I run my business out of my home. Almost 2 years ago a new neighbor called code enforcement to complain that I was was running a business out of my home.
Luckily one of my dog walking clients is an attorney and he was able to advise me. Long story short: here in this town one is allowed to operate certain types of non retail businesses in an area that is zoned residential. There can be no exterior evidence of the business such as signage. Also in my town there is a very specific "dog barking" law. Dogs cannot bark continuously for more than 20 minutes. I have never received a barking violation as I do not allow my dogs to bark for long. Of course dog barking is unavoidable if the ups driver comes to the door for example but that is short term barking. However anyone who owns dogs in a residential neighborhood may have barking dogs. So my neighbor's complaint about barking dogs was unfounded. He lives across the street and down the road by the way. I can't wait for someone to move in next door to him with 5 Yorkies, karma is a bitch.
I have linked one of the articles from the local paper about my saga below. The bottom line is this: if you are running a pet sitting business out of your home, learn your local codes, keep noise to a minimum and don't be intimidated by your neighbors, hire an attorney. I have a great one.