A jet pump unit (46) includes a pump housing (49), a metering valve (1) with a valve housing (2), a mixer tube area (52), an intake channel (43) and a runoff area (45). A through-hole (2) that forms a through-opening (80) is designed in said pump housing (49). The metering valve (1) is received in the through-opening (80) and a first step (200) and a second step (202) are formed in said through-opening (80), radially with respect to a longitudinal axis (40) of the jet pump unit (46), for the purpose of radially centering and guiding the metering valve (1) in said pump housing (49).