Catch Cups

Orbit sells a set of catch cups:

…and has a easy-looking online calculator, where you pop in the data, and it tells you how long they recommend you run your sprinklers. It also does the math to tell you your uniformity.

Would this be a good idea for calibrating my Iro? I know I could do it cheaper with some cups and a ruler, but to be honest, I’d rather spend a few dollars and make the process easier and more accurate.
When I get the results, would I just adjust the running time for the zone in the Rachio app? (That sounds like the simple way to handle it.) Or would it be better to somehow use the data to figure out the average GPH of my sprinkler heads for that zone and set a custom head to that GPH? I don’t want to do something to mess up the plus/minus calculated adjustments that the Rachio app will apply to my system throughout the year.


Excessively expensive, made in China, but possibly the only game in town?

This is what I got… 10 pack and much cheaper.


Also, for those of you with drip irrigation, it’s really hard to read the printing on the heads to know what your GPH (gallons pre hour) rate is. Here’s a quick way to find out.

Measure how many seconds it takes to fill a tablespoon:
14 seconds equals 1 gallon per hour (gph)
7 seconds equals 2 gph
4 seconds equals 4 gph


If that’s legit, I’ll definitely be trying that method, thanks

No reviews… I wonder if those markings are correct

@Ed3120, I would think you would want to plug that number into custom nozzles and adjust the efficiency from what you found as well. Trying to just adjust the actual running time would be messy as other factors like root depth and available water and MAD and maybe more for all I know go into the equation of how long your run time really should be.

The yellow cups I linked to I purchased a few years back (may have been from another vendor on Amazon) and they are accurately marked.


Thanks. With shipping those are $18, as opposed to $25, so it’s a little cheaper. I feel like something with a wider mouth would possibly be a little more accurate.

This is the way to go. I know the Orbit catch cups seem excessively expensive, but they are easy to work with and the data is invaluable in making a dent in the thousands of dollars in water many of us spend a year.

Do two things with the data: (1) create custom nozzles, and (2) use the uniformity data for each zone.

I do think the Orbit cups look a bit nicer than mine in hindsight. Question: is the uniformity percentage that Orbit calculates the same formula that is appropriate for entering in Rachio’s “efficiency” slider? If so that makes it brain dead easy.

Great teamwork by the community today!

We designed the app to be as accurate and simple as possible. However, incorporating catch cups can increase your water efficiency.

And, at the end of the day, we are all here to conserve water.

Yes. That’s how to use it.

This might seem a little over the top, but for my own use I created a spreadsheet with two tables. The first has each zone on the vertical axis and each head type in my yard on the horizontal axis with the number of heads in each zone. Since I know the supposed GPM for each head, I can then calculate the “theoretical” amount of water being put down in each zone. Measure the square footage, and you can then calculate the amount of water supposedly being put down each hour.

On the second table, I put each zone on the vertical axis and catch cups 1-12 on the horizontal axis. Recorded the catch cup data (for me, ml/15 min), then calculated the average and efficiency over on the right. Can compare this to the first table to see how the numbers compare, and use this data to create custom nozzles (I would say the fewer the better).

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I bit the bullet yesterday and bought these. I’ve tried for weeks to get motivated to use these little bowls we had around the house, but I just couldn’t get myself to try and do them correctly and then have to find a way to accurately measure them.

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In the end, the online Orbit calculator tells me how many minutes I should run the zone. I assume that it’s recommended that instead of adjusting my runtime in minutes, I should use that number to figure out my average inches per hour, create a custom nozzle, and recreate the zone in the Rachio app.

How do I calculate the inches per hour that I should use for the nozzle when I have the runtime number in minutes?

I found this website: referenced in another post to be more useful than the Orbit site for figuring out average rates and efficiency.

And if you want to convert GPM to in/hr, use this formula: (96.25 x total GPM) \ Total zone area = precip rate.

I just tested my drips out, all of them are 7 seconds to fit a tablespoon. Thanks again for this info. Now I just gotta figure out what that means for inches per hour

Have I got a deal for you. Here’s a web site that does that calculation for you. Water Application Rate Calculator. Take your drip rate in GPH and the area in sq. ft. or sq. inches that the drip covers. Plug that into the calculator and you will get in/hr.


I tried the online Orbit calculator and it’s confusing. I’m not confident with using the runtime that it is giving because it asks for your soil type, and depending on what you answer, the numbers change. I don’t want soil type factored into my number because I wanted the Rachio software to handle that calculation and I don’t want my soil type to be factored in twice.

I ran my sprinklers for 10 minutes in a single zone. I have 8 fixed head sprayers in this zone. The catch cups catch 16 square inches each, and I put down 11 catch cups. The cup with the lowest amount was 20 mL and the cup with the highest amount was 95mL. The average was 53mL.

So I know that on average, in 16 squares inches of area, 53mL falls in 10 minutes, and I’m using 8 nozzles to do that. I’m not sure what to do with those numbers to get an inches per hour for my nozzle type.

I found the below PDF that made the most sense to me. Using the instructions I was able to calculate the in/hr and efficiency for my system: