We have an electrical business. We have been told it is perfectly legal to add a “3.5% processing fee” stated on the bill if the customer would like to pay by credit card. If they mail a check they can deduct it. I’m in Connecticut. We don’t do much in credit card and get hit with 3.8%. So recouping some is better than none. We thought about just upping our rates but that really isn’t fair to those that Mail a check, which is still about 75% of our business.