In today’s world, where many people shower at least once daily, not showering can be a cause of discomfort. Where there are two days of Yom Tov – such as a Rosh Hashana in all places or other Chagim in chu’l, this concern is deepened. In some cases there can be three days of Chag and Shabbat. For many people, the idea of not showering for three days is distressing!
Nevertheless, on this question it is common for people to get different answers from different poskim. The range of issues on which rabbis disagree is particularly marked. For instance:
some rabbis allow showering the whole body, others up to half the body, others the whole body limb by limb, others just the face, feet and hands, and yet others do no allow stepping into a shower at all.
some allow showering in hot water, others in lukewarm water, others in cold water and others not at all.
some allow showering in water heated on Yom Tov, some only in water that was heated on Erev Yom Tov and other not at all.
some differentiate between a bath an a shower, others between a private bathroom and a more public one (eg in a dorm) and others make no such distinctions.
some differentiate between a one day, two day and ‘three day’ Yom Tov; others do not.
some differentiate between a regular boiler system and a solar powered dud shemesh system.
As we will see, the halachic sources on this issue are difficult to unpack – there are three separate issues that we will need to examine separately – but this will be’H enable us to understand where each opinion is coming from.