Short answer: There is no fixed “number of times.”

• In Tivihār, only boiled and filtered water (ushṇodaka) may be taken during daylight (after sunrise and before sunset). After sunset, water is avoided.
• Take water as sparingly as possible, in mindful sittings, preferably after reciting Navkār Mantra.
• Traditions differ: Among many Śvetāmbara lay followers, water may be taken multiple times in the day. In some Digambara practices of upavāsa, water is restricted (often to once before sunset). Follow the guidance of your local guru/sangh.

For a simple explanation of Tivihār/Chauvihār from the same Jain perspective, see this reference: