When you say the word "backflow" most people thing about a drain backing up. In the plumbing world, however, “backflow” refers to the water distribution side of things.
Why would a customer prefer a flat rate price as opposed to hourly? First of all, almost everything you buy on a daily basis is flat rated these days. When you go out to dinner everything on the menu is a set price. When you buy an item of clothing it is at a flat price on the tag.
