Bath, Bathing

Boyd’s Bible Dictionary:

Part of the Jewish ritual of purification (Lev. 14:8; 15:5,16; 17:15; 22:68And he that is to be cleansed shall wash his clothes, and shave off all his hair, and wash himself in water, that he may be clean: and after that he shall come into the camp, and shall tarry abroad out of his tent seven days. (Leviticus 14:8)
5And whosoever toucheth his bed shall wash his clothes, and bathe himself in water, and be unclean until the even. (Leviticus 15:5)
16And if any man's seed of copulation go out from him, then he shall wash all his flesh in water, and be unclean until the even. (Leviticus 15:16)
15And every soul that eateth that which died of itself, or that which was torn with beasts, whether it be one of your own country, or a stranger, he shall both wash his clothes, and bathe himself in water, and be unclean until the even: then shall he be clean. (Leviticus 17:15)
6The soul which hath touched any such shall be unclean until even, and shall not eat of the holy things, unless he wash his flesh with water. (Leviticus 22:6)
; Num. 19:77Then the priest shall wash his clothes, and he shall bathe his flesh in water, and afterward he shall come into the camp, and the priest shall be unclean until the even. (Numbers 19:7); 2 Sam. 11:2-42And it came to pass in an eveningtide, that David arose from off his bed, and walked upon the roof of the king's house: and from the roof he saw a woman washing herself; and the woman was very beautiful to look upon. 3And David sent and inquired after the woman. And one said, Is not this Bath-sheba, the daughter of Eliam, the wife of Uriah the Hittite? 4And David sent messengers, and took her; and she came in unto him, and he lay with her; for she was purified from her uncleanness: and she returned unto her house. (2 Samuel 11:2‑4); 2 Kings 5:1010And Elisha sent a messenger unto him, saying, Go and wash in Jordan seven times, and thy flesh shall come again to thee, and thou shalt be clean. (2 Kings 5:10)). Customary after mourning (Ruth 3:33Wash thyself therefore, and anoint thee, and put thy raiment upon thee, and get thee down to the floor: but make not thyself known unto the man, until he shall have done eating and drinking. (Ruth 3:3); 2 Sam. 12:2020Then David arose from the earth, and washed, and anointed himself, and changed his apparel, and came into the house of the Lord, and worshipped: then he came to his own house; and when he required, they set bread before him, and he did eat. (2 Samuel 12:20)). Public bathing pools usually sheltered by porticos (2 Kings 20:2020And the rest of the acts of Hezekiah, and all his might, and how he made a pool, and a conduit, and brought water into the city, are they not written in the book of the chronicles of the kings of Judah? (2 Kings 20:20); Neh. 3:1515But the gate of the fountain repaired Shallun the son of Col-hozeh, the ruler of part of Mizpah; he built it, and covered it, and set up the doors thereof, the locks thereof, and the bars thereof, and the wall of the pool of Siloah by the king's garden, and unto the stairs that go down from the city of David. (Nehemiah 3:15); Isa. 22:1111Ye made also a ditch between the two walls for the water of the old pool: but ye have not looked unto the maker thereof, neither had respect unto him that fashioned it long ago. (Isaiah 22:11); John 5:2; 9:72Now there is at Jerusalem by the sheep market a pool, which is called in the Hebrew tongue Bethesda, having five porches. (John 5:2)
7And said unto him, Go, wash in the pool of Siloam, (which is by interpretation, Sent.) He went his way therefore, and washed, and came seeing. (John 9:7)
).

From Manners and Customs of the Bible:

Roberts thinks there is an allusion here to one mode of bathing practiced by Orientals, which is to have water poured on the body by an attendant. The Egyptian monuments give evidence that this mode was practiced in Egypt.