Your garden hose is one of the most common causes of backflow. For example, let’s say you’re watering your garden with a pesticide applicator attached to the end of the hose. Your kids want a snack, while you’re inside fixing the snacks there’s a drop in water pressure in the supply system that causes a vacuum… this will pull the pesticide-laced water into your home. The worst part is you most likely won’t have a way of knowing that backflow has occurred.

This poses a big problem because usually water is purified through either natural processes (filtering through bedrock or soil) or through artificial processes (reverse osmosis). Neither of these processes is possible once water is already confined within the main lines of your home. It’s much easier to prevent this problem from ever happening than it is to remedy after the fact.

Water pressure drops are not uncommon, it may happen while a crew repairs a broken water main or firefighters put out a nearby fire.