This disclosure relates to dialysis venting devices and related methods. In some aspects, a dialysis system includes a fluid inlet line, a venting device in fluid communication with the fluid inlet line, and a fluid outlet line in fluid communication with the venting device. The venting device can include a housing defining a fluid chamber, a valve member disposed above the fluid chamber between a lower seat and an upper seat, and a pump that is operable to draw fluid into the fluid chamber from the fluid inlet line and to force fluid out of the fluid chamber into the fluid outlet line.