WETS Irrigation Technician Practice Exam

One-way flow control is what a check valve provides. It acts like a one-way door in the irrigation line, letting water move forward but blocking any water trying to flow backward. This prevents water in the laterals from draining back toward the pump or main supply when a zone is turned off or pressure changes, so downstream zones stay pressurized and the risk of backflow contamination is reduced. It isn’t used to regulate how much water passes through, nor to boost pressure, nor to collect sediments—that’s handled by regulators, pumps, or filters respectively.