In the preparation of the sota water, it was necessary to erase into the water the writing from a parchment on which verses from the section in the Torah that discuss the sota are written. Doing so involves erasure of the name of God. Nevertheless, they would erase God’s name in order to promote marital peace.

Great is peace, as the name of God that is written in sanctity is erased in the water of the sota in the interest of peace, in order to institute peace between a man and his wife. (Sifrei Bemidbar, Naso 42)