In Jainism, particularly among Shwetambar Jains, boiled water (known as ushnodaq or ukāḷūṃ pāṇī) is used to minimize harm to microorganisms, thereby adhering to the principle of ahimsa (non-violence). Traditionally, boiled water should be used within a specific time frame to avoid the re-emergence or multiplication of microorganisms.

Common Practice:

• Boiled Water Validity: Typically, boiled water is considered suitable for drinking for up to 24 hours from the time it is boiled, provided it is kept covered and in a clean container.
• During Chaturmas or Paryushan: Some stricter sects and ascetics may use boiled water only for 12 hours, or even less, depending on the local tradition and weather conditions.

Why this rule? After the specified period, it is believed that microorganisms begin to multiply again, and using such water may violate the principle of ahimsa.

Summary: You can use boiled water for up to 24 hours after boiling, as per general Jain practice. However, always refer to your tradition or guru for specific guidance.