It is forbidden to bathe with hot water during the week of Tisha B'Ab, from the Shabbat preceding Tisha B'Ab through the day of Tisha B'Ab. This is one of several difficult Halachot that we observe during this period to commemorate the calamity of the Temple's destruction. It is permissible to bathe with cold water, and one may mix in some hot water in order to remove the chill. One may also use soap, shampoo and deodorant as usual during the week of Tisha B'Ab. A woman who needs to immerse in a Mikveh during the week of Tisha B'Ab may bathe with hot water as usual to prepare for her immersion. Bathing in preparation for the Mikveh is necessary for the purpose of a Misva, and is therefore permitted during the week of Tisha B'Ab. The accepted custom is to refrain from recreational swimming during the week of Tisha B'Ab. One who swims for health reasons is allowed to do so during this week. If one's hands became dirty during the week of Tisha B'Ab and he cannot remove the dirt without hot water, then he may use hot water for washing his hands. Otherwise, however, one should refrain from washing with hot water during this week. Summary: One may not bathe in hot water during the week of Tisha B'Ab, except in the case of a woman who must immerse in a Mikveh, or if hot water is needed to remove dirt from one's body. It is customary to also refrain from recreational swimming during this period.