Deductions & credits

Thank you. I am starting to figure this out. When a client or other work related person comes to my office for an appointment, I can deduct refreshments offered to this person. Otherwise, I would not.
However, if there is no water in the office, and it looks like a water utility bill is a legitimate deductible expense, then drinking water for the office should also be deductible, even if I am the only one there? Comments appreciated.