If your home has a sprinkler system for the lawn, your sprinkler system must have a backflow preventor to prevent contaminated water mixing with your drinking water. Each year the backflow preventer must be certified by a trained plumber or backflow technician. Using your sprinkler system with a damaged backflow preventor could allow chemicals, pesticides or herbicides to enter into your home’s drinking water. This can be quite dangerous and cause health risks to you and your children.