Rachio suitability for aerobic ferment septic system

Hey folks, I have an aerobic fermentation septic system that is currently set up with dripper lines (that have become useless due to being trodden on when installed above ground where stock graze). I want to remake the whole system to water an orchard area (also drip/trickle) as well as having the option to send the treated water to a paddock during the winter to avoid over watering for the months where it is near constantly wet.

My idea is to set up several zones for different groups of fruit trees, and the winter paddock that all run on solenoids, only thing is that because the septic system needs to run on a float (when it needs to empty, it needs to empty), the solenoids will only open or close off the zones versus regulating the flow. Not sure if this makes sense, but put another way when a valve opens, there won’t necessarily be water flowing since the pressure is only there when the float actuated septic pump comes on (ie someone has a shower or does the laundry)…

Assuming that is clear, a few questions for you irrigation gurus, particularly with respect to the Rachios since I haven’t yet bought the controller… I have read that some valves need pressure to turn on/off, is this the case and if so what type of valves would be appropriate given there won’t be pressure behind the valves most of the time when switching? I envisage just leaving a zone open for a couple of days to allow a few empty cycles to water the area, then close that zone down and then open another for a couple of days. Again I haven’t yet bought the controller but do people see any issues having long (2 days) on-times? I also have a Davis Instruments weather station that can report data to externally hosted weather servers, I’m aware some of the new wireless irrigation controllers should be able to make use of that info but wondering if these ‘smart’ options will be smart enough for my whacky on/off schedules - any comments or experiences there? Looking at the Rachio 2 controller as am in New Zealand and I believe the Rachio 3 is out due to broadcasting frequency conflicts. Have also read that the Rachio 3 can be modded to prevent that though so if there are opinions as to why it might be better for what I’m trying to achieve then interested in that possibility also…

Thanks in advance

Bump, I realise I wrote a lot, but answers to any one of the questions below would be much appreciated!

@Greenthumb - here’s my $0.02 (US).

  1. In many configurations, there is a potential failure mode where the septic pump comes on and there is not a valve open to release the flow.

  2. I don’t think the A/C based solenoids would like/last long with a multi-day on cycle. I’d investigate a latching type solenoid (DC based I believe) or a gate/ball valve that is actuated on or off. Another option would be to put the power to the solenoids behind a relay that would turn on when the septic pump turns on. This way the solenoid wouldn’t be on all the time.

  3. I don’t think the Rachio is fit for function on the proposed layout. All the smarts are wasted. A simpler setup with relays to open or close might be better.

If one wanted to use all the Rachio smarts to irrigate, then I’d pump the outflow into a holding tank (large enough to handle an irrigation cycle and septic generation between cycles, with an overflow pipe and a low water level switch connected to the Rachio rain sensor - to protect the pump from running dry) and have a pump that the Rachio would start (pump start relay) to irrigate. Schedules could be set up in Rachio based on dates to use different zones.

In addition to the Gen 3 900 MHz antenna removal one will need a 24 VAC transformer that works with NZ power as the Rachio comes with a US power based transformer for either Gen 2 or Gen 3.


Great, thanks for that @DLane definitely given me a bit more to think about.

I had also wondered about how to setup to make sure that water can still flow somewhere if something fails - was thinking maybe a 3-way solenoid there that splits flow between the orchard and soaker paddock. That way if it becomes unresponsive then water will go to wherever it was last being directed.

I like your idea of running the solenoids off a relay that is triggered by the septic pump, would definitely be a smart way to do it… So have the controller still programmed to do day on day off type watering but route that signal through the relay that is triggered by the float switch maybe?

I realise this is not using much of the smarts, but really want to incorporate some of that into the system. Being able to send the water to the soaker field if it has rained will be quite important I think as the aerobic system takes care of most of the nasties, but the treated water can have a fair amount of nutrient/salt in it. In this way its as much about over-nutrification as it is about overwatering, so be good to give rain the chance to dilute/flush the soil base.

What about having the rachio run a single smart zone controlling the 3-way valve (ie weather feedback, orchard or soaker paddock), and then have the other zones doing regular cycle watering for the different orchard tree groups on top. The ‘dumb’ circuits would also only energize when the septic pump runs via relay. Could the rachio pull this off ya think? Still have problem of long on times for the three way valve I suppose…

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@Greenthumb - not sure how the Rachio smarts would send the treated water to the soaker field if it has rained. I might try something using IFTTT to trigger a relay based on weather/rain or a rain sensor. I’m also not sure how Rachio would handle the long (multi-day) zone times.