Most medieval baths were actually showers of sorts
Fuel to heat water for baths was expensive, in more ways than one. In cities and larger towns it had to be purchased from woodcutters. In smaller towns and isolated communities it had to be cut, split, gathered, and stacked. One method took cash or barter, the other an investment in time. To apply such an investment to the heating of water for the purpose of taking a bath was deemed a luxury. Using enough hot water, heated with expensive firewood, to allow full immersion in a tub was an extravagance bordering on waste. Instead, most baths involved standing in a receptacle to catch water poured over one’s head from buckets or pitchers. Saving the water allowed it to be reused. Waste not, want not. In families with a single tub, the male head of the household bathed first, followed by the other males of the household.
The matron of the house followed the procession of males, after which daughters were bathed, based on their seniority. Thus, the last to be bathed was laved with water which had previously cleansed the bodies of parents and siblings. Only toddlers and infants were immersed, their older siblings were simply rinsed with increasingly dirty water. The youngest being bathed last is the source of the remonstrance not to throw the baby out with the bathwater. Nobles and the wealthy had their own bathing rituals and procedures, which reflected their higher status. There is a reason the so-called common people have long been known, disparagingly, as the “great unwashed”. Bathing usually took place in early summer, and again in the late fall following the harvest, when all enjoyed their baths, whether they needed them or not. Soap, being expensive and often reserved for laundry, was optional.