A valve seat leak measurement system, the system comprising: a ball valve with a cavity drain line controlled by a cavity drain valve and a valve sensor retrieval fitting, the ball valve comprising a cavity pressure sensor; a valve seat leak measurement apparatus that is coupleable to and decoupleable from the valve sensor retrieval fitting, the valve seat leak measurement apparatus comprising: a cable with a connector compatible with the valve sensor retrieval fitting, the connector having an external grounding cable to ground the apparatus to a valve body ground terminal; an apparatus electronic control system in communication with the valve sensor retrieval fitting and with valves of the valve seat leak measurement apparatus; a 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, the flow elements manifold including a plurality of flow runs (420, 421, 422), each flow run (420, 421, 422) operable to measure a different range of flow rates, each flow run including an orifice (372, 377, 382) and a differential pressure transmitter (369, 373, 378) in electronic communication with the apparatus electronic control system. a ball valve with a cavity drain line controlled by a cavity drain valve and a valve sensor retrieval fitting, the ball valve comprising a cavity pressure sensor; a valve seat leak measurement apparatus that is coupleable to and decoupleable from the valve sensor retrieval fitting, the valve seat leak measurement apparatus comprising: a cable with a connector compatible with the valve sensor retrieval fitting, the connector having an external grounding cable to ground the apparatus to a valve body ground terminal; an apparatus electronic control system in communication with the valve sensor retrieval fitting and with valves of the valve seat leak measurement apparatus; a 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, the flow elements manifold including a plurality of flow runs (420, 421, 422), each flow run (420, 421, 422) operable to measure a different range of flow rates, each flow run including an orifice (372, 377, 382) and a differential pressure transmitter (369, 373, 378) in electronic communication with the apparatus electronic control system. a cable with a connector compatible with the valve sensor retrieval fitting, the connector having an external grounding cable to ground the apparatus to a valve body ground terminal; an apparatus electronic control system in communication with the valve sensor retrieval fitting and with valves of the valve seat leak measurement apparatus; a 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, the flow elements manifold including a plurality of flow runs (420, 421, 422), each flow run (420, 421, 422) operable to measure a different range of flow rates, each flow run including an orifice (372, 377, 382) and a differential pressure transmitter (369, 373, 378) in electronic communication with the apparatus electronic control system.