Question of the Day

I am watching my neighbor break down his RV. He dons heavy duty black gloves (reminds me of something you would use when handling nuclear waste) and works on the septic hose. He then removes his gloves and unhooks the drinking water hose. For those that don't know it is a white hose. He then proceeds to don the heavy duty gloves and uses the drinking water hose to flush out his septic hose. I am talking stick the hose all the way down and flush. Why is he so afraid of touching something nasty and not afraid of drinking something nasty. Will someone explain that to me?