Baths consisted of a big tub filled with hot water.
The man of the house had the privilege of the nice clean water,
Then all the other sons and men, then the women and finally the children.
Last of all the babies.
By then the water was so dirty you could actually lose someone in it.
Hence the saying, "Don't throw the baby out with the bath water!"
I once worked with two of the tightest men ever to walk the Earth, both Senior Managers. They shared teabags, one had first dip one week then vice versa the next week.
in my mums family the baby bathed first in a large bowl, the water was then poured into a bigger bath with a jug of hot and the kids went in one at a time with a jug of hot going in between to keep it warm, so as more kids were bathed the deeper the water got, till 'the old man' went in last, this was because the water had to be drawn up from the well and carted in buckets, the hot coming from the copper that the washing was done in, no water was wasted.