After that he pours water into a bason, and began to wash the disciples' feet, and to wipe them with the towel wherewith he was girded. - Joh 13:5
Why did Jesus do this?
Peter says unto him, You shall never wash my feet. Jesus answered him, If I wash you not, you have no part with me. - Joh 13:8
Jesus washed the feet of the disciples to symbolically make them clean, foreshadowing how His soon-to-be shed blood would wash them from all Sin and make them a part of Him through the indwelling HolySpirit.
Yes, His act showed Humility - but so did His entire Life. He is God who humbled Himself to come to earth, to suffer and die for us.
Did He do this to teach us to wash each other's feet? I don't think so, because unlike the Communion, He did not say "as often as you do this...".
There is nothing wrong with having FootWashing services. It actually promotes Fellowship which is a good thing.
But, it is not a Sacrament and has no Spiritual efficacy for the person being washed by another person.