How to bill for utilities on the side when using AirBnB?

[Lance Tokuda]

Hello, my neighbor wants to rent my 2nd home in California while she is remodeling.  I was planning to use AirBnB to take care of liability and rent collection.  On the side, she has agreed to pay for utilities. 

1.  Do you have suggestions on how to make the utility bill official?  If you have pointers to any public domain documents I could copy or other advice, that would be greatly appreciated!

2.  She says that I should pay for water used to maintain the lawn (single-family home).  Who normally pays for the water used in lawn maintenance?  I agreed to pay for the lawn care.

Thanks in advance for any tips!