Holy water accompanies every act of Hindu-Balinese worship, from individual devotion at household shrine to islandwide ceremonies. The Balinese call holy water toya, from the Medium Balinese word for “water,” and often the High Balinese tirtha will be used.
Holy water is an agent of the power of a god, a container of mysterious force. It can cleanse spiritual impurities, fend off evil forces, and render the recipient immune to the attacks of negative, or demonic influences. In Bali, holy water is not a symbol, or something abstract – it is a sekala container of a niskala power, and, as such, is sacred and holy in and of itself. The water strengthens and purifies everything it touches,. Although there are many kinds and potencies of holy water, no matter where or by whom it is made and no matter whether its quantity is greta or small, holy water is always a sacred and powerful agent.
The uses and potency of holy water vary according to how it is made, its source, and who makes it. The more powerful the mantras used to make it, the more mystic energy it contains. The more sacred the place from which it is obtained, the greater the sanctity of the holy water. The more exalted the status of the person who makes it, the greater its magical power.
Holy water requires special handling, it must be treated with respect and deference. The most important rule to follow is that the holly water must be stored in a clean container and must be handled with great respect
Holy water is so essential to Balinese life that it is impossible to list all its uses. Those who are sick are made well by balians or pemangkus who clean the spirits of their patients with holy water. A Balinese undergoes such a cleansing before and after any major trip. Everyone of the rites of passage involves the use of holy water. Shrines are sprinkled with it every day. Those who go into trance are brought back from this state with holy water.
Source : HOLY WATER, Substance and Symbol, on Bali Sekala & Niskala, by Fred B. Eiseman, Jr.