Jains drink water as a necessity for life and health, but they try to do it with maximum care and minimum harm to living beings.

In Jain Dharma, water is considered to contain life forms, so Jains follow these principles:

• Drink only when needed, not carelessly
• Filter water when possible
• Avoid wasting water
• Some Jains prefer boiled or stored water, depending on tradition
• During certain vows, fasting, or religious observances, some Jains may avoid water for a period

So, Jains drink water because it is essential, but they do so with Ahimsa and awareness of non-violence.

If you want, I can also explain why Jains filter water or what kinds of water practices are followed in Jainism.