In Jain Dharma we avoid drinking water after sunset mainly for Ahimsa and discipline.

• Ahimsa (non‑violence): At night and in still water, innumerable tiny beings (sūkshma jīvas) arise and move more. Drinking then risks harming them. Taking water only in daylight, after proper inspection and filtration, reduces this himsa.
• Samyama (self‑restraint): Fixing a limit—no intake after sunset—cultivates carefulness, contentment, and regularity in conduct.
• Shuddhi (purity/care): In light, one can see and strain water properly; in darkness mistakes happen more easily.

Tradition-specific notes

• For monks and nuns (both Digambar and Shwetambar): Strict rule—no food or water after sunset; water is taken only in daylight, properly strained/boiled as prescribed in their conduct texts.
• For laypeople (shravaks/shravikas): Observed as a vrata. Many keep

- Tivihar: no food at night, but water allowed if needed. - Chauvihar: neither food nor water after sunset. These are especially practiced during Paryushan, poshad (upvas-like) days, and on pratikraman days.

Practical guidance

• Use only strained/previously boiled water during the day.
• If there is genuine health need (illness, medication, pregnancy, extreme dehydration), Jain conduct allows exceptions for householders—protecting life is also dharma. One should take care respectfully and, when possible, reaffirm the vow the next day with pratikraman.

This practice comes from the conduct teachings (Achara/Ācāra granthas) that emphasize daylight eating/drinking, careful inspection, and minimization of harm—preserving the spiritual intent of Ahimsa and vigilance.