In Jainism, Ekashana (or Ekasana) is a practice where one takes only a single meal during the day. The rules regarding water intake can vary depending on one’s tradition (sect), personal vow, and the level of strictness one is observing.

Generally:

• For Ekashana, both food and water are typically consumed together during the single meal period, and not before or after.
• Strict practitioners avoid drinking water before and after the meal; water is only taken with the meal.
• After the meal is concluded and the mouth is rinsed, one refrains from consuming both food and water until the next day.

How to know your timing:

• You can have water only during your ekashana meal—not before and not after.
• The meal should be taken during daylight hours, generally before sunset (often before 4 PM, depending on tradition and season).

Advice: If you follow a specific Jain tradition (like Shwetambar or Digambar), or are under the guidance of a guru, follow the rules as instructed by them, as there may be slight variations.

Summary: On the day you are observing ekashana, you may have water only during your single meal, and not at any other time.