In Jainism, ahimsa (non-violence) extends to all living beings, including very small life forms like microorganisms. Therefore, boiling water or otherwise heating substances that kill microbes is considered violence to jiva (life). A strict Jain view would say this is violence, even though the micro-organisms are tiny and not visible.

That said, Jain thought also acknowledges practical situations where hygiene and safety are important. Some traditions may recognize that in everyday life one must balance minimal harm with necessary care (e.g., using clean, boiled water to prevent illness), while still keeping the aim of reducing harm as much as possible. Digambar and Śvetāmbara viewpoints may differ in how they describe micro-life and the exact implications, but the core principle remains: violence to life is to be avoided, and any such act should be minimized and undertaken with awareness of the harm involved.

If you’d like, I can explain how different Jain texts describe jiva at micro-scales and how specific traditions pursue careful, compassionate practices around food and water.