Balinese Nunas Tirtha Wangsupada, source: Tropenmuseum Collection by Wereldmuseum Amsterdam
Just like in many other religions, the holy water is believed to be the manifestation of God's power that has the ability to cleanse and purify ones from spiritual impurities or the attack of negative or demonic forces. There are three (2) types of holy water in Bali: Tirtha Pembersih or Cleansing Holy Water and Tirtha Wangsuhpada or Blessing Holy Water. Tirtha Pembersih is used to purify the upakara (the offerings and ceremony tools) and one's body before sembahyang (prayer) or ceremony, meanwhile Tirtha Wangsuhpada is used after to close the ceremony symbolizing the blessings from Sang Hyang Widhi Wasa to the people who attend the ceremony.
When nunas tirtha wangsupada (asking for the tirtha wangsupada), one will be sprinkled three (3) times by the priest to symbolize the purification of one's thoughts, one must drink the tirtha three (3) times to purify the words that will come through the mouth, and one must rinse the upper chakras area (on top of the head, face, ears, and neck) to purify the actions that one will be done.
There are two (2) ways to get the holy water: tirtha made by Sulingih or Sang Dwijati such as Pedanda, Empu, Rsi, or Bhagawan for big ceremonies; and tirtha asked from pemangku or pinandita for small ceremonies, this type of tirtha can also be obtained from sacred pertirtaan such as holy springs or other places that are considered sacred.