and savings statistics much more accurate for everyone.


For those that have their precipitation rate (inches/hr) and their GPM usage from the meter and need to figure out the square footage so the app shows the correct water usage, i did some simple algebra and converted the Precipitation rate formula so you can easily calculate square footage you need to put in the app:

I have created a quick spreadsheet in google docs to help those who dont feel like pulling out the trusty calculator to do the math for each zone. Download your own copy of the spreadsheet to do the calculations (the formula is already in the Square Footage Column, so simply enter your precip rate and GPM and it will do the math for you): https://drive.google.com/open?id=1danaMKyuma94IY0DN_wJs0DIu_gGgLWf8Fa0k2StKCU

I dont know why this isnt a calculator on their support page. If GPM manual entry is not going to be in the app, then at least put it on the website so users can easily find the way to make the calculations themselves.


Thanks for the formula…It’s just what I needed. I know my PR of my nozzles and GPM from observing my service meter, all I needed was the formula to get sq ft so I can get some accurate water usage statistics.


I would make it a wizard where you:

  1. Go to your meter
  2. Start the wizard
  3. Rachio turns on first station
  4. You press a button after a set number of gallons or cubic feet go through
  5. Rachio stops the station and waits a few seconds, then turns on the next station
  6. Repeat until all stations are complete.

Rachio calculates gallon/min on each station and you enter the square footage of lawn and ground cover of each station…


What a brilliant solution!

@emil is this possible to deploy?

It would really improve accuracy of real water usage for users. And it would allow team radio to collect better aggregate meta data too.


That’s it. So easy in app field for each zone! I was also looking for water leaks and checking my meter and thought of this. So easy. Too simple for programers. They like to make life complicated.


After using my Gen 1 for nearly two seasons and actively following and participating on this post I think that we actually need two different items:

  1. PR as it’s currently programmed, don’t change anything. Users would use catch cups to accurately measure the amount of water hitting their lawn and Rachio uses this value to compute watering times as it currently does.
  2. Actual water usage. Users would input actual GPM per zone by reading their water meter and Rachio would show total water used for watering based on the input GPM and the amount of time the system watered for. This item would not be used for any watering calculations, purely information.

The problem I’m having is that I’ve got a lot of poorly designed zones, for example a small (~100 ft2) zone with 6 heads that in total run about 10 gpm. When I run the hand calc to back out PR I get a huge, unrealistic number (due to the poor design a lot of the water misses the grass, very narrow, long strip) If I then use this number for zone PR I’ve gotten the usage data on Rachio very close to exactly matching my actual water meter usage, however, because the PR is so high the algorithm spits out ridiculously low watering times which I then have to adjust. I know I can play with the efficiency setting but it takes a lot of time to go back and forth making small changes, creating new schedules, etc. just to see that the adjustment on the scale wasn’t enough or was too much.

If you input actual PR via catch cup test and actual flow rate per zone, in theory Rachio could accurately calculate correct watering times without having to guess at efficiency so much as well as accurately calculate the amount of water used. You could even ‘guilt’ people into fixing their inefficient systems, for example: “Your watering cycle today used 868 gallons of water, 502 gallons went into you lawn and 366 went to the street/sidewalk and then down the drain, based on water prices in your area you put $X down the drain”…

Just a quick thought… It seems like I can get good calculated watering times OR accurate usage information using the information in this post but I’ve yet to find a way to get both. Simply adding an input for GPM in place of PR will not solve that problem.


If you have an accurate pr and an accurate square footage, the number comes out close enough to reality to ignore the descrepency.

If you are looking for hyper accurate water accounting I suggest a flow sensor. That is what I did, it’s fantastic


I’d say it depends on one’s irrigation setup and your personal definition of close enough. I certainly can see that with an efficient irrigation system this would be the case. Some of my zones do come pretty close but a few don’t because of the installation. It seems like this thread has centered on getting Rachio to show accurate usage information. It’s been my experience that with poorly designed zones I can’t use true PR (found using catch cups) and get the usage anywhere near the actual number. Forcing Rachio into calculating accurate usage by using actual flowrate to calculate PR screws up the watering times.

I’m definitely a ‘hyper accuracy’ guy, why? no idea and it drives my wife crazy. I ended up integrating my water meter with HS3 Pro and never looked back. Another user developed a Rachio plugin for HS3 so I can track/trend/etc. all of the data to my hearts content on that software. Iro was the first IoT device I purchased, downward spiral from there and now it’s just one of many ‘toys’ all tied together with HomeSeer… Personally I’m happy with my current set-up and really don’t have a ‘need’ for a GPM input like I thought I once did.



i would like to understand why this would not line up. it seems to me either the square footage of the zone is off, the pr is off or the efficiency is off.

i agree it is a pain in the butt, but unless someone is willing to install a flow sensor, a gpm setting is not that friendly either. each head pattern in the hard will have a different flow rate, so you are still stuck with a bunch of math either way.


My worst zone is 108 ft^2, it’s a long narrow piece or grass between the sidewalk and street and the irrigation installer did not design the most efficient zone. Per my meter the zone uses 8.1 gpm, backing out the PR from that gives you 7.2 in/hr which is far higher than what my lawn actually gets measured from catch cups (1.6 in/hr). If I set the PR for this zone to 7.2 the usage information is very accurate, however, the default watering times are way off. They’re too short because the systems uses 7.2 in/hour to calculate the times (among other variables).

Caveat - the above information assumes I don’t mess with the efficiency and leave it at or near 100. You’re right, given the poor design the efficiency is way off. Through trial and error I’ve found the actual efficiency to be closer to 54% and then everything works out.

There are a lot of variables you can play with as you’re all well aware. My whole point is that simply adding a gpm input for more accurate usage data will likely cause you to have to mess with other variables, like efficiency, to get the calculated watering times in the ballpark, depending on your unique system/installation. In my experience it’s a bit time consuming to move the sliders, create new schedules, see how things changed and repeat as necessary. I’d like to input the variables of my yard, as precise as I can measure/determine them, and have the iro spit out ‘good’ numbers (usage, time, frequency). If you use an accurately measured PR for the watering calculations and then a ‘dumb’ usage variable in GPM you could easily get accurate usage information without having to tweak other variables.

Worth noting that it’s very nice that they’ve provided so many tweaks because no two systems are alike and I love the flexibility, just a pain to use.


To get both accurate PR and GPM from the app, use your 1.6 in/hr precip rate from catch cups, and 8.1gpm. Then your calculated area is 487 sq ft. Input this into the app settings for the zone. Your sprinklers must be spraying over quite a bit, which is reflected in the higher sq ft. Area of the zone is only used for calculating usage, so will not affect run times or frequency.

I would guess that your efficiency is actually not that low. You are over-spraying, but the amount of water the lawn is receiving is probably very even.

If your sprinklers are only applying water to the lawn, then there may be another problem, like a leak.


the efficiency setting accommodates this problem which you acknowledge…

makes a really good point.


That is a great idea, calculate the ‘corrected’ area. I’m going to have to play with that later, it should work. They are spraying over a bunch, way too much, someday I’ll be reworking that zone. Thanks!


+1 to a GPM per zone. Then make sure we have an option so the gallons calculated and displayed as saved or used in the dashboard uses it. and only it.
The parade of parameters and nozzle configurations are pretty sophisticated and cool for some scenarios. I dont think you should ever take that away.
Just suggesting to add a simpler GPM option 'instead of"
That really is all the metrics I want to see and track.