The present invention relates to a transport container system 10 for an interchangeable water analysis sensor cartridge 12. The transport container system 10 consists of an interchangeable water analysis sensor cartridge 12 having at least two different sensor membranes 22, 24 and of a transport container cup 14 having for each sensor membrane 22, 24 a separate moist chamber 47, 48 with in each case one chamber opening 46, with the moist chambers 47, 48 having a humectant 42 that is specific for the sensor membranes 22, 24. The humectant 42 is introduced into the moist chamber 47, 48 by way of the chamber opening 34. Furthermore, the contact between the sensor membranes 22, 24 and the humectant 42 arranged therein is made possible by the chamber opening 46.