A gas line leakage monitor for beverage dispensing system is configured to prevent unintended environmental discharge of a beverage dispensing gas such as CO2. The monitor includes a gas inlet coupled to the source of gas and a gas outlet coupled to the dispensing portions of the system. The monitor includes a flow sensor detecting when gas is flowing through the monitor. The monitor includes a timer coupled to the flow sensor and tracking the amount of time that the flow sensor detects at least each episode of un-interrupted flow of gas through the monitor. The monitor includes a shut-off valve coupled to the timer for stopping the flow of gas through the monitor and to the system's dispensing portions when the timer indicates an episode of un-interrupted gas flow through the monitor meets a pre-set threshold. The monitor includes a manual reset for opening the shut-off valve.