Here Jesus speaks about "bathed" and "wash" and "clean" to mean making someone spiritually clean or pure. Since Jesus said in 13:7 that the disciples would not fully understand what was happening, translations should keep the "washing" imagery and not try to explain it in the text.
# He who is bathed has no need, except to wash his feet, but he is completely clean
The word "but" shows the contrast between a person needing to be cleaned and a person already being being clean. In some languages "but" would not be used. Alternate translation: "He who is bathed has no need, except to wash his feet, because he is completely clean" or "He who is bathed has no need, except to wash his feet; he is completely clean" (See: [[rc://en/ta/man/translate/writing-connectingwords]])
# has no need
It is implied that this need concerns washing the whole body. Alternate translation: "has no need to be fully bathed" or "does not need me to wash his whole body" (See: [[rc://en/ta/man/translate/figs-explicit]])