A seat leak measurement system for a ball valve is described. The system includes: a ball valve with a cavity drain line, the ball valve including a cavity pressure sensor; a valve seat leak measurement apparatus including: a cable with a connector, the connector having an external grounding cable; an apparatus electronic control system in communication with the valve sensor retrieval fitting and with valves of the valve seat; an fluid inlet line with a quick pipe coupler, the fluid inlet line having an apparatus drain valve and an isolation valve; a pressure indicator transmitter connected to the fluid inlet line, the pressure indicator transmitter in electronic communication with the apparatus electronic control system; a temperature indicator transmitter connected to the fluid inlet line, the temperature indicator transmitter in electronic communication with the apparatus electronic control system; and a flow elements manifold receiving fluid from the fluid inlet line.