Answer

No, you do not have to take tivihar pachkhan with ekashna if you want to drink water.

In Jain practice:

• Ekashna means eating only once in a day.
• Tivihar means renouncing three types of intake: food, snacks, and drinks other than water.
• With tivihar, boiled water is generally allowed during the permitted time.
• If you also renounce water, that is called chauvihar.

Explanation

If you take ekashna with tivihar pachkhan, you may drink water according to the rules of your tradition, usually boiled and cooled water, and only within the allowed time.

If you do not want to restrict water beyond normal Jain rules, you should not take chauvihar pachkhan.

Takeaway

For ekashna, water is allowed if your pachkhan is tivihar. Water is not allowed only when you take chauvihar. For exact practice, follow your guru, family tradition, or sangh maryada.