In Jainism, ekashana refers to the practice of taking only one meal a day, usually during daylight hours. The rules around drinking water during ekashana are observed with great care, especially by monks, nuns, and serious lay practitioners.

According to Jain tradition:

• Water should only be consumed during the meal (ashana) itself, not before or after.
• Once the meal is completed and the practitioner has finished eating, they should not drink water until the next meal on the following day.
• This is to maintain the vow of limiting intake to that single occasion and to minimize harm to microorganisms in water, as recommended in Jain scriptures.

For lay followers (shravakas):

• Some may take a slightly relaxed view, allowing boiled or filtered water to be taken at intervals during daylight, but strict ekashana observance means water is taken only during the meal.

Summary: In ekashana, water should be drunk only during the single meal and not before or after, until the next ekashana.

This practice exemplifies discipline and carefulness (samiti) in observance of Jain vows.