It's good to be lucky! The city sends me reminders about a month in advance of the due date every year for my car wash and laundromat. Inspections run about $150 each every time. If there is a problem, the guy that inspects them is also certified to repair them through his sideline business. According to our city's code, if I make even a small repair (like changing out a 1/4" ball valve that was dripping), I'm supposed to let them know so they can come out and inspect it again for ~$150. The only way our hydrominder would meet air gap requirements would be if it withstood an airplane crash that also broke the city water line. They went so far as to tell me that if I own a garden hose that can be laid on the ground, there is a possibility for cross contamination. Basically, every business in our town is required to have back flow prevention. Residential is also required to have backflow prevention if they have any kind of sprinkler system. However, the majority of people and businesses in our town are also lucky - as they have never been inspected and if they have, it's been years.