Gen 2 Flow Sensor Operation

I am a new Rachio user. I am interrested in installing a flow sensor (CST 1"). My question is on how the Gen 2 controller uses the data. If one zone does not produce enough volume (small drip) & other zones do will the controller use the sensor data when available? (automatically move between actual versus calculated)

I can tell you unless you purchase a very expensive Badger meter, no flow sensor will be able to detect the low flows from drip zones. I know this from doing plan takeoffs from dozens of commercial projects.

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I can’t speak to the level of detection, the manufacturer would be able to help with that. If we receive flow data from zone run we use it for water usage, if we do not receive data we then we estimate the usage.

Hope this helps.


This causes me to pause and wonder if, once you get above 3/8" or 1/2" copper pipe diameters, it could be challenging to install flow sensors that have enough resolution to be meaningful for drip zones.

In my case a flow sensor for my sprinkler system would have to be appropriate for a 1" copper line (leading into the sprinkler water meter) or > 1" PVC line (coming out of the water meter).

Here’s an example of inexpensive flow measurement at near drip zone rates, that I did a few years ago. This is accurate measurement of water flow in a 5/8" copper line.

Near the bottom of the picture (before the charts), on the left side, under ‘Yesterday,’ you can see that 99.3 gals was measured during on times accumulating to 4.1 hours for yesterday’s 24 hour period.

That’s a measurement of 24 gals/hr rate, or, stated in minutes, a measurement of 0.40 gals/min.

I’m unclear what Rachio Gen 2’s plans are for its flow sensor interface - industry standard flow sensors produce a pulse count whose frequency varies as a function of flow.

Today I’m measuring flow for my Iro Gen 2 controlled sprinkler system via reading the on/off times from the master valve. This gives to me this chart: (daily usage) and this chart: (monthly usage) in hours format. To convert to gallons I too need to add a flow sensor.

My vision of what a Rachio Gen X controller would look like would include support for industry standard flow sensors, accommodation of an Ethernet connection, have a capacity greater than 16 zones (for full automatic operation), and offer a remote zone on/off accessory (that’s not an expensive phone.)

Best regards,


Yes, thanks. My main reason for the flow sensor is for pipe break detections. Rachio does not have that yet but I suspect it will be in the near future. My system 3 zones (5/8 poly) & two zones with PVC (tree bubblers), is at least 8 years old. I am now getting occasional lateral cracks in the poly. The flow sensor will be operational if that happens. I hope be able to see the GPMs go up, especially for a 3 hour drip cycle. I will have to manually check for that until Rachio has the upper limit threshold warning. Make sense?

Yes. We do hope to have this functionality and it is entirely possible with the data we receive.


It may be time to replace your drip tubing. It is very inexpensive. Check out parts at a supply house like Ewing.