Back-to-school time is lay-down-the law time.

As all the kids go back to school, Moms and Dads are busy laying down the ground rules to help make it a successful year.

Little ones get instructions on crossing the street, holding hands, and eating their lunch.

Middle-school kids get cautionary tales about bullying behavior, harder homework, and budgeting their time.

High school students get lectures on safe driving, curfews, and the looming threat/promise of college — which means “buck down and buckle-down, now.”

But for the first time in decades there is another back-to-school-rule that is being stressed with great seriousness and grave concern — “Wash your hands. With soap. Often!”

Along with the new backpacks and lunchboxes, and lockers, we are being told to expect a new outbreak o…