Chauvihar means: after local sunset, no food and no water until the next sunrise. This is observed to avoid harm to night‑born beings and to keep saiyam.

Water timing

• Stop drinking water at the exact local sunset time for your city.
• Resume water after sunrise (daylight), using only properly boiled and filtered water.

Notes by tradition

• Digambar: Only boiled (ukālelū) and filtered water during daytime; strictly no water after sunset. Same rule for laypeople and stricter for sādhus.
• Shvetambar (Deravasi/Sthanakvasi/Terapanthi): Same practical rule—no water after sunset; daytime water should be filtered, and many observe only boiled water.

Practical tips

• Check the day’s sunset for your location and finish your last sip a few minutes before that time to be safe.
• Keep separate boiled-and-cooled water for daytime use; do not use unboiled water.
• Health exceptions: If genuinely required (e.g., medicine), take pachchakkhān (a vow/permission) as per your tradition’s guidance and your doctor’s advice.

Essence

• Chauvihar water timing = from sunset until sunrise: zero water.