How do I do a Catch Can/Cup Test on this yard!?

I really want to adjust my precipitation rate and efficiency for each zone but can’t figure out how I would do a catch can/cup test on my back lawn.

There are 4 zones and sprinkler heads in those zones are spread all over the yard, not just in one are of the yard, and are a combination of rotary and fixed heads. You can also see there is a lot of overlap between various zones.


First off, I would HIGHLY suggest switching one set of heads, so that everything matches. Fixed spray heads will typically put out 2-3 times as much water as a rotary nozzle (are we talking rotors, or rotary nozzles?). It is definitely going to be a tricky one as the layout design is pretty poor. Some areas have just 1 or 2 spray patterns hitting them, while the bottom left corner, I think I count 5-6 heads that are hitting it.

I totally agree it’s not a good layout but kind of stuck with it. If I can figure out how to do a catch cup test with all the overlapping zones, I can probably reduce the flow rate on the heads that overlap a lot with other heads and try to get things balance out.

Just not sure how to do the test with all the overlapping zones. Any suggestions?

Place a number of cups around the yard (I did kind of a grid pattern), and run each zone for the same amount of time. The time you run kind of depends on what the PR of the zone is (how long does the zone usually run?). If high PR heads, then I wouldn’t run for more than 10 minutes. Low PR heads like my Hunter MP Rotators, I ran my test for 30 minutes). From there, just multiply to figure out your inches per hour. Make sure to include the areas like the bottom right corner that has a single fixed spray nozzle!

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After doing this, how do I get the precipitation rates and effeciencies for each zone so that I can input it into the advanced settings of each zone? If I run all the zones at once, won’t it just give me an overall precipitation rate across all zones?

Would I just estimate which cups belong to which zone?

Are any of these zones also spraying in the front yard? Hopefully not…

What you can do is set all the zone parameters for these zones in the backyard to exactly the same values. That way they will always water on the exact same days. Obviously there is some inefficiencies here as if one of the zones is in full sun and another shady, one zone will be watering too much. But I think this is a reasonable compromise for your situation.

I would place a bunch of catch cups or tuna cans, etc. all over the backyard and run it zone by zone and collect the numbers. This way you know how much water from each zone is going where (in case you want to try modifying nozzles or changing sprinklers for better coverage later - you’ll need this info). Then you can add up all those numbers together for your total precip rates in that catch cup for all the zones. Do the catch cup efficiency math on these totals and put them into Rachio (for every zone). Now all those zones will have the exact same settings. Not idea, but with such spread out sprinklers overlapping multiple zones, it’s a decent compromise.