Handwashing in school

My 9 year old son has a severe peanut/tree nut allergy. He is also highly allergic to eggs, dairy, wheat, oats, barley, rye, sesame, and garlic. He has successfully made it through preschool and grades k-3rd grade safely due to my husband and I educating our schools. They have done a great job keeping him safe. This year will be different because he will be moving classrooms during the day for different subjects. Previously, we have been able to have each student wash their hands before school and after lunch before entering their nut free classroom. This will be much more difficult to accomplish with 60 kids and 2 classrooms. I know many of you have your peanut allergic kids in school. My question is, does your school have students handwash also? What is the norm here? I don't know if we have been doing more than other schools or if this is happening in your schools too? Any advice or direction would be helpful. For the first time I am feeling unsettled about sending him and am considering homeschooling. I know it gets more complicated as they get older, and change classrooms every period. I just wasn't prepared for it to be in 4th grade.