@cr8it - if the irrigation system was put in with each zone supporting plants with similar needs the Rachio should do just fine. The largest Rachio today is 16 zones. There are people that have multiple Rachios to support more that 16 zones and one needs to manually configure the units to where they won’t both be irrigating at the same time if the water pressure is an issue - probably not in Phoenix if you’re running a drip system. There are lots of member of the community that are from Phoenix or Arizona. I think you can have as many schedules as you have zones, so A, B, C, D, E, F, G, H, I, J, K, L, M, N, O and P.