After struggling with the Homekit irrigation system integration, I’m thrilled to share my success story! 
Initially, I faced issues where the ‘Active’ state wasn’t updating in Homekit, leaving my irrigation system always disabled. This was frustrating, especially during peak watering seasons.
After some research and trial-and-error, I discovered that adjusting the item definitions in my configuration made all the difference. Here’s what worked for me:
markdown
Group gIrrigationSystem “Rainbird” { homekit=“IrrigationSystem” }
String irrigationSystemProgramMode (gIrrigationSystem) { homekit=“IrrigationSystem.ProgramMode” }
Switch irrigationSystemEnabled (gIrrigationSystem) { homekit=“IrrigationSystem.Active” }
Switch irrigationSystemInUse (gIrrigationSystem) { homekit=“IrrigationSystem.InUseStatus” }
String irrigationZonetoRun (gIrrigationSystem)
Group irrigationSystemTotalRemaining (gIrrigationSystem) { homekit=“IrrigationSystem.RemainingDuration” }
This setup not only resolved the ‘Active’ state issue but also ensured all irrigation functions worked seamlessly with Homekit. I’m now able to control my irrigation system remotely, schedule watering programs, and monitor the system status effortlessly.
If you’re encountering similar issues, I highly recommend checking your item definitions and ensuring they align with the latest Homekit specifications. A small tweak can lead to a big difference in functionality! 
Happy gardening and happy automating! 