Hey neighbor.

I noticed your sprinkler running after watching you leave for work. I assumed you may have forgotten to turn it off. I hope that is okay that I took the liberty of turning it off myself. BTW, your yard is looking GREAT..!
You were correct in your assumption and I appreciate your taking action. Despite my apparent carelessness, I do in fact strive to lead a life as green as possible.

Thank you.
You're welcome.