Getting notified when things fail
OK, so you do have a security system with cellular notifications...  You are probably aware you can add freeze sensors and flood sensors to communicate alerts through that system.  That is at least some peace of mind if you're out of town and a pipe breaks or the furnace fails.  But I have yet to hear of outdoor sprinkler system alerts.  You might check with the sprinkler system company to ask if anything like that is being developed (if you haven't already asked them).  Another thing to consider is surveillance cameras.  Being able to take a peek using your smart phone now and then is some peace of mind until sprinkler systems can report malfunctions.