Do you charge for a work order fee?

[Chance Cooper]

I have a current tenant that has been crying about his water bill for 3 months now…I sent 2 people over there and they found nothing that would cause him to have a high water bill. The city even came out, and nothing…

Finally he calls again on the 1st and asks for a discount on the rent due to the high water bills as of late…Fed up, I decided to drive down there (120 miles one way) to crawl under the house and find out what, if anything was wrong…I get there, go under the house and nothing. I asked him to run the washing machine, nothing…As I am under the house waiting on the washer to do its thing I was talking to him through the ventilation vent and he says "I detail a few cars on the side each month maybe 5-7, but that can't be the reason my water bill is so high…" 

Right then I become extremely pissed because thats got to be the reason…Your running a car detailing business. I don't have a problem with that, but I do have  problem with the constant phone calls about the water bill or whatever else under the sun he thinks he can use to get me to knock some off the rent with. Do any of you guys charge a work order fee or anything like that? I am thinking that if I charge a minimum fee it will make the tenant think twice before they call me. If they are willing to pay the work order fee that tells me that they really think something is wrong.

Any thoughts on this?